Rules for the classification of ships, Part 3, 2013 - crs.hr for the... · RULES FOR THE CLASSIFICATION OF SHIPS Part 3 ... draught to be assigned to the ship, see the Rules, Part

RULESFOR THE CLASSIFICATION OF

SHIPS

Part 3 - HULL EQUIPMENT

2013

CROATIAN REGISTER OF SHIPPING

Hrvatska (Croatia) • 21000 Split • Marasovićeva 67 • P.O.B. 187Tel.: (...) 385 (0)21 40 81 11Fax.: (...) 385 (0)21 35 81 59

E-mail: [email protected] site: www.crs.hr

By decision of the General Committee of Croatian Register of Shipping,

RULES FOR THE CLASSIFICATION OF SHIPSPART 3 – HULL EQUIPMENT

has been adopted on 19th June 2013 and shall enter into force on 1st July 2013

RULES FOR THE CLASSIFICATION OF SHIPSPART 3

2013

REVIEW OF AMENDMENTS IN RELATION TO PREVIOUSEDITION OF THE RULES

RULES FOR THE CLASSIFICATION OF SHIPSPart 3 – HULL EQUIPMENT

All major changes throughout the text in respect to the Rules for the classification of ships, Part 3 – HullEquipment, edition 2012, forming the basis for this edition of the rules are shaded.

Items not being indicated as corrected have not been changed.

The grammatical and print errors, have also been corrected throughout the text of subject Rules but are notindicated as a correction.


2013

The subject Rules include the requirements of the following international Organisations:

International Maritime Organization (IMO)

Conventions: International Convention for the Safety of Life at Sea 1974 (SOLAS 1974) and all subsequentamendments up to and including the 2010 amendments (MSC.291(87))Protocol of 1988 relating to the International Convention for the Safety of Life at Sea 1974, asamended (SOLAS PROT 1988)International Convention for the Prevention of Pollution from Ships 1973, as modified by theProtocol of 1978 thereto (MARPOL 73/78) and all subsequent amendments up to and includingthe 2006 amendments (MEPC. 141(54))

International Association of Classification Societies (IACS)

Unified Requirements (UR): A1 (Rev.5, 2005), A2 (Rev.3, 2007), L4 (Rev.3, Corr.1 2011), M42 (Rev.4, 2011), S8 (Rev.4,2010), S9 (Rev.6, 2010), S10 (Rev.3, 2012), S21 (Rev.5, 2010), S21A (May 2011, Corr.1 Oct.2011), S26 (Rev.4, 2010), S27 (Rev.5, 2010)

Unified Recommendations: Rec.10 (Rev.2, 2005), Rec.13 (Rev.1, 2004), Rec.14 (Rev.2, Corr.1 2005), Rec.61 (2000),Rec.90 (2005), Rec.91 (Rev.1, 2011),

Unified Interpretations: LL20 (Rev.1, 2008), LL21 (Rev.1, 2008), LL62 (Rev.1, Corr.1, 2010), LL50 (Rev.5, 2008),LL70 (2005), SC113 (1996), SC138 (1998), SC153 (2000), SC156 (2000), SC190 (2004), SC191(Rev. 5, May 2013), SC212 (Corr.2, 2007), SC220 (Rev.1, 2010),


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Contents:Page

1 GENERAL .............................................................................................................................................................11.1 APPLICATION .......................................................................................................................................................................... 11.2 DEFINITIONS AND EXPLANATIONS................................................................................................................................... 11.3 SCOPE OF SUPERVISION....................................................................................................................................................... 21.4 PERMISSIBLE STRESSES ....................................................................................................................................................... 4

2 RUDDER ................................................................................................................................................................52.1 GENERAL.................................................................................................................................................................................. 52.2 MATERIALS ............................................................................................................................................................................. 52.3 RUDDER FORCE AND TORQUE............................................................................................................................................ 52.4 SCANTLINGS OF THE RUDDER STOCK.............................................................................................................................. 72.5 RUDDER STOCK COUPLINGS............................................................................................................................................... 92.6 RUDDER BEARINGS ............................................................................................................................................................. 102.7 RUDDER PINTLES................................................................................................................................................................. 112.8 RUDDER BODY...................................................................................................................................................................... 112.9 PROPELLER NOZZLES ......................................................................................................................................................... 132.10 REQUIREMENTS FOR THE SHIPS WITH ICE CLASS NOTATION ................................................................................. 13

3 ANCHORING ARRANGEMENT.....................................................................................................................143.1 GENERAL PROVISIONS ....................................................................................................................................................... 143.2 EQUIPMENT NUMBER ......................................................................................................................................................... 163.3 ANCHORS ............................................................................................................................................................................... 173.4 CHAIN CABLES AND ROPES FOR BOWER ANCHORS................................................................................................... 203.5 ANCHOR APPLIANCES ........................................................................................................................................................ 213.6 EQUIPMENT FOR SHIPS IN RESTRICTED AREA OF NAVIGATION............................................................................. 23

4 MOORING ARRANGEMENT..........................................................................................................................254.1 GENERAL PROVISIONS ....................................................................................................................................................... 254.2 MOORING ROPES.................................................................................................................................................................. 254.3 MOORING APPLIANCES ...................................................................................................................................................... 254.4 MOORING MACHINERY ...................................................................................................................................................... 26

5 TOWING ARRANGEMENT.............................................................................................................................275.1 GENERAL PROVISIONS ....................................................................................................................................................... 275.2 TOWING LINE........................................................................................................................................................................ 275.3 TOWING APPLIANCES ......................................................................................................................................................... 275.4 EMERGENCY TOWING ARRANGEMENTS ON TANKERS ............................................................................................. 275.5 SPECIAL ARRANGEMENT FOR TUGS............................................................................................................................... 295.6 SHIPBOARD FITTINGS AND SUPPORTING HULL STRUCTURES ASSOCIATED WITH TOWING AND MOORING305.7 EQUIPMENT FOR MOORING AT SINGLE POINT MOORINGS....................................................................................... 325.8 EMERGENCY TOWING PROCEDURES ON SHIPS ........................................................................................................... 33

6 SIGNAL MASTS .................................................................................................................................................346.1 GENERAL PROVISIONS ....................................................................................................................................................... 346.2 STAYED MASTS .................................................................................................................................................................... 346.3 UNSTAYED MASTS............................................................................................................................................................... 346.4 MASTS OF SPECIAL CONSTRUCTION .............................................................................................................................. 35

7 OPENINGS IN HULL, SUPERSTRUCTURES AND DECKHOUSES AND THEIR CLOSINGAPPLIANCES......................................................................................................................................................36

7.1 GENERAL PROVISIONS ....................................................................................................................................................... 367.2 SIDESCUTTLES AND WINDOWS........................................................................................................................................ 377.3 FLUSH SCUTTLES................................................................................................................................................................. 407.4 SHELL DOORS ....................................................................................................................................................................... 417.5 SUPERSTRUCTURES AND DECKHOUSES........................................................................................................................ 497.6 MACHINERY CASINGS ........................................................................................................................................................ 497.7 COMPANION HATCHES, SKYLIGHTS AND VENTILATING TRUNKS ......................................................................... 507.8 VENTILATORS....................................................................................................................................................................... 517.9 MANHOLES ............................................................................................................................................................................ 517.10 HATCHWAYS OF DRY CARGO HOLDS ............................................................................................................................ 517.11 HATCHWAYS OF CARGO TANKS IN TYPE "A" SHIPS................................................................................................... 787.12 OPENINGS IN WATERTIGHT SUBDIVISION BULKHEADS AND THEIR CLOSING APPLIANCES .......................... 787.13 STRENGTH AND SECURING OF SMALL HATCHES ON THE EXPOSED FORE DECK............................................... 82


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7.14 STRENGTH REQUIREMENTS FOR FORE DECK FITTINGS AND EQUIPMENT ...........................................................85

8 ARRAGNEMENT AND EQUIPMENT OF SHIP'S SPACES ........................................................................908.1 GENERAL PROVISIONS........................................................................................................................................................908.2 LOCATION OF SPACES.........................................................................................................................................................908.3 EQUIPMENT OF DRY CARGO HOLDS ...............................................................................................................................908.4 EXITS, DOORS, CORRIDORS, STAIRWAYS AND VERTICAL LADDERS .....................................................................918.5 GUARD RAILS, BULWARK AND GANGWAYS.................................................................................................................938.6 ACCESS TO THE CARGO AREA OF OIL TANKERS AND BULK CARRIERS................................................................94

RULES FOR THE CLASSIFICATION OF SHIPS 1PART 3

2013

1 GENERAL

1.1 APPLICATION

1.1.1 This Part of the Rules for the classification ofships (hereinafter referred to as: the Rules) applies to equip-ment, arrangements and outfit of sea-going ships sailing in adisplacement condition.

1.1.2 As to hydrofoil ships, hovercraft, and othersimilar ships, the requirements of this Part of the Rules are ap-plicable to the extent that is practicable and reasonable, andthe equipment, arrangements and outfit of these ships aresubject to special consideration by the CROATIAN REGIS-TER OF SHIPPING (hereinafter referred to as: the Register).

1.1.3 The application of this Part of the Rules to theinstallations and equipment of the sea-going ships, engaged innational navigation, with respect to the size of a ship (length,gross tonnage) and restricted area of navigation, may beagreed with the Register, on the case to case basis.

1.2 DEFINITIONS ANDEXPLANATIONS

Those relating to general terminology of theRules are given in Part 1 - General requirements, Chapter 1-General information.

1.2.1 Waterlines

1.2.1.1 Damage waterline - the waterline of a damagedship after flooding of corresponding separate compartments ortheir combinations as provided in the Rules, Part 5 - Subdivi-sion, 2.

1.2.1.2 Summer load waterline - the waterline the up-per edge of which passes through the centre of the ring of theload line mark when there is no fore-and-aft or athwart shipsinclination.

1.2.1.3 Summer timber load waterline - the waterlineindicated by the upper edge of the assigned summer timberload line.

1.2.1.4 Subdivision load waterline - the waterline usedin determining the subdivision of the ship.

1.2.1.5 Deepest subdivision load waterline - the sub-division load waterline which corresponds to the summerdraught to be assigned to the ship, see the Rules, Part 5 - Sub-division, 2.2.

1.2.2 Main dimensions

1.2.2.1 Length of ship (L) - the distance on the summerload waterline, in [m], from the fore side of stem to the afterside of the rudderpost, or the centre of the rudder stock if thereis no rudderpost. L is to be not less than 96% and need not ex-ceed 97% of the extreme length on the summer load waterline.In ships with unusual stem or stern arrangements, the length Lis to be specially considered.

1.2.2.2 Subdivision length of ship (Ls) - the length, in[m], measured between perpendiculars taken at the extremitiesof the deepest subdivision load line.

1.2.2.3 Draught of ship (d) - the vertical distance, in[m], measured amidships from the top of the plate keel, orfrom the intersection of the inner surface of the shell with thebar keel (the outer surface of a non-metal shell) to the summerload line.

1.2.2.4 Depth of ship (D) - the vertical distance, in [m],measured at amidships, from the top of the plate keel or fromthe intersection of the inner surface of the outer shell with thebar keel, to the top of the freeboard deck beams at sides.

On ships with rounded gunwales, moulded depthis taken to be the distance to the intersection of the continua-tion of a line extending from the level of the upper freeboarddeck and the outer edge of the side, as though the gunwalewere of angular design.

If the upper freeboard deck has longitudinalsteps and the raised part of the deck is above the point atwhich the lateral height of the ship is to be measured, the lat-eral height is measured up to the continuation of a line fromthe lower part of the deck and parallel to the upper part of thedeck at ship's sides.

1.2.2.5 Breadth of ship (B) - maximum breadth of ship,in [m], measured amidships from outside of frame to outsideof frame in a ship with metal shell and to the outer surface ofthe hull in a ship with a shell of any other material.

1.2.3 Superstructures and deckhouses

1.2.3.1 Superstructure - a decked structure on the free-board deck extending from side to side of the ship or with theside plating not being inboard of the shell plating more than0,04⋅B.

Superstructures may either be complete, i.e. ex-tending the full length of the ship L, or they may cover only acertain part of that length.

One or more tiers of such complete or detachedsuperstructures may be erected.

1.2.3.2 Deckhouse - a decked structure above thestrength deck the side plating being inboard of the shell plat-ing more than 0,04⋅B, with doors, windows, or other similaropenings in the outer bulkheads.

1.2.3.3 Trunk – a deck structure on the upper deck, notreaching at least one of the sides by a distance exceeding 4%of the breadth B and having no doors, windows or other simi-lar openings in the external bulkheads.

1.2.4 Tightness

1.2.4.1 Watertight - the term pertaining to closing ap-pliances of openings, which means that under specified pres-sure the liquid is not to penetrate through the closed openingsinto the ship.

1.2.4.2 Weathertight - the term pertaining to closingappliances of openings, which means that in any sea condi-tions water is not to penetrate through the openings inside theship. Such closing appliances shall withstand a hose test oncondition that the outlet of the nozzle is equal to or over 12

2 RULES FOR THE CLASSIFICATION OF SHIPSPART 3

2013

mm in diameter and the head in the hose provided for water jetejected upwards of not less than 0.2 MPa. The distance fromthe tested position is up to 1,5 m.

1.2.5 Decks

1.2.5.1 Upper deck - the uppermost continuous deckextending from fore to aft. The upper deck may be stepped.

1.2.5.2 Raised quarterdeck - the after upper part of astepped deck, the forward lower part of which is taken as aportion of freeboard deck.

1.2.5.3 Freeboard deck - the deck from which the free-board is measured.

In a ship having a deck with step, the lowest lineof this deck and the continuation of the line parallel to upperpart of the deck is taken as a freeboard deck.

1.2.5.4 Superstructure deckhouse or trunk deck - thedeck forming the top of a superstructure, deckhouse or trunk.

1.2.5.5 Superstructure decks of the first, second, etc.tiers - the decks forming the top of the superstructures of thefirst, second, etc. tiers, counting from the freeboard deck.

1.2.5.6 Bulkhead deck - the deck up to which the maintransverse watertight subdivision bulkheads are carried.

The bulkhead deck may be discontinuous, i.e.with step or steps formed both by main transverse watertightbulkheads reaching the keel and transverse watertight bulk-heads not reaching the keel.

1.2.5.7 Lower decks - the decks below the upper deck.

1.2.5.8 Weather deck - deck which is completely ex-posed to the weather from above and from at least two sides.

1.2.6 Amidships and perpendiculars

1.2.6.1 Amidships - at the middle of the ship's length L.

1.2.6.2 Forward and after perpendicular - the verticalline passing in the centre line at the fore and after end of theship's length L.

1.2.7 Type A and Type B ships

1.2.7.1 Type A ship - is one which:- designed to carry only liquid cargoes in

bulk.- has a high integrity of the exposed deck

with only small access openings to cargocompartments, closed by watertight gas-keted covers made of steel or an equivalentmaterial, and

- has low permeability of loaded cargocompartments.

Type A ship must also have certain other fea-tures, specified in the ICLL (International Convention on LoadLines, 1966, as amended).

1.2.7.2 Type B ship - a ship which does not meet re-quirements regarding Type A ships, and which is assigned afreeboard according to the ICLL, 1966.

1.2.8 Active means of the ship's steering - auxiliarymeans which develop a thrust at on angle of the centre lineplane of the ship of the zero or small speed, irrespective of theship's propulsive device operation and which are providedwith their own drive motor.

1.3 SCOPE OF SUPERVISION

1.3.1 General provisions on the ship's supervision,surveys and classification are given in the Rules, Part 1 - Gen-eral requirements, Chapter 1 – General information. Generalprovisions which apply to supervision during construction,surveys and classification of ships as well as provisions whichapply to technical documentation submitted to the Register arespecified in the Rules, Part 1 - General requirements, Chapter1 to Chapter 5.

1.3.2 The following items included into ship's equip-ment and arrangements are subject to the supervision duringtheir manufacture:

1.3.2.1 Rudder:.1 rudder stock,.2 rudder blade,.3 propeller nozzle,.4 rudder shafts.5 pintles of rudder and propeller nozzles,.6 pintle bushes,.7 fastenings (bolts and nuts with horizontal

flanged couplings and nuts with taperedcouplings, bolts and nuts for connectingthe rudder shaft and stern post),

.8 parts limiting deviation of the angle of therudder blade and rudder nozzle,

.9 rudder stock bearings,

.10 active means of ship steering.

1.3.2.2 Anchoring arrangement:.1 anchor,.2 chain cables or ropes,.3 anchor stoppers,.4 devices for securing and releasing the in-

board end of chain cable or rope,.5 anchor hawse pipes.

1.3.2.3 Mooring arrangement:.1 mooring ropes,.2 mooring bollards, belaying cleats, fair-

leads, chocks, rollers and stoppers.

1.3.2.4 Towing arrangement:.1 towing lines,.2 towing bollards, bits, fairleads, chocks,

and stoppers,.3 towing hooks and towing rails with fas-

tenings for their securing to ship's hull,.4 towing snatch-block.

1.3.2.5 Signal masts:.1 metal, non-metallic masts,.2 standing ropes,.3 permanent attachments to masts and decks

(eyeplates, hoops, etc.),


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.4 loose gear of masts and rigging (shackles,turnbuckles etc.).

1.3.2.6 Closing appliances of openings in hull,superstructures and deckhouses:.1 side and deck scuttles,.2 side shell doors,.3 doors in superstructures and deckhouses,.4 companion hatches, skylights and venti-

lating trunks,.5 ventilators,.6 manholes to deep and other tanks,.7 hatchway covers in dry cargo ships,.8 cargo tank hatchway covers in ships of

carriage of liquid cargoes in bulk,.9 doors in watertight subdivision bulkheads.

1.3.2.7 Equipment of ship's spaces:.1 ceiling and battens in cargo holds,.2 exit doors from ship's spaces in escape

routes,.3 stairways and vertical ladders,.4 guards rails, bulwarks and gangways.5 fixed and portable securing devices for

cargo securing.

1.3.3 Survey of the manufacture of the items specifiedin 1.3.2.1.6, 1.3.2.1.8, 1.3.2.1.9, 1.3.2.2.5, 1.3.2.3.2, 1.3.2.4.2,1.3.2.5, 1.3.2.6.5 and 1.3.2.7 is confined to consideration ofthe related technical documentation.

1.3.4 Where items specified in 1.3.2 are fitted the fol-lowing documents are to be submitted:

.1 assembly drawing,

.2 calculations,

.3 detail drawings if parts or assemblies arenot manufactured in accordance with ap-proved standards and specifications.

1.3.5 Materials for structural elements listed in Table1.3.5-1 are to be in accordance the requirements of the Rules,Part 25 - Metallic materials.

Materials for other items of equipment and ar-rangements, unless expressly provided otherwise in the Rules,shall meet the requirements specified in the design documen-tation approved by Register.

Welding of structural elements of ship's equip-ment is to be performed as specified in the Rules, Part 26 -Welding and Part 2 - Hull.

Table 1.3.5-1

No. ITEM MATERIAL

1. Rudder stocks and propellernozzles including theirflanges

Steel forgingsSteel castings

2. Parts of rudder Steel forgingsSteel castingsSteel platesSteel profiles

3. Rudder shafts, including theirflanges


4. Rudder pintles and pintle ofpropeller nozzles


5. Fastenings (bolts and nuts ofhorizontal flange couplingsand nuts for tapered cou-plings, bolts and nuts for con-nections of rudder shaft toflange couplings)

Steel forgings

6. Towing hooks for a force of10 kN and over, fastenings fortheir securing to ship's hull

Steel forgingsSteel platesSteel profiles

7.(1,2) Hatchways covers, side shelldoors

Steel platesSteel profilesLight alloy platesLight alloy profiles

8.(1,2) Sliding doors Steel forgingsSteel castingsSteel platesSteel profiles

9. Anchors Steel forgingsSteel castings

10. Chain cables Steel forgings

Notes:(1) The grades of rolled steel plates and profiles

are to be selected in accordance with theRules, Part 2 - Hull and Part 25 - Metallicmaterials,

(2) Welded structures and joints shall comply withthe Rules, Part 2 - Hull and Part 26 - Welding.

1.3.6 The following equipment and arrangements aresubject to survey while the ship is under construction:

.1 rudder,

.2 anchor arrangement,

.3 mooring arrangement,

.4 towing arrangement,

.5 masts and rigging,

.6 openings in the hull, superstructures anddeckhouses, and their closing appliances,

.7 arrangement and equipment of ship com-partments,

.8 fixed and portable securing devices forcargo securing,

.9 active means of ship's steering.


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1.4 PERMISSIBLE STRESSES

1.4.1 Wherever the working stresses are mentioned inthe text of this Part of the Rules, they mean equivalent stressescalculated from the formula:

22 3τσσ +=e, [N/mm2],

where:σe = equivalent stress, [N/mm2];σ = normal stress, [N/mm2];τ = shear stress, [N/mm2].

1.4.2 Permissible stresses with which the equivalentstresses are to be compared when verifying the strength con-ditions are established here in fractions of the yield point ReHof material used. The yield point is not to be taken as morethan 0,7 times the ultimate strength of material, unless ex-pressly stated otherwise.


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2 RUDDER

2.1 GENERAL

2.1.1 The following requirements apply to ordi-nary profile rudders. These requirements do not apply to CSRBulk Carriers.

2.1.2 For propeller nozzles see 2.9. For ice strength-ening see 2.10.

2.1.3 Rudder stock, rudder coupling, rudder bearings,pintles, rudder body are dealt with in this section. The steeringgear is to comply with the Rules, Part 9 – Machines, 6.2.

2.1.4 Structural details

2.1.4.1 Effective means are to be provided for support-ing the weight of the rudder without excessive bearing pres-sure by the rudder carrier attached to the upper part of the rud-der stock.

Hull structure in that area is to be adequatelystrengthened.

2.1.4.2 Suitable arrangements are to be provided to pre-vent the rudder from lifting.

2.1.4.3 In rudder trunks, which are open to the sea, aseal of stuffing box is to be fitted above the deepest load wa-terline, to prevent water from entering the steering gear com-partment and lubricant from being washed away from the rud-der carrier. If the top of rudder trunk is below the deepest wa-terline two separate stuffing box are to be provided.

2.1.5 Rudder area

In order to achieve sufficient manoeuvring capa-bility the size of the movable rudder area is recommended tobe not less than obtained from the following formula:

A = 0.0175 ⋅ C1 ⋅ C2 ⋅ C3 ⋅C4 ⋅ L ⋅ d, [m2]

where:

C1 - factor depending upon the ship type:= 0.9 for tankers and bulk carriers hav-

ing a displacement of more than50 000 t;

= 1.7 for tugs and trawlers= 1.0 for other ships;

C2 - factor for the rudder type:= 0.9 for semi-spade rudders= 0.8 for double rudders (per rudder)= 1.0 for other type;

C3 - factor depending upon the= 1.0 for NACA-profiles and plate rud-

der= 0.8 for hollow profiles

C4 - factor depending upon the rudder ar-rangement

= 1.0 for rudders in the propeller jet= 1.5 for rudders outside the propeller

jet.

For semi-spade rudders 50% of the projectedarea of the rudder horn may be included into rudder area.

2.2 MATERIALS

2.2.1 Rudder stocks, pintles, coupling bolts keys andcast parts of rudders are to be made of rolled, forged or castcarbon manganese steel in accordance with the Rules, Part 25- Metallic materials, 3.

For rudder stock, pintles, keys and bolts theminimum yield stress is not to be less than 200 N/mm2.

If material is used having ReH differing from 235N/mm2, the material factor is to be determined as follows:

eeHR

k

=

235,

where:e = 0.75 for ReH > 235 N/mm2;e = 1.00 for ReH ≤ 235 N/mm2

ReH = minimal nominal upper yield point ofmaterial used, in [N/mm2], is not to betaken greater than 0.7⋅Rm or 450N/mm2, whichever is less.

Rm = tensile strength of the material, in[N/mm2].

2.2.2 Before significant reductions in rudder stock di-ameter due to application of steel with Reh exceeding 235N/mm2 are granted, the Register may require the evaluation ofthe rudder stock deflection. Large deflections are to beavoided in order to avoid excessive edge pressures in way ofbearings.

2.2.3 Welded parts of rudders are to be made of ap-proved rolled hull materials. Required scantlings may be re-duced when higher tensile steels are applied. The materialfactor according to the Rules, Part 2-Hull, 1.4 is to be used.

2.3 RUDDER FORCE ANDTORQUE

2.3.1 Rudder blades without cut-outs(see Fig. 2.3.1.1)

2.3.1.1 The rudder force upon which the rudder scant-lings are to be based is to be determined according to the fol-lowing formula:

CR = 132 ⋅ A ⋅ ν2 ⋅ k1 ⋅ k2 ⋅ k3 ⋅ ktwhere:

CR - rudder force, in [N];A - area of rudder blade, in [m2]ν - maximum service speed, in [knots], with

ship on summer load waterline. When thespeed is less than 10 knots, ν is to be re-placed by the expression:

νmin = ( )320+ν ;

For the astern condition the maximum asternspeed is to be used, however, in no case less than:

vastern = 0.5⋅νk1 = factor depending on the aspect ratio Λ;


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k1 = (Λ + 2)/3, with Λ not to be takengreater than 2;

Λ =tA

b2, where b = mean height of the rudder

area, in [m]. Mean breadth and meanheight of rudder are calculated accordingto Fig. 2.3.1.1.

At = sum of rudder area A and area of rudderpost or rudder horn, if any, within theheight b, in [m2];

k2 = factor depending on the type of the rudderprofile according to Table 2.3.1.1-1;

k3 = 0,8 for rudders outside the propeller jet;1,15 for rudders aft of the propeller nozzle;1,0 elsewhere, including also rudderswithin the propeller jet.

221 xxc +

=cAb =

Figure 2.3.1.1

Table 2.3.1.1-1

k2Profile / type of rudder Aheadcondition

Asterncondition

NACA.00Gottingen-profiles 1,1 0,80

Hollow profiles

1,35 0,90

Flat profiles

1,1 0,90

kt = coefficient depending on the thrust co-efficient CTh

= 1,0 normallyIn special cases for thrust coefficients CTh

> 1,0 determination of kt according to thefollowing formula may be required:

)0.1()(

==

ThR

ThRt CC

CCk

2.3.1.2 Rudder torque

The rudder torque is to be calculated for both theahead and astern condition according to the formula:

QR = CR ⋅ r, in [Nm]where:

r = c (α - KA), in [m];c = mean breadth of rudder area, in [m],

(see. Fig. 2.3.1.1);α = 0,33 for ahead condition;α = 0,66 for astern condition;

AA

K fA = ,

where:Af = portion of the rudder blade area situ-

ated ahead of the centre line of therudder stock

For ahead condition r is not to be taken lessthan:

0,1 ⋅ c

2.3.2 Rudder blades with cut-outs(semi-spades rudders)

2.3.2.1 The total rudder force is to be calculated ac-cording 2.3.1.1. The pressure distribution over the rudder area,upon which the determination of rudder torque and rudderblade strength are to be based, is to be derived as follows:

The rudder area may be divided into two rectan-gular or trapezoidal parts with areas A1 and A2, so thatA=A1+A2 (see fig. 2.3.2).

Figure 2.3.2

The levers r1 and r2 are to be determined as fol-lows:

r1 = c1 (α - K1), in [m];r2 = c2 (α - K2), in [m];


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K1 =1

1

AA f ;

1

11 b

Ac =

K2 =2

2

AA f ;

2

22 b

Ac = ;

α = 0,33 for ahead conditionα = 0,66 for astern conditionFor parts of rudder behind a fixed structure such

as rudder horn:α = 0,25 for ahead conditionα = 0,55 for astern conditionThe resulting force of each part may be taken as:

CR1 =AACR

1⋅ , [N]

CR2 =AACR

2⋅ , [N]

2.3.2.2 The resulting torque of each part may be takenas:

QR1 = CR1 ⋅ r1 , [Nm]

QR2 = CR2 ⋅ r2 , [Nm]

2.3.2.3 The total rudder torque is to be determined ac-cording to the following formula:

QR = QR1 + QR2 , [Nm]

For ahead condition QR is not to be taken lessthan:

QRmin = 0,1 ⋅ CR ⋅A

cAcA 2211 ⋅+⋅

2.4 SCANTLINGS OF THERUDDER STOCK

2.4.1 The diameter of rudder stock

2.4.1.1 The rudder stock diameter for the transmissionof the rudder torque in way of the tiller not to be less than:

32.4k

Qd Rt ⋅= , [mm]

where:QR = total rudder torque, in [Nm], as calculated

according 2.3.The rudder stock diameter required for the

transmission of the rudder torque is to be dimensioned suchthat the torsional stress is not to exceed the following value:

τt = 68 ⋅ kFor the material factor k, see 2.2.

2.4.1.2 If the rudder stock is subjected to combinedtorque and bending the equivalent stress in the rudder stock isnot to exceed 118 ⋅ k.

The equivalent stress is to be determined by theformula:

22 3 tbe τσσ += , [N/mm2]

Bending stress:

3

3102,10

cb

d

M⋅⋅=σ , [N/mm2]

Torsional stress:

3

3101,5

c

Rt d

Q⋅⋅=τ , [N/mm2]

The rudder stock diameter is not to be less than:

62

341

+⋅=

Rtc Q

Mdd , [mm],

where:M = bending moment, in [Nm], at the section of

the rudder stock considered.The diameter dc is decisive for the scantlings of

the coupling.

2.4.1.3 When calculating the diameter of the rudderstock, cognizance must be taken of SOLAS II-1/29.3.3 and29.4.3.

In this regard, the diameter mentioned in SOLASII-1/29.3.3, 29.4.3 and 29.14 should be taken as having beencalculated for rudder stock of mild steel with a yield strengthof 235 N/mm2 (i.e. with a material factor k=1).

See also IACS unified interpretation SC153.

2.4.2 Calculation of bending moment and shearforce distribution

2.4.2.1 The rudder force and resulting rudder torque asgiven in 2.3 causes bending moments and shear forces in therudder body, bending moments and torques in the rudderstock, supporting forces in pintle bearings and rudder stockbearings and bending moments, shear forces and torques inrudder horns and heel pieces. The rudder body is to be stiff-ened by horizontal and vertical webs enabling it to act asbending girder.

2.4.2.2 The bending moments, shear forces and torquesas well as the reaction forces are to be determined by a directcalculation or by an approximate simplified method according2.4.2.5. For rudders supported by sole pieces or rudder hornsthese structures are to be included in the calculation model inorder to account for the elastic support of the rudder body.Guidelines for calculation of bending moment and shear forcedistribution are given in 2.4.2.3 to 2.4.2.5.

2.4.2.3 Data for the analysis

The standard data to be used for direct calcula-tion are as follows:l10 ÷ l50 - lengths of the individual girders of the system, [m];I10 ÷ I50 - moments of inertia of these girders, [cm4].

For rudders supported by a sole piece the lengthl20 is the distance between lower edge of rudder body andcentre of sole piece, and I20 is the moment of inertia of thepintle in sole piece.

Load acting on rudder body (general):

310 10⋅

=l

CP R

R , [kN/m]

Load for semi-spade rudders:


2013

310

210 10⋅

=l

CP R

R , [kN/m]

320

120 10⋅

=l

CP R

R , [kN/m],

where:CR, CR1, CR2 , see 2.3;Z = spring constant of support in the sole piece

or rudder horn respectively;

Z =350

5018,6l

I⋅ , in [kN/m], for support in sole

piece;I50 = moment of inertia of sole piece around the

Z-axis, in [cm4];l50 = effective length of sole piece, in [m];

Z =tb ff +

1, in [kN/m], for the support in

the rudder horn (Fig. 2.4.2.5.2);fb = unit displacement of rudder horn, in [m],

due to a unit force of 1kN acting in thecentre of support;

fb =nI,

d,⋅186

313

, in [kN/m], (guidance value);

In = moment of inertia of rudder horn aroundthe x-axis at distance d/2, in [cm4], (seealso Fig. 2.4.2.5.2.);

ft = unit displacement due to torsion;

ft = 28

2

1014,3/

T

ii

Ftued

⋅⋅

Σ⋅⋅, in [m/kN];

FT = mean sectional area of rudder horn, [m2];ui = breadth, in [mm], of the individual plates

forming the mean horn sectional area;ti = plate thickness within the individual

breadth, in [mm];e,d = see Fig. 2.4.2.5.2.

2.4.2.4 Moments and forces to be evaluated

The bending moment MR and the shear force Q1in the rudder body, the bending moment Mb in the neck bear-ing and the support forces B1, B2 and B3 are to be evaluated.

2.4.2.5 Guidance values for some basic rudder types

In Fig. 2.4.2.5.1 to 2.4.2.5.3 are given formulaefor moments and forces according simplified method.

RR C

lBM⋅

⋅=

210

21 [Nm]

Mb = B3 l40 [Nm]

( )3010

30101

5,0ll

llCB R

++⋅

= [N]

B2 = CR - 0.8 B1 + B3 [N]

( )( )40301040

23010

3 8 llllllCB R

+++

= [N]

Figure 2.4.2.5.1Rudder supported by sole piece


2013

2102 lCM R

R⋅

= [Nm]

( )3020

210

10 lllCM R

b +⋅

= [Nm]

30201 ll

bCB R

+⋅

= [N]

B2 = CR - B1; B2 min = CR/4 [N]

403 l

MB b= , Q1 = CR2 [N]

Figure 2.4.2.5.2Semi-spade rudder

( )( )

+

++=

21

211020 3

2xx

xxllCM RB

[Nm]

303 l

MB B= [N]

B2 = CR + B3 [N]

Figure 2.4.2.5.3Spade rudder

2.5 RUDDER STOCK COUPLINGS

2.5.1 General

2.5.1.1 The couplings are to be designed in such a wayas to enable them to transmit the full torque of the rudderstock.

2.5.1.2 The distance of the bolt axis from the edges ofthe flange is not to be less than 1,2 times the diameter of thebolt. In horizontal couplings, at least 2 bolts are to be arrangedforward of the stock axis.

2.5.1.3 The coupling bolts are to be fitted bolts. Thebolts and nuts are to be effectively secured against loosening.

2.5.1.4 For spade rudders horizontal couplings accord-ing to 2.5.2 are permissible only where the required thicknessof the coupling flanges tf is less than 50 mm, otherwise conecouplings according to 2.5.4 are to be applied. For spade rud-ders of the high lift type, only cone couplings according to2.5.4 are permitted.

2.5.1.5 If a cone coupling is used between the rudderstock or pintle, as the case can be, and the rudder blade orsteering gear (see 2.5.4), the contact area between the matingsurfaces is to be demonstrated to the Surveyor by blue print


2013

test and should not be less than 70 % of the theoretical contactarea (100 %).

Non-contact areas should be distributed widelyover the theoretical contact area. Concentrated areas of non-contact in the forward regions of the cone are especially to beavoided. The proof has to be demonstrated using the originalcomponents and the assembling of the components has to bedone in due time to the creation of blue print to ensure thequality of the surfaces. In case of storing over a longer period,sufficient preservation of the surfaces is to be provided for.

2.5.2 Horizontal couplings

2.5.2.1 The diameter of the coupling bolts is not to beless than:

bmb ken

kd,d⋅⋅

⋅⋅=

3620 , [mm]

where:d = stock diameter, the greater of the diameters

dt or dc according to 2.4.1.1 and 2.4.1.2, in[mm];

n = total number of bolts, which is not to beless than 6;

em = mean distance of the bolt axes from thecentre of bolt system, in [mm];

k = material factor for the rudder stock;kb = material factor for the bolts (see 2.2).

2.5.2.2 The thickness of the coupling flanges is not to beless than determined by the following formula:

b

fbf k

kdt ⋅= , [mm]

tfmin = 0.9 ⋅ db , [mm];where:

kf = material factor for the coupling flanges(see 2.2)

db = bolt diameter calculated for a number ofbolts not exceeding 8.

2.5.2.3 The width of material outside the bolt holes isnot to be less than 0.67⋅db.

2.5.3 Vertical couplings

2.5.3.1 The diameter of coupling bolts is not to be lessthan:

kk

ndd b

b⋅

=81.0 [mm];

For d, k, kb, see 2.5.2.1, where n is number ofbolts (less than 8 is not to be taken).

2.5.3.2 The first moment of area of the bolts about thecentre of the coupling, m, must be at least:

m = 0,00043⋅d3 [cm3], d in [cm]

2.5.3.3 The thickness of the coupling flanges must be atleast equal to the bolt diameter, and the width of the flangematerial outside the bolt holes must be greater than or equal to0.67⋅db.

2.5.3.4 For the connection of the coupling flanges withthe rudder body see also Rules, Part 2, 15.2.4.4.

2.5.4 Cone couplings

2.5.4.1 Cone couplings without hydraulic arrangementsfor mounting and dismounting the coupling should have a ta-per on diameter of 1:8-1:12 and be secured by a slugging nut.

taper = l

dd uo −, see Fig .2.5.4

Figure 2.5.4

The taper length (l) of rudder stock fitted intorudder blade and secured by a nut is generally not to be lessthan 1.5 times do.

2.5.4.2 For couplings between rudder stock and rudder akey is to be provided. Scantlings of the key are to be speciallyconsidered by the Register.

2.5.4.3 The dimensions of the slugging nut are to be asfollows (see Fig. 2.5.4):

- external thread diameter: dg ≥ 0,65 ⋅ do- height of nut: hn ≥ 0,6 dg- outer diameter of nut: dn ≥ 1,2 ⋅ du or 1,5 dg

(whichever is the greater)

2.5.4.4 Cone coupling with hydraulic arrangements (oilinjection and hydraulic nut) for mounting and dismounting thecoupling is to have a taper on diameter of 1:12 -1:20.

The push-up oil pressure and the push-up lengthare to be specially considered in each individual case based ona calculation to be submitted by the shipyard.

2.6 RUDDER BEARINGS

2.6.1 General

In way of bearings liners and bushes are to befitted. Where in case of small ships bushes are not fitted, the


2013

rudder stock is to be suitably increased in diameter in way ofbearings enabling the stock to be re-machined.

The reaction force in bearing is to be determinedaccording 2.4.2. An adequate lubrication is to be provided.

2.6.2 Minimum bearing surface

An adequate lubrication is to be ensured.The bearing surface Ab (defined as the projected

area: length x outer diameter of liner) is not to be less than:

ab q

PA = [mm2]

where:P - reaction force, in [N], in bearing as deter-

mined in 2.4.2;qa - allowable surface pressure according to the

Table 2.6.2-1.The maximum surface pressure qa for the various combina-tions is to be taken as reported in the table below. Higher val-ues than given in the table may be taken in accordance withmakers’ specifications if they are verified by tests.

Table 2.6.2-1

Bearing material qa [N/mm2]

lignum vitae 2.5white metal, oil lubricated 4.5synthetic material with hardness between 60and 70 Shore D1) 5.5

Steel 2), bronze and hot-pressed bronze-graphite materials 7.0

Notes:1) Indentation hardness test at 23°C and with 50% mois-

ture, according to a recognised standard.Synthetic bearing materials is to be of approved type.

2) Stainless and wear-resistant steel in an approved com-bination with stock liner.

2.6.3 Length of bearings

The bearing length is to be equal to the bearingdiameter, however, is not to exceed 1.2 times the bearing di-ameter but is not to be less than diameter.

2.6.4 Bearing clearances

Where metal bearing clearances are not to be

less than 011000

,db + mm on the diameter.

db = internal diameter of bush, in [mm].If non-metallic bearing material is applied, the

bearing clearance is to be specially determined considering thematerial's swelling and thermal expansion properties. Thisclearance is not to be taken less than 1.5 mm on bearing di-ameter unless a smaller clearance is supported by the manu-facturer’s recommendation and there is documented evidenceof satisfactory service history with a reduced clearance.

2.7 RUDDER PINTLES

2.7.1 Pintles are to have scantlings complying withconditions given in 2.6.2 to 2.6.4.

2.7.2 The pintle diameter is not to be less than:

kB

.d ip 350= [mm]

where:Bi = relevant bearing force determined accord-

ing 2.4.2 in [N];k = material factor as given in 2.2.

2.7.3 The length of the pintle housing in the gudgeonis not to be less than the maximum pintle diameter dp.

2.7.4 The minimum dimensions of threads are to bedetermined according to 2.5.4.3.

2.7.5 Pintles are to have a conical attachment to thegudgeons with a taper on diameter not greater than:

- 1:8 - 1:12 for keyed and other manually as-sembled pintles applying locking by slug-ging nut;

- 1:12 - 1:20 on diameter for pintles mountedwith oil injection and hydraulic nut.

2.7.6 For recommended maximum allowable rudderpintle clearance see IACS Rec. No.61.

2.8 RUDDER BODY

2.8.1 General

2.8.1.1 The rudder body is to be stiffened by horizontaland vertical webs in such manner that rudder body is to be ef-fective as a beam.

2.8.1.2 Single plate rudders may be applied to smallervessels with service restrictions.

2.8.1.3 It is recommended to keep the natural frequencyof the fully immersed rudder at least 10% above the excitingfrequency of the propeller.

2.8.1.4 Rudder body is to be watertight.

2.8.2 Rudder blade strength

2.8.2.1 The strength of the rudder body is to be provedaccording to 2.4.2.

2.8.3 Permissible stresses

2.8.3.1 For rudder bodies without cut-outs the permissi-ble stresses are determined as follows (see Fig. 2.3.1.1):

- bending stress:σ ≤ 110 N/mm2

- shear stress:τ ≤ 50 N/mm2

- equivalent stress:


2013

1203 22 ≤+= τσσ e N/mm2

2.8.3.2 For rudder bodies with cut-outs (e.g. semi-spaderudders, see Fig. 2.3.2):

- bending stress:σ ≤ 75 N/mm2

- shear stress:τ ≤ 50 N/mm2

Equivalent stress in way of cut-outs:

1003 22 ≤+= τσσ e N/mm2

Bending moment is to be calculated as follows:

22

112fBfCM RR ⋅+⋅= , [Nm]

Shear force may be calculated as follows:Q1 = CR2 , [N]

where:f1, f2 - according to Fig. 2.8.3.2;CR2 - partial rudder force, in [N], of the par-

tial rudder area A2 bellow the cross-section under consideration.

e - lever for torsion moment, in [m]; it is ahorizontal distance between distanceof area A2 and the centre linea-a of the effective cross sectional areaunder consideration (see Fig. 2.8.3.2).

The centroid may be assumed at 0.33 c2 aft ofthe forward edge of area A2.

Figure 2.8.3.2The torsion stress may be calculated in simpli-

fied manner as follows:

thlM t

t ⋅⋅⋅=

2τ [N/mm2]

where:Mt = CR2 ⋅ e;l,h,t - see Fig. 2.8.3.2.

2.8.3.3 The distance l between the vertical webs is notto exceed 1,2 ⋅ h.

The radii in the rudder plating are not to be lessthan 4 – 5 times the plate thickness, but in no case less than 50mm.

2.8.4 Rudder plating

The thickness of the rudder side, top and bottomplating is not to be less than:

5.2105.54

++⋅⋅⋅=−

ACdst Rβ , [mm]

where:d - summer load line draught, in [m];CR - rudder force, in [N], according 2.3;A - rudder are, in [m2];

β =2

5011

−

bs.. ; max 1.0, if b/s ≥ 2,5;

s - smallest unsupported width of plating, in[m];

b - greatest unsupported with plating in [m];For higher tensile steels the material factor ac-

cording to the Rules, Part-2, Hull, 1.4 is to be used corre-spondingly.

The thickness is not to be less than the minimumthickness of the bottom plating according to the Rules, Part 2 -Hull, 5.2.

The thickness of the nose plates may be in-creased to the discretion of the Register.

2.8.5 Rudder webs

The thickness of the webs is not to be less than70% of the thickness of the rudder plating, however, not lessthan:

ktmin

8= , [mm]

2.8.6 Welding

For connecting the side plating of the rudder tothe webs, where fillet welding is not practicable, the sideplating is to be connected by means of slot welding to flatbars, which are welded to the webs.

The length of the slots is not to be less than 75mm and breadth is not to be less two times rudder plate thick-ness, with distance of 125 mm between ends of slots.

Plate edges at corners in cut-outs are to berounded.

2.8.7 Single plate rudders

2.8.7.1 The mainpiece diameter is to be calculated ac-cording to 2.4. For spade rudders the lower third may be ta-pered down to 0,75 times stock diameter.

2.8.7.2 The blade thickness is not to be less than:

tB = 1,5 ⋅ s ⋅ v + 2,5, [mm],where:

s = spacing of stiffening arms, in [m]; not toexceed 1 m;

V = speed of ship, in [knots]; (see 2.3.1.1)

2.8.7.2 The thickness of the arms is not to be less thanthe blade thickness: ta = tb.


2013

The section modulus is not to be less than:Za = 0.5 s C1

2 V2, in [cm3];C1 = horizontal distance from the aft edge

of the rudder to the centreline of therudder stock, in [m].

For higher tensile steels the material factor ac-cording to the Rules, Part-2, Hull, 1.4 is to be used corre-spondingly.

2.9 PROPELLER NOZZLES

2.9.1 General

The following requirements are applicable topropeller nozzles having an inner diameter up to 5 m.

Special attention is to be given to the support offixed nozzles at the hull structure.

2.9.2 Design pressure

The design pressure for propeller nozzles is to bedetermined by the following formula:

pd = c ⋅ p, [kN/m2]where:

P

S

APp ε= , [kN/m2];

Ps = maximum shaft power, in [kW];Ap = propeller disc area, in [m2];

=4

2 π⋅D

D = propeller diameter, in [m];ε = factor according to the following for-

mula:

P

S

AP410221.0 −⋅−=ε

εmin = 0,1;c = 1,0 in zone 2;c = 0,5 in zones 1 and 3;c = 0,35 in zone 4For nozzle zones see Fig. 2.9.2.

Figure 2.9.2

2.9.3 Plate thickness

2.9.3.1 The thickness of the nozzle shell plating is not tobe less than:

5.25 +⋅⋅= dpst , [mm]

tmin = 7,5 mmwhere:

s = spacing of ring stiffeners, in [m]

2.9.3.2 The web thickness of the internal stiffening ringis not to be less than the nozzle plating for zone 3, however, inno case be less than 7,5 mm.

2.9.4 Section modulus

The section modulus of the cross section shownin Fig. 2.9.2 around its neutral axis is not to be less than:

W = n ⋅ d2 ⋅ b ⋅ v2 , [cm3]

where:d - inner diameter of nozzle, in [m];b - length of nozzle, in [m],n = 0,7 for fixed nozzles;n = 1,0 for rudder nozzles;v = speed of ship according 2.3.

2.9.5 Welding

The inner and outer nozzle shell plating is to bewelded to the internal stiffening rings as far as practicable bydouble continuous welds. Plug welding is only permissible forthe outer nozzle plating.

2.10 REQUIREMENTS FOR THESHIPS WITH ICE CLASS NOTATION

2.10.1 When calculating the rudder force and torsionmoment according 2.3, the ships speed v is not to be taken lessthan the values specified in Table 2.10.1-1.

Table 2.10.1-1

Ice class notation v [knots]

1AS 20

1A 18

1B 16

1C, 1D 14

If the actual speed of ship is greater than valuegiven in Table 2.10.1-1 actual ship's speed is to be taken intoaccount.

Within the ice belt the thickness of the rudderplating is to be determined as the shell plating within aft re-gion of the ice belt. For regions of ice belt see the Rules, Part2- Hull, 14.1.

2.10.2 For the ships with ice class notations 1AS and1A the rudder stock and upper edge of the rudder are to beprotected against ice pressure by an ice knife or equivalentmeans.

2.10.3 It is recommended that the gap between rudderbody and ship's shell is not to be less than 50 mm or 5% of therudder body thickness, whichever is greater.


2013

3 ANCHORING ARRANGEMENT

3.1 GENERAL PROVISIONS

3.1.1 The anchoring equipment required herewith isintended for temporary mooring of a vessel within a harbouror sheltered area when the vessel is awaiting bert, tide, etc.

3.1.2 The equipment is therefore not designed to holda ship off fully exposed coasts in rough weather or to stop aship, which is moving or drifting. In this condition the loadson the anchoring equipment increase to such a degree that itscomponents may be damaged or lost owing to the high energyforces generated, particularly in large ships.

3.1.3 The anchoring equipment presently requiredherewith is designed to hold a ship in good holding ground in

conditions such as to avoid dragging of the anchor. In poorholding ground the holding power of the anchors is to be sig-nificantly reduced.3.1.4 The Equipment Numeral (En) formula for an-choring equipment required hereunder is based on followingassumptions: current speed of 2.5 m/sec, wind speed of 25m/sec and scope of chain cable between 6 and 10, the scopebeing the ratio between length of chain paid out and waterdepth.3.1.5 It is assumed that under normal circumstances aship will use only one bow anchor and chain cable at a time.3.1.6 For all ships of unrestricted service, exceptfishing vessels, the equipment for anchoring, mooring andtowing is to be selected from Table 3.1.2-1, and for fishingvessels from Table 3.1.2-2.

Table 3.1.2-1Equipment

numeralStockless

anchor Stud link chain cables Stream wireor chain

Towing line**/ Mooring line

Bower anchor Diameter

Equi

pmen

t let

ter

Exc.

Not

exc

.

No.

Mas

s per

an-

chor

Stre

am a

ncho

r

Tota

l len

gth

Ord

inar

y qu

ality

CR

S-L1

Spec

. qua

lity

CR

S-L2

Extra

spec

. qua

l-ity

CR

S-L3

Leng

th

Bre

akin

g lo

ad

Leng

th

Bre

akin

g lo

ad

No.

Leng

th o

f eac

h lin

e

Bre

akin

g lo

ad

[kg] [kg] [m] [mm] [mm] [mm] [m] [kN] [m] [kN] [m] [kN]

A1A2A3

101520

152025

222

355065

--

110137,5165

*/-

---

---

---

---

---

---

222

303040

292929

A4A5A6

253040

304050

222

80105135

-3545

165192,5192,5

1111

12,5

---

---

-5570

-5560

-120150

-6581

222

505060

292929

A7A8A9

507090

7090

110

222

180240300

6080

100

220220

247,5

1416

17,5

12,51416

---

808585

657481

180180180

989898

333

80100110

343739

B1B2B3

110130150

130150175

222

360420480

120140165

247,5275275

1920,522

17,517,519

---

909090

8998

108

180180180

989898

333

110120120

444954

B4B5B6

175205240

205240280

233

570660780

190--

302,5302,5330

242628

20,52224

-20,522

90--

118 180180180

112129150

344

120120120

596469

B7B8B9

280320360

320360400

333

90010201140

---

357,5357,5385

303234

262830

242426

---

--

180180180

174207224

444

140140140

747888

C1C2C3

400450500

450500550

333

129014401590

---

385412,5412,5

363840

323434

283030

---

---

180180190

250276306

444

140140160

98108123

C4C5C6

550600660

600660720

333

174019202100

440440440

424446

363840

323436

190190190

338371406

444

160160160

132147157

C7C8C9

720780840

780840910

333

228024602640

467,5467,5467,5

485052

424446

363840

190190190

441480510

444

170170170

172186201

D1D2D3

9109801060

98010601140

333

285030603300

495495495

545658

485050

424446

190200200

559603647

444

170180180

216230250

* /Chain cables or wire ropes may be used, chain cable breaking load or actual breaking strength of rope being not less than 44 kN.** /Towing lines are recommendations only.


2013

Table 3.1.2-1 - continued

Equipmentnumeral

Stocklessanchor Stud link chain cables Stream wire

or chainTowing line

**/ Mooring line

Bower anchor Diameter

Equi

pmen

t let

ter

Exc.

Not

exc

.

No.

Mas

s per

an-

chor

Stre

am a

ncho

r

Tota

l len

gth

Ord

inar

y qu

ality

CR

S-L1

Spec

. qua

lity

CR

S-L2

Extra

spec

. qua

l-ity

CR

S-L3

Leng

th

Bre

akin

g lo

ad

Leng

th

Bre

akin

g lo

ad

No.

Leng

th o

f eac

h lin

e

Bre

akin

g lo

ad

[kg] [kg] [m] [mm] [mm] [mm] [m] [kN] [m] [kN] [m] [kN]

D4D5D6

114012201300

122013001390

333

354037804050

522,5522,5522,5

606264

525456

464850

200200200

691738786

444

180180180

270284309

D7D8D9

139014801570

148015701670

333

432045904890

550550550

666870

586062

505254

200220220

836888941

455

180190190

324324333

E1E2E3

167017901930

179019302080

333

525056106000

577,5577,5577,5

737678

646668

565860

220220220

102411091168

555

190190190

353378402

E4E5E6

208022302380

223023802530

333

645069007350

605605605

818487

707376

626466

240240240

125913561453

555

200200200

422451480

E7E8E9

253027002870

270028703040

333

270083008700

---

632,5632,5632,5

909295

788184

687073

---

---

260260260

147114711471

666

200200200

480490500

F1F2F3

304032103400

321034003600

333

93009900

10500

---

660660660

97100102

848790

767878

---

---

280280280

147114711471

666

200200200

520554588

F4F5F6

360038004000

380040004200

333

111001170012300

---

687,5687,5687,5

105107111

929597

818487

---

---

300300300

147114711471

667

200200200

618647647

F7F8F9

420044004600

440046004800

333

129001350

14100

---

715715715

114117120

100102105

879092

---

---

300300300

147114711471

777

200200200

657667677

G1G2G3

480050005200

480050005200

333

147001540016100

---

742,5742,5742,5

122124127

107111111

959797

---

---

300300300

147114711471

788

200200200

686686696

G4G5G6

550058006100

580061006500

333

169001780018800

---

742,5742,5742,5

130132

-

114117120

100102107

---

---

300300300

147114711471

899

200200200

706706716

G7G8G9

650069007400

690074007900

333

200002150023000

---

770770770

---

124127132

111114117

---

---

91011

200200200

726726726

H1H2H3H4

7900840089009400

840089009400

10000

3333

24500260002750029000

----

770770770770

--

137142147152

122127132132

----

----

11121314

200200200200

736736736736

H5H6H7

100001070011500

107001150012400

333

310003300035500

---

770770770

---

---

137142147

---

---

151617

200200200

736736736

H8H9I1

124001340014600

134001460016000

333

385004200046000

---

770770770

---

---

152157162

---

--

Towing linesare not re-

quired whenship length ex-ceeds 180 m.

181921

200200200

736736736

* /Chain cables or wire ropes may be used, chain cable breaking load or actual breaking strength of rope being not less than 44 kn.** /Towing lines are recommendations only.


2013

Table 3.1.2-2

Equipment number Bower stockless Stud link chain cables for anchors Mooring lineDiameterEquipment

letter Exceeding Notexceeding Number Mass

anchorTotallength

ordinaryquality

CRS-L1

specialquality

CRS-L2

Number Length ofeach line

Actualbreakingstrength

[kg] [m] [mm] [mm] [m] [kN]

a1a2a3

3040

to 304050

222

7080100

137,5165

192,5

*/11,011,0

---

222

405060

252929

a4a5a6

506070

607080

222

120140160

192,5192,5220

12,512,514

--

12,5

222

6080100

292934

a7a8a9

8090100

90100110

222

180210240

220220220

141616

12,51414

222

100110110

373739

b1b2b3

110120130

120130140

222

270300340

247,5247,5275

17,517,519

1616

17,5

222

110110120

394444

b4b5b6

140150175

150175205

222

390480570

275275

302,5

192224

17,519

20,5

222

120120120

495459

b7b8b9

205240280

240280320

222

660780900

302,5330

357,5

262830

222426

233

120120140

647178

c1c2c3

320360400

360400450

222

102011401290

357,5385385

323436

283032

333

140140140

8593100

c4c5c6

450500550

500550600

222

144015901740

412,5412,5440

384042

343436

344

140160160

108113118

c7c8

600660

660720

22

19202100

440440

4446

3840

44

160160

123128

* /Chain cables or wire ropes may be used, cable breaking load or actual breaking strength of wire rope being no less than 44 kN.

3.1.7 When determining the equipment of ships withrestricted area of navigation, 3.6 are to be observed.

3.1.8 Manufacture of anchors and anchor chain cablesis to be in accordance with the Rules, Part 25 - Metallic mate-rials, 7.

3.2 EQUIPMENT NUMBER

3.2.1 The equipment of anchors and chain cables forall ships, except floating cranes and tugs, as given in tablesabove, is to be based on an Equipment Number En calculatedas follows:

En = ∆2/3 + 2B h + 0.1 A,where:

∆ = moulded displacement, in [t], to thesummer load waterline,

B = moulded breadth, in [m],h = effective height, in [m], from the

summer load waterline to the top ofthe uppermost house; for the lowesttier “h” is to be measured at centreline

from the upper deck or from a notionaldeck line where there is local disconti-nuity in the upper deck.

h = a + Σ hiwhere:

a = the distance from the summer loadwaterline amidships to the upper deck,in [m],

hi = height, in [m], on the centreline ofeach tier of houses having a breadthgreater than B/4.

A = area, in [m2], in profile view, of thehull, superstructures and houses abovethe summer load waterline which arewithin the Equipment length of thevessel and also have a breadth greaterthan B/4, see also 3.2.2.

3.2.2 When calculating h, sheer and trim are to be ig-nored, i.e. h is the sum of freeboard amidships plus the height(at centreline) of each tier of houses having a breadth greaterthan B/4.


2013

If a house having a breadth greater than B/4 isabove a house with a breadth of B/4 or less then the widehouse is to be included but the narrow house ignored.

Screens or bulwarks 1,5 m or more in height areto be regarded as parts of houses when determining h and A.The height of the hatch coamings and that of any deck cargo,such as containers, may be disregarded when determining hand A.

With regard to determining A, when a bulwark ismore than 1,5 m high, the area shown as A2 (see Fig. 3.2.2) isto be included in A.

The equipment length of the vessels is the lengthbetween perpendiculars but is not to be less than 96% norgreater than 97% of the extreme length on the summer water-line (measured from the forward end of the waterline).

The total length of chain given in Tables 3.1.2-1and 3.1.2-2 is to be divided in approximately equal parts be-tween the two bower anchors.

For dredgers of unrestricted service having nor-mal ship shape of underwater part of the hull the anchoringequipment is to be provided in accordance with these require-ments. When calculating the Equipment Number bucket lad-ders and gallows are not to be included. If however a dredgerhas unusual design of the underwater part of the hull, Registeris free to modify the requirements to anchoring equipment. Asfar as dredgers of limited service are concerned, the equipmentis to be provided at the discretion of the Register.

Figure 3.2.2

3.2.3 The equipment number En of a floating crane isto be determined by the following expression:

En = 1.5⋅∆2/3 + 2⋅B⋅h + 2⋅S + 0.1⋅A,

where ∆, B, h and A are to be calculated accord-ing to 3.2.1: in determining value A, the area of the upperstructure of the floating crane exposed to cross wind (duringnavigation) is to be calculated as the area bound by the con-struction contour of the floating crane.

S = the projection of the area, in [m2], exposedto wind (during navigation) on the crosssection of the midship, which extendsabove the upper edge of the uppermostdeckhouse included in the calculation of h;in this projection the area exposed to windis to be taken as the surface bound by theconstruction contour of the floating crane.

3.2.4 For tugs, the term 2,0⋅B⋅h expressed in formulafor equipment number En in 3.2.1 may be substituted by:

2,0 (a ⋅ B + Σ hi ⋅ bi)where:

a, B and hi are as defined in 3.2.1bi = breadth, in [m], of the widest superstruc-

ture or deckhouse of each tier having abreadth greater than B/4.

3.3 ANCHORS

3.3.1 General

Two of the rule bower anchors are to be con-nected to their chain cables and positioned on board ready foruse.

Where in column 4 of Table 3.1.2-1 three boweranchor are required the third anchor is intended as a sparebower anchor.

Installation of the spare bower anchor on boardis not compulsorily required. Register is free to permit otherarrangements at its discretion or not to require the spare an-chor as a condition of classification.

Ships with Equipment Numeral of 205 and lessmay have the second bower anchor as spare one on conditionthat provision is made for its quick getting ready for use.

Unmanned barges and pontoons where length isless than 30 m the anchor may be dispensed with and wherelength is greater than 30 m may have only one bower anchor.

3.3.2 Anchor mass

The mass, per anchor, of bower anchor given inthe Tables 3.1.2-1 and 3.1.2-2 is required for anchors of equalmass.

The mass of individual anchor may vary to 7%of the Table mass provided that the total mass of anchors isnot less than that required for anchors of equal mass.

When special type of anchors designated “highholding power anchor” of proven superior holding ability areused as bower anchors, the mass of each anchor may be 75%of the mass required for ordinary stockless bower anchors inthe Tables 3.1.2-1 and 3.1.2-2.

The mass of the stocked anchor, when used, andthat of stream anchor, excluding the stock, is to be 80% of themass required in the Tables 3.1.2-1 and 3.1.2-2 for stocklessbower anchors and the mass of the stock is to be 20%.

The mass of the heads of stockless anchor in-cluding pins and fittings are not to be less than 60% of the to-tal mass of the anchor.

3.3.3 High holding power anchors

3.3.3.1 For approval as a high holding power anchorsatisfactory tests are to be made on various type of bottom,and the anchor is to have a holding power at least twice that ofon ordinary stockless anchor of the same weight.

3.3.3.2 Full scale tests are to be carried out at sea onvarious types of bottom and to be applied to anchors theweights of which are, as far as possible, representative of thefull range of sizes proposed; for a definite group of the range


2013

the two anchors selected for testing (ordinary stockless an-chors and high holding power anchors) are to be of approxi-mately the same weight, and are to be tested in associationwith the size of chain cable appropriate to this weight.

3.3.3.3 The length of cable with each anchor is to besuch that the pull on the shank remains practically horizontal,for this purpose a scope of 10 is considered normal but a scopeof not less than 6 may be accepted. Scope is defined as the ra-tio of length of cable to depth of water.

3.3.3.4 Three tests are to be taken for each anchor andnature of bed. The pull is to be measured by dynamometer.The stability of the anchor and ease of breaking out are to benoted where possible. Tests are normally to be carried outfrom a tug but alternatively shore based tests may be accepted.Measurements of pull based on RPM/bollard pull curve of tugmay be accepted instead of dynamometer readings.

3.3.3.5 Tests in comparison with a previously approvedhigh holding power anchor may be accepted as a basis for ap-proval.

For approval and/or acceptance of high holdingpower anchors of the whole range of weight, tests are to becarried out on at least two - sizes of anchors and the weight ofthe maximum size to be approved could be accepted up to 10times the weight of large size tested.

3.3.3.6 The use of a super high holding power anchors(SHHP) is limited to restricted service vessels and subject tospecial consideration by the Register.

3.3.4 Manufacture

3.3.4.1 Anchors may be of forged, cast or welded con-struction.

3.3.4.2 Anchor parts are to be free from cracks, cavitiesand other defects affecting their strength. The external defectsmay be repaired by welding. Welding procedure is to beagreed with the Register.

3.3.4.3 The pins of the heads shaft and the pin of theshackle are to be efficiently locked against axial displacement.The locking may be effected by electric welding.

3.3.4.4 The manufacturer shall determine whether heattreatment of the anchor is to be needed after its manufacture,and if so, what type of heat treatment is to be used. If heattreatment is deemed necessary, it is to be carried out prior tothe proof testing of the anchor.

3.3.5 Testing

3.3.5.1 All cast or welded anchors or their parts are tobe tested by dropping on a steel plate not less than 100 mm inthickness. The height of dropping is given in Table 3.3.5.1-1.

Table 3.3.5.1-1

Anchor mass,[kg]

Height of dropping (measuredfrom plate up to lower edge of

anchor or its part), [m]below 750 4.5

from 750 to 1500 4.0from 1500 to 5000 3.5

over 5000 3.0

The heads of Hall's, Gruson's and high holdingpower anchors are dropped on the plate, the crown down-wards; the shanks of Hall's, Gruson's and high holding poweranchors and also the shanks with flukes of admiralty stockedanchor are dropped in horizontal position.

3.3.5.2 Moreover, each cast or welded shank and armsof the admiralty stocked anchor is to be suspended in a verticalposition, the flukes downwards, and dropped on two steelblocks put on the plate in such a manner that the distance be-tween them is half the span of the arms (Fig. 3.3.5.2.).

The thickness of the blocks is to be such as toprevent the anchor crown from striking against the plate.

Figure 3.3.5.2

3.3.5.3 After the drop test, the parts are to be suspendedand subjected to a hammer test with a hammer weighing notless than 3 kg. They must give out a clear ringing sound. If thesound is not clear, they are to be inspected by non-destructivemethods. If a part must be repaired, the testing procedure is tobe repeated.

3.3.5.4 Each cast anchor shackle is to be tested withoutthe anchor with non-statutory pin secured inside by a proof notless than:

F2 = 2F1,where:

F2 - proof load of the shackle, in [kN],F1 - proof load of the anchor, in [kN], accord-

ing to 3.3.5.9.In some cases this test may be applied selec-

tively to 5 per cent of the batch but to not less than twoshackles. A batch is considered to be composed of shacklesmanufactured from steel of the same grade and being heattreated either simultaneously or in the same conditions or bychecking the temperatures.

After testing under proof load, no fractures orpermanent deformations are to be detected.

3.3.5.5 Each anchor, irrespective of the method of itsmanufacture, is to be subjected to tensile test by application ofa proof load either on a special testing machine or by a loadsuspended to the flukes.

3.3.5.6 Hall and Gruson anchors and high holdingpower anchors are to be tested by simultaneous gripping ofboth arms (Fig. 3.3.5.6), first turned to one side and then to theother.


2013

Figure 3.3.5.6

3.3.5.7 The admiralty-stocked anchors are to be testedby applying the load to each fluke arm in succession (Fig.3.3.5.7). The test may be carried out both with or without thestock.

Figure 3.3.5.7

3.3.5.8 In all cases the proof load is applied on one sideto the statutory shackle and on the other side to the arms (forHall and Gruson anchors and high holding power anchors) oron an arm (for admiralty anchors) at a distance 1/3 of the armlength L away from the bill (see Figures 3.3.5.6 and 3.3.5.7).

3.3.5.9 The value of the proof load, which the anchorsof all sizes must withstand is not to be less than the load speci-fied in Table 3.3.5.9-1.

Proof load for intermediate values of the anchorweight is determined by linear interpolation.

3.3.5.10 For high holding power anchors the proof load istaken depending on the anchor mass increased by 33%.

3.3.5.11 Prior to the proof testing, a punch is to be madeon the anchor shank and also on each bill of flukes. ThenHall's, Gruson's and high holding power anchors are subjectedto a preliminary 2-minutes tension by a load equal to 0,5 F1.The load is then reduced down to 0,2 F1 and distance betweenthe punch marks is measured. After that the load is maintainedfor 2 minutes, then the load is reduced to 0,2 F1 and the dis-tance between the punch marks is measured again.

If the increase of the distance between the punchmarks exceeds 0,5 per cent of the initial distance, the anchor isto be rejected.

The admiralty stocked anchors are not subjectedto the preliminary tensions. The punch marks are to also befitted on them and then are subjected to proof load in durationof 2 minutes. No permanent deformations are allowed.

3.3.5.12 After Hall's, Gruson's and high holding poweranchors have been subjected to the proof load, the free rotationof their flukes through the complete angle is to be controlled.In case the rotation of flukes is impeded or they rotate throughon incomplete angle, the defects are to be removed and the testrepeated.

The results of repeated test are considered final.

3.3.5.13 Upon completion of proof load tests all anchorsare to be inspected to ascertain the possible cracks and defectsand then to be weighed.

Under special circumstances weight control ispermitted by checking at random only 5 percent for the totalnumber of anchors but not less than two anchors provided theapproved models are used.


2013

Table 3.3.5.9-1

Anchorweight

[kg]

Proofload[kN]

Anchorweight

[kg]

Proofload[kN]

Anchorweight

[kg]

Proofload[kN]

Anchorweight

[kg]

Proofload[kN]

50 23 1250 239 5000 661 12500 113055 25 1300 247 5100 669 13000 116060 27 1350 255 5200 667 13500 118065 29 1400 262 5300 685 14000 121070 31 1450 270 5400 691 14500 123075 32 1500 278 5500 699 15000 126080 34 1600 292 5600 706 15500 127090 36 1700 307 5700 713 16000 1300

100 39 1800 321 5800 721 16500 1330120 44 1900 335 5900 728 17000 1360140 49 2000 349 6000 735 17500 1390160 53 2100 362 6100 740 18000 1410180 57 2200 376 6200 747 18500 1440200 61 2300 388 6300 754 19000 1470225 66 2400 401 6400 760 19500 1490250 70 2500 414 6500 767 20000 1520275 75 2600 427 6600 773 21000 1570300 80 2700 438 6700 779 22000 1620325 84 2800 450 6800 786 23000 1670350 89 2900 462 6900 794 24000 1720375 93 3000 474 7000 804 25000 1770400 98 3100 484 7200 818 26000 1800425 103 3200 495 7400 832 27000 1850450 107 3300 506 7600 845 28000 1900475 112 3400 517 7800 861 29000 1940500 116 3500 528 8000 877 30000 1990550 125 3600 537 8200 892 31000 2030600 132 3700 547 8400 908 32000 2070650 140 3800 557 8600 922 34000 2160700 149 3900 567 8800 936 36000 2250750 158 4000 577 9000 949 38000 2330800 166 4100 586 9200 961 40000 2410850 175 4200 595 9400 975 42000 2490900 182 4300 604 9600 987 44000 2570950 191 4400 613 9800 998 46000 26501000 199 4500 622 10000 1010 48000 27301050 208 4600 631 10500 10401100 216 4700 638 11000 10701150 224 4800 645 11500 10901200 231 4900 653 12000 1110

3.4 CHAIN CABLES AND ROPESFOR BOWER ANCHORS

3.4.1 Ship with equipment number of 205 and less, inwhich the second bower anchor is permitted to be spare onemay be equipped with only one chain cable the length ofwhich is to be one half of that given in the equipment Table3.1.2-1 for two chains.

3.4.2 For the supply vessels the diameter of the chaincables is to be determined according to Table 3.1.2-1 two linesabove than required equipment number. The length of

chain cables of these ships is to be agreed with Register takingaccount specified depth and condition of anchorage.

The length of chain cables of unmanned bargesis to be two times length or 40 m, whichever is greater.

3.4.3 Chain cables of bower anchors are to be gradeddependent of their strength as specified in the Rules, Part 25 -Metallic materials, 7.2.

Grade 1 material used for chain cables CRS L1in conjunction with high holding power anchors must have atensile strength of not less than 400 N/mm2.

3.4.4 For ships with equipment number of 90 and less,in alternative to stud link chain cables, short link chain cables


2013

may be considered, for acceptance, by the Register on the ba-sis of their design, strength and steel quality.

3.4.5 In alternative to the stud link or short link cableswire ropes may be used for:

- both the bower anchors of ships bellow 30m in length

- one of two bower anchors of ships be-tween 30 m and 40 m in length

The wire ropes, above mentioned, are to havestrength equal to that of tabular chain cable of grade 1 andlength equal 1.5 times the corresponding tabular length ofchain cables.

Wire ropes of trawl winches on fishing vesselscomplying with these requirements may be used as anchorchain cables.

3.4.6 The chain cables are to be composed of separatechain length, except for the chains less than 15 mm in diame-ter, which need not be divided into chain lengths.

The lengths of chains are to be interconnectedwith joining links. The use of joining shackles instead ofjoining links is to be specially considered by Register.

Depending on their location in the chain cablethe lengths are divided into:

- anchor part fastened to the anchor (forerun-ner),

- intermediate lengths,- inboard part, secured to the chain cable re-

leasing device.

3.4.7 To be considered a separate length, the anchorpart must be provided with a swivel, end link, and an adequatenumber of common and enlarged links. If the dimensions ofthe relevant part of the cable chain are sufficient to form alength, the anchor length may consist of a swivel, end link andjoining link only.

On cable chains divided into lengths a swivelmust be attached as close as possible to the anchor. The swivelpins shall point toward the middle of the chain cable. Thechain length is to be connected to the anchor by means of anend shackle with pin.

3.4.8 The intermediate length is to be no shorter than25 m and no longer than 27,5 m, and it is to have an odd num-ber of links. The totals for the length of two chains given inthe equipment table include only the sums of the middlelengths, without anchor and inboard lengths. If there are anodd number of intermediate lengths, then the chain cable onthe right side is to have one length more than the chain cableon the left side.

3.4.9 The inboard end length of each chain shall con-sist of a special link of enlarged size which, however, shallpass freely through the wildcat of the anchor machinery se-cured to the chain cable releasing device, and of a minimumnumber of common and enlarged links which are necessary toconstitute and independent chain length. The inboard endchain length may consist of one end link only, provided therelation between the dimensions of the chain cable parts andthe chain cable-releasing device allows of such arrangement.

In all other respects the chain cables for boweranchors shall comply with the requirements of the Rules, Part25 - Metallic materials, 7.

The end of each wire rope is to be spliced into athimble, clamp or socket and in order to increase the anchorholding power and the damping of jerk loads, the end of eachwire rope is to be connected to the anchor by means of a chaincable section of at least 12.5 meters in length and having thesame strength as the wire rope. The chain cable section is to besecured to the wire rope fitting and the anchor shackle bymeans of joining shackles being equal to the wire ropes instrength.

The length of the chain cable section may be in-cluded into 1,5 times the length of wire ropes specified in theprevious paragraph.

3.4.10 The wire ropes anchors are to have at least 114wires and not less than one natural fibre core. The wires of theropes are to have at least thin zinc coating in accordance withapplicable standards.

In all other respects, the wire ropes for anchorsshall meet the requirement of the Rules, Part 25 - Metallicmaterials, 7.

3.4.11 Stream anchors may use the chain cables withstud or without them as well as wire ropes, which shall meetthe requirements of 3.4.8 and 3.4.9.

3.5 ANCHOR APPLIANCES

3.5.1 Stoppers

3.5.1.1 Each bower anchor chain cable or rope is to beprovided with stopper holding the anchor in the hawse pipewhen stowed for sea or, in addition, intended for holding theship at anchor.

In ships having no anchor machinery or havingthe anchor machinery, which is not in compliance with theRules, Part 9 - Machines, 6.3 stoppers must be installed forholding the ship at anchor.

3.5.1.2 Where the stopper is intended only for securingthe anchor in the hawse pipe, its parts are to be calculated towithstand the chain cable strain to twice the weight of the an-chor, the stresses in the stopper parts not exceeding 0,4 timesthe yield point of their material.

Where the stopper comprises a chain cable orrope, this is to have safety factor 5 in relation to the breakingload of the chain cable or actual breaking strength of the ropeunder the action of a force equal to twice the weight of the an-chor.

3.5.1.3 Where the stopper is intended for riding the shipat anchor, its parts are to be calculated on assumption that thestopper is to be subjected to a force in the chain cable equal to0,8 times its breaking load. The stresses in the stopper partsare to not exceed 0,95 times the yield point of their material.Where the stopper comprises a chain cable or rope, they are tobe of strength equal to that of the chain cable for which theyare intended.

3.5.2 Device for securing and releasing theinboard end of the chain cables

3.5.2.1 The inboard ends of the chain cables are to besecured to the structures by fastening able to withstand a force


2013

not less than 15% nor more than 30% of the breaking load ofthe chain cable.

3.5.2.2 The fastening is to be provided with means suit-able to permit, in case of emergency, an easy slipping of thechain cables to sea, operable from an accessible position out-side the chain locker.

3.5.3 Laying of chain cables

3.5.3.1 Laying of chain cables shall provide for their runwhen dropping or hoisting the anchors.

3.5.3.2 The anchor shank shall easily enter the hawsepipe under the mere action of the chain cable tension and shallreadily take off the hawse pipe when the chain cable is re-leased.

3.5.3.3 It is recommended that thickness of the hawsepipe is not to be less than 0.4 times the diameter of chain cablepassing through the hawse pipe.

3.5.4 Chain lockers

3.5.4.1 For stowage of each bower anchor chain lockersare to be provided.

When one chain locker is designed for twochains, it is to be provided with an internal division so thatseparate stowage of each chain is ensured.

3.5.4.2 The chain locker is to be of capacity and depthadequate to provide an easy direct lead of the cables throughthe chain pipes and self-stowing of the cables.

The minimum required stowage capacity with-out mud box for the two bow anchor chains is as follows:

1000001,1 2 ldS = , [m3]

where:d = chain diameter, [mm], according to Ta-

bles 3.1.2-1 and 3.1.2-2l = total length of stud link chain cable ac-

cording to Tables 3.1.2-1 and 3.1.2-2The total stowage capacity is to be distributed on

two chain lockers of equal size for the port and starboard chaincables. The shape of the base areas is to as far as possible bequadratic with a maximum edge length of 33⋅d. As an alterna-tive, circular base areas may be selected, the diameter ofwhich is not to exceed 30 –35⋅d.

Above the stowage of each chain locker in addi-tion a free depth of h = 1500 mm is to be provided.

3.5.4.3 The chain locker design and covers of the accessopenings are to be watertight as necessary to prevent acciden-tal flooding of the chain locker which could damage essentialauxiliaries or equipment (located outside the chain locker) orcould affect the proper operation of the ship.

3.5.4.4 The drainage facilities for chain locker shallmeet the requirements of the Rules, Part 8 - Piping, 2.11, andthe lighting with the requirements of Part 12 - Electricalequipment, 6.7.

3.5.4.5 Closure of chain lockers

3.5.4.5.1 This requirement is applicable to ships with alength of 24 m and above built in accordance with the 1966Load Line Convention or the 1988 Protocol to the Load LineConvention and the keels of which are laid or which are at asimilar stage of construction on or after 1 July 2003.

3.5.4.5.2 Spurling pipes and cable lockers are to bewatertight up to the weather deck. Bulkheads between separatecable lockers (see Fig. 3.5.4.5.2-1), or which form a commonboundary of cable lockers (see Fig. 3.5.4.5.2-2), need nothowever be watertight.

Figure 3.5.4.5.2-1 Figure 3.5.4.5.2-2

3.5.4.5.3 Where means of access is provided, it is to beclosed by a substantial cover and secured by closely spacedbolts.

3.5.4.5.4 Where a means of access to spurling pipes orcable lockers is located below the weather deck, the accesscover and its securing arrangements are to be in accordancewith recognized standards* or equivalent for watertight man-hole covers. Butterfly nuts and/or hinged bolts are prohibitedas the securing mechanism for the access cover.

3.5.4.5.5 Spurling pipes through which anchor cables areled are to be provided with permanently attached closing ap-pliances** to minimize water ingress.

* Examples of the recognized standards are such as:i) ISO 5894-1999ii) China: GB 11628-1989 Ship Manhole Co-

veriii) India: IS 15876-2009 "Ships and Marine

Technology manholes with bolted covers"iv) Japan: JIS F2304, "Ship's Manholes" and

JIS F2329, "Marine Small Size Manhole"v) Korea: KSV 2339:2006 and KS VISO5894vi) Norway: NS 6260:1985 to NS 6266:1985vii) Russia: GOST 2021-90 "Ship's steel man-

holes. Specifications"** Examples of acceptable arrangements are such as:

i) steel plates with cutouts to accomodatechain links or

ii) canvas hoods with a lashing arrangementthat maintains the cover in the secured po-sition.

3.5.5 Anchor machinery

3.5.5.1 An anchor windlass must be provided if the an-chor mass exceeds 35 kg.

3.5.5.2 On ships with an equipment number of 205 orless, a hand-operated anchor windlass may be installed, orother deck machinery may be used to release or hoist the an-chor.


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3.5.5.3 Construction and power requirements for the an-chor windlass are given in the Rules, Part 9 - Machines, 6.3.

Strength requirements for the windlass founda-tions are given in Section 7.14.

3.5.5.4 Unless located at least 2.4 m above the cargodeck the windlass and the openings of chain pipes leading intothe chain locker are to be fitted at distance of not less than 3 mfrom cargo tank boundaries, if liquids having a flashpoint notexceeding 60oC are intended to be carried.

3.5.5.5 On ships intended to carry in bulk flammableliquids having the flash point bellow 60oC no deck machineryis to be fitted directly on the decks being the top of cargo tanksand bunkers.

In this case, the deck machinery is to be fitted onspecial foundations, the construction of which provides forfree circulation of air underneath the machinery.

3.5.6 Spare parts

3.5.6.1 Every ship whose anchor arrangement includes aspare bower anchor and cable chains must have three sparejoining links and one end shackle of the corresponding dimen-sions. If the ship has no spare bower anchor the shackle is notmandatory.

3.5.6.2 Every ship whose anchor arrangement includes aspare anchor and cable chains must have all the parts neededfor connecting the wire rope to the anchor shackle.

3.5.7 Permissible weardown of chain cables

3.5.7.1 When the mean diameter of link, at its mostworn part, is reduced by 12% or more from its required nomi-nal diameter it is to be renewed.

3.5.7.2 The mean diameter is half value of the sum ofthe minimum diameter found in one cross-section of the linkand of the diameter measured in perpendicular direction in thesame cross-section.

3.6 EQUIPMENT FOR SHIPS INRESTRICTED AREA OF NAVIGATION

3.6.1 All vessels, except fishing vessels

3.6.1.1 Provisions for equipment for vessels with re-stricted service, except fishing vessels, are based on equip-ment number in accordance with 3.2 and given in Table3.6.1.1-1.

Table 3.6.1.1-1

Sailing area Requirements for equipment

2 No reduction

3,4 According equipment number reducedby 15%

5, 6 According equipment number reducedby 25% taking in to account 3.6.1.2

7, 8 According to 3.6.1.3

3.6.1.2 Ship mentioned in 3.6.1.1 with equipment num-ber 35 and less and of restricted navigation area 6, if they arenot passenger ships may have only one bower anchor and onechain cable the length of which is two times less than that re-quired in Table 3.1.2-1.

3.6.1.3 Provisions for equipment of ships of restrictednavigation area 7 and 8 are to be determined according to Ta-ble 3.1.2-1. The anchor weight may be reduced up to 40% andchain diameter may be determined according to the reducedanchor mass.

If an anchor mass of less than 80 kg has beendetermined, only one anchor is required and half length ofchain cable required by Table 3.1.2-1.

3.6.1.4 For ships of restricted area of navigation 5, 6, 7and 8 stream anchor is not required.

3.6.2 Fishing vessels of restricted navigation area 3,4 and 5

3.6.2.1 Provisions for equipment of ships with length 20< L ≤ 40, are to be determined according to Table 3.6.2.1-1based on equipment number obtained as follows:

Enf = L (B + D) + Σ0.5 ⋅ l ⋅ h,

where:l = length of individual superstructure and

deckhouse, m;h = height of individual superstructure and

deckhouse at centreline, m.Deckhouse having a breadth of less than B/4

may be ignored.For vessels having a length of 20 m and less the

equipment is to be determined for the length L in accordancewith Table 3.6.2.1-1.

3.6.2.2 Provisions stated in 3.3, 3.4 and 3.5 are to alsobe observed.

3.6.2.3 The second anchor is considered as spare one oncondition that provision is made for its quick getting ready foruse.

3.6.2.4 For ships with length less than 20 m the weightof spare anchor may be 70% of the value required by Table3.6.2.1-1.

3.6.2.5 Stream anchor is not required

3.6.3 Fishing vessels of restricted navigation area 6,7 and 8

3.6.3.1 Fishing vessels of this sailing area, with lengthless than 16 m may have only one anchor and chain cable withlength two times less than in Table 3.6.2.1-1.


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Table 3.6.2.1-1

Bower anchors Stud link chain cables Mooring ropes

Diameter Diameter

Length

L[m]

Equipmentnumber

EnfNo. Weight per

anchors[kg]

Totallength

[m]d1

[mm]d2

[mm]

Totallength

[m]d3

[mm]d4

[mm]

to 14 - 2 60 95 11.0 - 80 - 20

14-16 - 2 75 105 11.0 90 10 20

16-18 - 2 85 110 11.0 100 10 20

18-20 - 2 95 110 12.5 12.5 120 10 20

to 270 2 110 137.5 12.5 12.5 150 10 22

270-300 2 140 165 14.0 12.5 180 10 22

300-330 2 180 165 14.0 12.5 200 10 22

330-360 2 210 220 16.0 14.0 225 10 24

360-400 2 250 220 16.0 14.0 225 10 24

400-450 2 300 247.5 17.5 16.0 225 10 24

450-500 2 370 247.5 19.0 17.5 250 12 26

L = 20 - 40

over 500 2 440 275.0 22.0 19.0 250 12 26

Remarks:- Short link cable of same proof load may be taken in lieu of stud link chain cables for ships with Enf less than 330.

Explanatory notes:d1 .... Chain diameter grade CRS-L1d2 .... Chain diameter grade CRS-L2d3 .... Diameter of wire rope 6 x 24, breaking strength 1570 N/mm2.d4 .... Diameter of polyamide ropes and manila ropes.


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4 MOORING ARRANGEMENT


4.1.1 The number, length and breaking strength ofmooring ropes are to be determined for all ships with the ex-ception of fishing vessels according to Table 3.1.2-1 and forfishing vessels according to Table 3.1.2-2, and Table 3.6.2.1-1. The breaking loads specified in tables are valid for wireropes and ropes of natural fibre (manila) only.

4.1.2 For ships with a ratio A/En exceeding 0,9, an in-creased number of mooring ropes compared to those specifiedin Table 3.1.2-1 must be provided as follows:

1 rope -when

0,9 < 11,EA

n≤ ,

2 ropes - when

1,1 < 21,EA

n≤ ,

3 ropes-when

nEA

> 1,2,

where:En and A - equipment number and area exposed to wind

according to 3.2.

4.1.3 On ships with individual mooring ropes having abreaking strength exceeding 490 kN according to Table 3.1.2-1, the following ropes may be used:

- with reduced breaking strength and an in-creased number of ropes,or

- with increased breaking strength and a re-duced number of ropes.

In such cases the total breaking strength of allthe mooring ropes is not to be less than the total rope strengthforeseen according to Table 3.1.2-1. The number of ropes is tonot be less than 6, and the breaking strength of a single rope isnot to be lower than 490 kN.

4.1.4 The length of the individual mooring ropes maybe up to 7% less than that given in the Table 3.1.2-1 providedthat the total length of all wires and ropes is not less than thesum of the individual lengths.

4.1.5 If synthetic-fibre ropes are used, the breakingstrength of a rope Fc is not to be less than:

Fc = 0,0742⋅δm⋅Ft8/9 , [kN]

where:δm = the mean relative elongation to the break-

ing point of a synthetic rope, in percent-ages but not less than 30%,

Ft = actual breaking strength of a mooring rope,given in Table 3.1.2-1 or 3.1.2-2, in [kN].

4.1.6 Provisions for mooring ropes of non-propelledunmanned barges are as follow:

L < 65 m : 2 ropesL ≥ 65 m : 3 ropes

Length of the mooring ropes is to be two timesof length or 80 m, whichever is greater.

4.2 MOORING ROPES

4.2.1 Mooring ropes may be made of steel wire, or ofnatural or synthetic fibres except on ships carrying in bulkflammable liquids with a flash point under 60o.

Operations with steel wire ropes are allowedonly on those superstructure decks which are not the top of thecargo tanks and which have no cargo pipelines led over them.

Regardless of the breaking strength as specifiedin Tables 3.1.2-1, 3.1.2-2 or 3.6.2.1-1, fibre ropes with a di-ameter less than 20 mm are not acceptable.

4.2.2 Wire ropes are to be of a flexible constructioncomposed according to Table 4.2.2

Table 4.2.2-1

Breaking load (BL)[kN] Composition

BL ≤ 216 72 wires in 6 strands with 7fibre cores

216 < BL ≤ 490 144 wires in 6 strands with 7fibre cores

BL > 490 216 wires in 6 strands with 1fibre core

4.2.3 Wire ropes for use in association with mooringwinches where the rope is to be stored on the drum may beconstructed with on independent wire rope core instead of fi-bre core. The number of wires in such ropes is not to be lessthan 216.

In all other respects these ropes shall meet therequirements of the Rules, Part 25 - Metallic materials, 8.

4.2.4 Natural fibre ropes are to be either manila or si-sal. The ships having equipment number 205 and less are per-mitted to use hemp ropes. The use of hemp ropes in ships withequipment number over 205 is subject to special considerationin each particular case.

In all other respects these ropes shall meet therequirements of the Rules, Part 25 - Metallic materials, 2.

4.2.5 The synthetic fibre ropes may contain capron,nylon, polypropylene and other approved synthetic materialsas well as combinations of fibres of different approved materi-als.

In all other respects, the ropes of synthetic fibrematerial shall meet the requirements of the Rules, Part 24 -Non-metallic materials, 2.

4.3 MOORING APPLIANCES

4.3.1 The number and position of mooring bollards,fairleads and other mooring appliances depend on the con-struction particulars, purpose and general arrangement of theship.


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4.3.2 Bollards may be of steel or cast iron. Small shipsequipped only with natural fibre or synthetic fibre ropes arepermitted to use the bollards made of light alloys. As to themethod of manufacture, the bollards may be welded or cast.

4.3.3 The outside diameter of the bollard column is tobe not less than 10 times the diameter of the steel rope and 5,5times the diameter of the synthetic-fibre rope; nor is to be lessthan one circumference of the fibre rope to be used with thebollard. The distance between the axis of the bollard column isnot to be less than 25 times the diameter of the steel rope, or 3circumferences of the fibre rope are to be used with the bol-lard.

4.3.4 Bollards, fairleads and other parts of mooringappliances, with the exception of rope stoppers, are to be sodesigned that the stresses in their parts do not exceed 0,95times the yield point of the material.

The breaking strength of a rope stopper is to benot less than 0,15 of the breaking strength of the whole ropefor which it is intended.

4.3.5 For the requirements applicable to design andconstruction of shipboard fittings and supporting structuresused for the mooring operations, see 5.6.

4.4 MOORING MACHINERY

4.4.1 Specially fitted appliances, such as drums, cap-stans etc. may be provided for winding up mooring ropes, andas well other existing deck arrangements such as anchorwindlass, cargo winches etc. provided with drums for ropecoiling.

4.4.2 Decisions as to the number and type of mooringmachinery are to the owner and designer's discretion, on con-dition that the rated forced of the machinery does not exceed1/3 of the breaking strength of the mooring ropes to be usedon the ship and that the requirements of the Rules, Part 9 -Machines, 6.4 are satisfied.


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5 TOWING ARRANGEMENT


5.1.1 Each ship is to be provided with towing ar-rangement, which meets the requirements of 5.2, 5.3 and 5.6.

5.1.2 All oil tankers over 20000 tons deadweight, in-cluding combination carriers, chemical tankers and liquefiedgas carriers shall comply with requirements of 5.4.

5.1.3 Tugs shall comply with requirements of 5.5.

5.2 TOWING LINE

5.2.1 Lengths and breaking loads of a towing linesspecified in the Table 3.1.2-1 are recommendations only.

5.2.2 For shipborn barges the breaking strength of thetowing line is determined by the formula:

Fp = 16⋅n⋅B⋅d, in [kN],where:

n = number of barges towed,B = width of barges, in [m],d = draught of the barges, in [m].The breaking strength of the rope is used in cal-

culations of equipment strength for shipborn barges. The linesfor towing barges may be stored on the barges if theshipowner so desires, or they may be kept on tugboats and notbe included as part of the barge equipment.

5.2.3 Towing lines may be made of steel wire or ofnatural or synthetic fibres. The requirements for mooring ropeas provided in 4.2 are also applicable to towing lines.

5.3 TOWING APPLIANCES

5.3.1 The number and location of towing bollards andchocks depend on the construction particulars, purpose andgeneral arrangement of the ship.

5.3.2 The requirements for mooring bollards andchocks as provided in 4.3.2, 4.3.3 and 4.3.4 are also applicableto towing bollards and chocks.

5.4 EMERGENCY TOWINGARRANGEMENTS ON TANKERS

5.4.1 General requirements

5.4.1.1 Emergency towing arrangements shall be fittedat both ends on board every tanker listed in 5.1.2.

5.4.1.2 For tankers constructed on or after 1 July 2002:.1 the arrangements shall, at all times, be ca-

pable of rapid deployment in the absenceof main power on the ship to be towed andeasy connection to the towing ship. Atleast one of the emergency towing ar-rangements shall be pre-rigged ready forrapid deployment; and

.2 emergency towing arrangements at bothends shall be of adequate strength takinginto account the size and deadweight of theship, and the expected forces during badweather conditions. The design and con-struction and prototype testing of emer-gency towing arrangements shall be ap-proved by the Administration, based on theGuidelines developed by the Organiza-tion*.

Figure 5.4.1.2Typical emergency towing arrangement

5.4.1.3 For tankers constructed before 1 July 2002, thedesign and construction of emergency towing arrangementsshall be approved by the Administration, based on the Guide-lines developed by the Organization*.

* Refer to the Guidelines on emergency towing arrangementsfor tankers, adopted by the Maritime Safety Committee byresolution MSC.35(63), as amended.


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5.4.1.4 Towing arrangements may be (1) a packagedself contained unit, or (2) a unit comprised of individuallytested components assembled onboard the vessel. Both ar-rangements should meet the specified strength requirementsand undergo a deployment test on board the vessel as requiredby MSC. 35 (36). See also IACS UI SC 113.

Fixed gear such as strongpoints, fairleads, foun-dations and associated vessel supporting structure are to bedemonstrated as adequate for the loads specified in 5.4.2.2 bymeans of analysis or calculations submitted to the Register. Ifsuch analysis is deemed not appropriate depending on struc-tural configuration, proof test may be required.

Articles of loose gear such as chains, towingpennants and associated end fittings, and shackles or otherconnecting links are to be tested to the requirements of theRules, Part 25 - Metallic materials, 2.

5.4.1.5 Where a manufacturer requests a certificate oftype approval for a complete packaged towing arrangement,one assembled unit to undergo prototype test to 2 x SWL (safeworking load).

5.4.1.6 Existing emergency towing arrangements fittedin accordance with Resolution A.535(13) and approved by theRegister may retain at forward location.

Table 5.4.2.1-1Towing components

Forward of ship Aft of ship Strength requirements

Pick-up gear Optional Yes '

Towing pennant Optional Yes Yes

Chafing gear Yes Depending on design Yes

Fairlead Yes Yes Yes

Strongpoint Yes Yes Yes

Roller pedestal Yes Depending on design -

5.4.2 Towing components, strength andtechnical characteristics

5.4.2.1 The towing arrangements generally shall consistof the major components specified in Table 5.4.2.1-1.

5.4.2.2 Towing components as specified in 5.4.2.1 forstrength are to be designed with a working strength of at least1000 kN for tankers of 20000 tonnes deadweight and over butless than 50000 tonnes deadweight, and at least 2000 kN fortankers of 50000 tonnes deadweight and over (workingstrength is defined as one half ultimate strength). The strengthis to be sufficient for all relevant angels of towing line, i.e. upto 90o from the ship's centreline to port and starboard and 30o

vertical downwards.Other components are to be designed with a

working strength sufficient to withstand the load to whichsuch components may be subjected during the towing opera-tion.

5.4.2.3 Length of the towing pennant is to be at leasttwice the lightest seagoing ballast freeboard at the fairleadplus 50 m.

5.4.2.4 The bow and stern strongpoint and fairleads areto be located so as to facilitate towing from either side of thebow and stern and minimise the stress on the towing system.

5.4.2.5 Fairleads opening are to be large enough to passthe largest portion of the chafing gear, towing pennant ortowing line.

The fairlead has to give adequate support for thetowing pennant during towing operation, which means bend-ing 90o to port, and to starboard side and 30o vertical down-wards. The bending ratio (towing pennant bearing surface di-ameter to towing pennant diameter) is not to be less than 7 : 1.

5.4.2.6 If a chafing chain is to be used on design ofchafing gear, the following characteristics are to be provided:

.1 The chafing chain is to be stud link chain.

.2 The chafing chain is to be long enough toensure that the towing pennant remainsoutside the fairlead during the towing op-eration. A chain extending from the strongpoint to a point at least 3 m beyond thefairlead should meet this criterion.

.3 One end of the chafing chain is to be suit-able for connection to the strongpoint. Theother end is to be fitted with a standardpear-shaped open link (see Fig. 5.4.2.6)allowing connection to a standard bowshackle.

.4 The chafing chain is to be stowed in such away that it can be rapidly connected to thestrongpoint.

Figure 5.4.2.6Standardised pear-shaped link

619 mm

330 mm

91 mm

74 mm 61 mm


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5.4.2.7 A termination of the towing pennant is to be ahard eye-formed allowing connection to a standard bowshackle.

5.4.2.8 To ensure ready availability and rapid deploy-ment, emergency towing arrangements shall comply with thefollowing criteria:

.1 The aft emergency towing arrangements are tobe pre-rigged and be capable of being deployedin a controlled manner in harbour conditions notmore than 15 min.

.2 The pick-up gear for the aft towing pennant is tobe designed at least for manual operation by oneperson taking into account the absence of powerand the potential for adverse environmental con-ditions that may prevail during such emergencytowing operations. The pick-up gear is to beprotected against the weather and other adverseconditions that may prevail.

.3 The forward emergency towing arrangement isto be capable of being deployed in harbour con-ditions in not more than 60 min.

.4 The forward emergency towing arrangements isto be designed at last with a means of securing atowing line to the chafing gear using a suitablypositioned pedestal roller to facilitate connectionof the towing pennant.

.5 Forward emergency towing arrangements whichcomply with the requirements for aft emergencytowing arrangements may be accepted.

.6 All emergency towing arrangements are to beclearly marked to facilitate safe and effective useeven in darkness and poor visibility.

5.4.2.9 All emergency towing components are to be in-spected by ship personnel at regular intervals and maintainedin good working order.

5.5 SPECIAL ARRANGEMENTFOR TUGS

5.5.1 Towing hook or equivalent is normally to be lo-cated 5 to 10% of the ship's length abaft amidships, but in nocircumstances is to be sited forward of the longitudinal centreof gravity of the tug in any anticipated condition of loading.

5.5.2 Towing hooks should have reliable slip ar-rangement which facilitate towing line release regardless ofangle of heel and of direction of towing line.

The releasing device is to be operable from thebridge as well as in the vicinity of hook itself.

Where the ship is fitted with a spare towinghook, in addition to the main one, this hook need not be slip-type and have a device for releasing the towing line.

5.5.3 The number and type of equipment and outfitforming special arrangement for tugs which ensures towingoperations under different service conditions are determinedby the shipowner considering that such equipment and outfitshall satisfy the requirements of the present chapter.

5.5.4 The main determining factor in providing thetugs with a special arrangement is the rated towing pull (F).The numerical value of F is within the owner's and designer's

discretion, and all calculations pertaining to the determinationof this value are not subject to approval by the Register.

If, however, during mooring and sea trials of thetug, the towing force is found to exceed the value F, Registermay require strengthening of the towing arrangements units ora restriction of power during towing operations.

The bollard pull of the vessel is to be obtainedby a special test procedure approved by Register. The resultsof test are to be shown in diagram bollard pull/time (see Fig.5.5.4.).

Figure 5.5.4

5.5.5 The actual breaking strength of the towing line isnot to be less than 3F and maximum bollard pull is not to begreater than 50% of breaking strength of towing line.

The requirements of 4.2 for mooring ropes arealso applicable to the towing line.

The length of towing line for towing operationsis to be at least 150 m.

5.5.6 All stressed parts of the towing arrangement(such as the towing hook, towing rails, etc.) as well as thefastenings for securing these parts to the ship's hull are to bedesigned to take the actual breaking load of the towing line.The stresses in these parts are not to exceed 0,95 times the up-per yield stress of their material.

5.5.7 Each towing hook is to be provided with shockabsorbers whose ultimate damping load is not to be less than1,3 times the towing force. The towing hooks, for tugs of lessthan 220 kW, of restricted navigation area 6,7 and 8, may haveno shock absorbers.

5.5.8 The device for protection of the hook fromoverloading must be adjusted to a breaking strength threetimes the nominal towing force.

5.5.9 Prior to installation on board the ship the towinghooks are to be tested by application of a proof load equal totwice the towing force.

5.5.10 The towing beams are to be made of pipes orother suitable sections. Wide and high beams are to be sup-ported by (Λ) type tubular struts, which are to be arranged inthe centreline of the ship or symmetrically in relation to it. Onthe bulwark, the beams are to be connected with bracketswhose free edges are to be framed with a bar section or pipe.


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5.5.11 The section modulus of the towing beam is notto be less than:

W = 0,343 ⋅ 10-2 eHRLld 2

, [cm3],

where:d = diameter of the towing line, in [mm],L = the length of the towing line, in [m], not

to be less than 300 m,l = distance between the struts or between

one strut and the bulwark, in [m],ReH = yield point of the beam material, in

[N/mm2].

5.5.12 The cross-sectional area of each branch of aΛ-shaped strut is not to be less than:

eHRLd,f

2030= , [cm2] ,

where:ReH = yield point of the strut material, in

[N/mm2].

5.5.13 The wire stopper and its fastenings are to besuch that their breaking load is not less than 1,5 times thetowing force.

5.5.14 The requirements for the design of towingwinches are specified in the Rules, Part 9 - Machines, 6.5.

5.5.15 The length of towing line on winch is not to beless than 400 m.

5.6 SHIPBOARD FITTINGS ANDSUPPORTING HULL STRUCTURESASSOCIATED WITH TOWING AND

MOORING

5.6.1 Application and definitions

This requirement is to apply to design and con-struction of shipboard fittings and supporting structures usedfor the normal towing and mooring operations. For the emer-gency towing arrangements, ships subject to SOLAS regula-tion II-1/3-4 are to comply with that regulation and resolutionMSC.35(63) as may be amended.

For the requirements of SOLAS regulation II-1/3-8 relating to towing and mooring equipment, see IACSunified interpretation SC 212.

The net minimum scantlings of the supportinghull structure are to comply with the requirements given in5.6.2.5 and 5.6.3.5. The net thicknesses, tnet, are the memberthicknesses necessary to obtain the above required minimumnet scantlings. The required gross thicknesses are obtained byadding the total corrosion additions, tk, given in 5.6.5, to tnet.

For the purpose of this requirement:- Conventional vessels means new dis-

placement-type vessels of 500 GT andabove, excluding high speed craft, specialpurpose vessels, and offshore units of alltypes.

- Shipboard fittings means those compo-nents limited to the following: bollards and

bitts, fairleads, stand rollers, chocks usedfor the normal mooring of the vessel andthe similar components used for the nor-mal towing of the vessel. Other compo-nents such as capstans, winches, etc. arenot covered by the requirements of thisSection. Any weld or bolt or equivalentdevice connecting the shipboard fitting tothe supporting structure is part of the ship-board fitting and subject to the Industrystandard applicable to this shipboard fit-ting.

- Supporting hull structures means thatpart of the ship structure on/in which theshipboard fitting is placed and which is di-rectly submitted to the forces exerted onthe shipboard fitting. The supporting hullstructure of capstans, winches, etc. usedfor the normal towing and mooring opera-tions mentioned above is also subject tothe requirements of this Section.

- Industry standard means internationalstandard (ISO, etc.) or standards issued bynational association which are recognisedin the country where the ship is built.

5.6.2 Towing

5.6.2.1 Strength

The strength of shipboard fittings used for nor-mal towing operations at bow, sides and stern and their sup-porting hull structures are to comply with the requirements ofthis Section.

5.6.2.2 Arrangement

Shipboard fittings for towing are to be locatedon longitudinals, beams and/or girders, which are part of thedeck construction so as to facilitate efficient distribution of thetowing load.

Other arrangements may be accepted (for Pan-ama chocks, etc.) provided the strength is confirmed adequatefor the intended service.

5.6.2.3 Load considerations

Unless greater safe working load (SWL) ofshipboard fittings is specified by the applicant, the minimumdesign load to be used is the following value of (1) or (2),whichever is applicable:

(1) for normal towing operations (e.g. har-bour/manoeuvring), 1.25 times the in-tended maximum towing load (e.g. staticbollard pull) as indicated on the towingand mooring arrangements plan.

(2) for other towing service (e.g. escort), thenominal breaking strength of the towingline according to Tables 3.1.2-1 and 3.1.2-2 for the ship’s corresponding En is to beapplied. (see Note)

NOTE: Side projected area including maximum stacks of deckcargoes is to be taken into account for selection of towing lines


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The design load is to be applied through thetowing line according to the arrangement shown on the towingand mooring arrangements plan.

When a specific SWL is applied for a shipboardfitting at the request of the applicant, by which the design loadis to be greater than the above minimum values, the strengthof the fitting is to be designed using this specific design load.

The method of application of the design load tothe fittings and supporting hull structures is to be taken intoaccount such that the total load need not be more than twicethe design load, i.e. no more than one turn of one line (see Fig.5.6.2.3).

Figure 5.6.2.3

5.6.2.4 Shipboard fittings

The selection of shipboard fittings is to be madeby the shipyard in accordance with an Industry standard (e.g.ISO3913 Shipbuilding welded steel bollards) accepted by theRegister.

When the shipboard fitting is not selected froman accepted Industry standard, the design load used to assessits strength and its attachment to the ship is to be in accor-dance with 5.6.2.3.

5.6.2.5 Supporting hull structure

5.6.2.5.1 Arrangement

The reinforced members (carling) beneath ship-board fittings are to be effectively arranged for any variationof direction (horizontally and vertically) of the towing forces(which is to be not less than the design load as per 5.6.2.3)acting through the arrangement of connection to the shipboardfittings.

5.6.2.5.2 Acting point of towing force

The acting point of the towing force on ship-board fittings is to be taken at the attachment point of a towingline or at a change in its direction.

5.6.2.5.3 Allowable stresses

Allowable stresses under the design load condi-tions as specified in 5.6.2.3 are as follows:Normal stress: 100% of the specified minimum yield point ofthe material;Shearing stress: 60% of the specified minimum yield point ofthe material;

No stress concentration factors being taken intoaccount.

Normal stress is the sum of bending stress andaxial stress with the corresponding shearing stress acting per-pendicular to the normal stress.

5.6.2.6 Safe working load (SWL)

5.6.2.6.1 The SWL used for normal towing operations(e.g. harbour/manoeuvring) is not to exceed 80% of the designload per 5.6.2.3 (1) and the SWL used for other towing opera-tions (e.g. escort) is not to exceed the design load per 5.6.2.3(2). For fittings used for both normal and other towing opera-tions, the greater of the design loads of 5.6.2.3 (1) and 5.6.2.3(2) is to be used.

5.6.2.6.2 The SWL of each shipboard fitting is to bemarked (by weld bead or equivalent) on the deck fittings usedfor towing.

5.6.2.6.3 The above requirements on SWL apply for asingle post basis (no more than one turn of one cable).

5.6.2.6.4 The towing and mooring arrangements planmentioned in 5.6.4 is to define the method of use of towinglines.

5.6.3 Mooring

5.6.3.1 Strength

The strength of shipboard fittings used formooring operations and their supporting hull structures are tocomply with the requirements of this Section.

5.6.3.2 Arrangement

Shipboard fittings for mooring are to be locatedon longitudinals, beams and/or girders, which are part of thedeck construction so as to facilitate efficient distribution of themooring load.

Other arrangements may be accepted (for Pan-ama chocks, etc.) provided the strength is confirmed adequatefor the service.

5.6.3.3 Load considerations

5.6.3.3.1 Unless greater safe working load (SWL) ofshipboard fittings is specified by the applicant, the design loadapplied to shipboard fittings and supporting hull structures isto be 1.25 times the breaking strength of the mooring line ac-cording to Tables 3.1.2-1 and 3.1.2-2 for the ship’s corre-sponding En. (see Note)

NOTE: Side projected area including maximum stacks of deckcargoes is to be taken into account for assessment of lateral windforces, arrangements of tug boats and selection of mooring lines.

5.6.3.3.2 The design load applied to supporting hullstructures for winches, etc. is to be 1.25 times the intendedmaximum brake holding load and, for capstans, 1.25 times themaximum hauling-in force.

5.6.3.3.3 The design load is to be applied through themooring line according to the arrangement shown on the tow-ing and mooring arrangements plan.


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5.6.3.3.4 The method of application of the design load tothe fittings and supporting hull structures is to be taken intoaccount such that the total load need not be more than twicethe design load specified in 5.6.3.3.1 above, i.e. no more thanone turn of one line.

5.6.3.3.5 When a specific SWL is applied for a shipboardfitting at the request of the applicant, by which the design loadis to be greater than the above minimum values, the strengthof the fitting is to be designed using this specific design load.

5.6.3.4 Shipboard fittings

The selection of shipboard fittings is to be madeby the shipyard in accordance with an Industry standard (e.g.ISO3913 Shipbuilding welded steel bollards) accepted by theRegister.

When the shipboard fitting is not selected froman accepted Industry standard, the design load used to assessits strength and its attachment to the ship is to be in accor-dance with 5.6.3.3.

5.6.3.5 Supporting hull structure

5.6.3.5.1 Arrangement

Arrangement of the reinforced members (car-ling) beneath shipboard fittings is to consider any variation ofdirection (horizontally and vertically) of the mooring forces(which is to be not less than the design load as per 5.6.3.3)acting through the arrangement of connection to the shipboardfittings.

5.6.3.5.2 Acting point of mooring force

The acting point of the mooring force on ship-board fittings is to be taken at the attachment point of amooring line or at a change in its direction.

5.6.3.5.3 Allowable stresses

Allowable stresses under the design load condi-tions as specified in 5.6.3.3 are as follows:Normal stress: 100% of the specified minimum yield point ofthe material;Shearing stress: 60% of the specified minimum yield point ofthe material;

No stress concentration factors being taken intoaccount.

Normal stress is the sum of bending stress andaxial stress with the corresponding shearing stress acting per-pendicular to the normal stress.

5.6.3.6 Safe working load (SWL)

5.6.3.6.1 The SWL is not to exceed 80% of the designload per 5.6.3.3.

5.6.3.6.2 The SWL of each shipboard fitting is to bemarked (by weld bead or equivalent) on the deck fittings usedfor mooring.

5.6.3.6.3 The above requirements on SWL apply for asingle post basis (no more than one turn of one cable).

5.6.3.6.4 The towing and mooring arrangements planmentioned in 5.6.4 is to define the method of use of mooringlines.

5.6.4 Towing and mooring arrangements plan

5.6.4.1 The SWL for the intended use for each ship-board fitting is to be noted in the towing and mooring ar-rangements plan available on board for the guidance of theMaster.

5.6.4.2 Information provided on the plan is to include inrespect of each shipboard fitting:

.1 location on the ship;

.2 fitting type;

.3 SWL;

.4 purpose (mooring/harbour towing/escorttowing); and

.5 manner of applying towing or mooringline load including limiting fleet angles.

5.6.4.3 Where the arrangements and details of deck fit-tings and their supporting hull structures are designed basedon the mooring arrangements as permitted in Note 3 to5.6.3.3.1, the following information is to be clearly indicatedon the plan:

.1 the arrangement of mooring lines showingnumber of lines (N), together with

.2 the breaking strength of each mooring line(BS).

This information is to be incorporated into thepilot card in order to provide the pilot proper information onharbour/escorting operations.

5.6.5 Corrosion Addition

The total corrosion addition, tk, in [mm], for bothsides of the hull supporting structure is not to be less than thefollowing values:

- Ships covered by CSR (IACS CommonStructural Rules) for bulk carriers andCSR for double hull oil tankers: total cor-rosion additions defined in these rules

- Other ships: 2.0 mm.

5.6.6 Survey after construction

The condition of deck fittings, their pedestals, ifany, and the hull structures in the vicinity of the fittings are tobe examined in accordance with the Rules. The wastage al-lowances as specified by the Rules are not to exceed the corro-sion addition as specified in 5.6.5.

5.7 EQUIPMENT FOR MOORINGAT SINGLE POINT MOORINGS

5.7.1 Upon request from the owner, Register is pre-pared to certify that the vessel is specially fitted for compli-ance with Section 2.1, 4.2 and 6. of the "Standards for equip-ment employed in the mooring of ships at single point moor-ings" published by the Oil Companies International MarineForum (OCIMF), 1978. See also IACS Rec. No.13.


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5.7.2 The certificate may be issued if:– plans showing the equipment and the ar-

rangement as well as necessary substruc-tures are submitted for approval

– the chain stopper, Smit bracket, or otherdevice for securing the chafing chain to theship and the structure to which it is at-tached are capable of withstanding a loadnot less than the breaking strength of thechain corresponding to the size of the shipas given in Section 6 of the standardsstipulated in 5.1 above and calculations todemonstrate this capability are submitted

– the chain bearing surface of the bow fair-leads described in 6.1 of the standardstipulated in 5.1 above have a diameter atleast seven times that of the associatedchain

– the installation on board the ship is sur-veyed by a Register′s surveyor.

5.8 EMERGENCY TOWINGPROCEDURES ON SHIPS

5.8.1 This paragraph applies to:.1 all passenger ships, not later than 1 Janu-

ary 2010;.2 cargo ships constructed on or after 1

January 2010; and.3 cargo ships constructed before 1 January

2010, not later than 1 January 2012.

5.8.2 Ships shall be provided with a ship-specificemergency towing procedure. Such a procedure shall be car-ried aboard the ship for use in emergency situations and shallbe based on existing arrangements and equipment available onboard the ship.

5.8.3 The procedure** shall include:.1 drawings of fore and aft deck showing

possible emergency towing arrangements;.2 inventory of equipment on board that can

be used for emergency towing;.3 means and methods of communication;

and.4 sample procedures to facilitate the prepa-

ration for and conducting of emergencytowing operations.

** Refer to the Guidelines for owners/operators on preparingemergency towing procedures (MSC.1/Circ.1255).


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6 SIGNAL MASTS


6.1.1 The requirements given in the present section re-fer only to the signal masts, i.e. the masts which are intendedfor carrying the signal means: navigation lights, day signals,antennae, etc.

6.1.2 Arrangement, height and equipment of the signalmasts shall comply with the requirements of the Conventionon the International Regulations for Preventing Collisions atSea, 1972 (COLREGs).

6.1.3 The vibration calculation is recommended to becarried out.

6.2 STAYED MASTS

6.2.1 The outside diameter and the plate thickness atthe heel of the masts made of steel having yield point from215 up to 255 N/mm2 and stayed by two shrouds on each sideof the ship, are not to be less than:

d = 22 l, [mm],t = 0,2 l + 3, [mm],

where:d - outside diameter of the mast at the heel, in

[mm],t - plate thickness at the heel, in [mm],l - mast length, in [m], from the heel to the

shroud eyeplates.The diameter of the mast may be gradually de-

creased upwards to a value of 0,75⋅d at the shroud eyeplates,while the thickness of the mast plates is maintained constantthroughout the length l. The mast length from the shroud eye-plates to the top is not to exceed one third of l.

The mast is to be stayed by the shrouds as fol-lows:

.1 horizontal distance (a) from the deck (orbulwark) stay eyeplate to the transverseplane through the mast stay eyeplate is notto be less than:a = 0,15 h, in [m],

where:h - vertical distance, in [m], from the mast

stay eyeplate to the deck (or bulwark) stayeyeplate,

.2 horizontal distance (b) from the deck (orbulwark) stay eyeplate to the longitudinalplane through the mast stay eyeplate is notto be less than:b = 0,30 h, in [m],

.3 the value of a is not to exceed the value ofb.

6.2.2 The breaking strength of the whole ropes usedfor the mast shrouds as specified in 6.2.1 is not to be less than:

F = 0,49 (l2 + 10l + 25), in [kN]

The loose gear of shrouds (shackles, turnbuck-les, etc.) is to be such that their safe working load is not to beless than 0,25 times the actual breaking strength of the ropesreferred to above.

In all other respects the ropes for the mastshrouds shall meet the requirements of the Rules, Part 25 -Metallic materials, 8.

6.2.3 Where:- the mast is made of high-tensile steel, light

alloys, fibreglass or wood (1st grade woodmust be used),

- the mast is stayed in some way other thanthat specified in 6.2.1,

- in addition to a yard arm, lights, and daysignals, the mast is fitted with otherequipment of considerable weight, such asradar reflectors with platforms for theirservicing, "crow's nests", etc., proceed asspecified in 6.4.

6.2.4 The wire of the shrouds must have a standardquality zinc coating.

6.3 UNSTAYED MASTS

6.3.1 The outer diameter, d, and thickness of the platest at the base of the masts, which are to be made of steel with ayield point between 215 and 255 N/mm2 inclusive, is not to beless than:

( )1

22

4

2

)13674,0(100

13674,0105,5111

3−++⋅

++⋅

⋅++

=al

allld [mm];

dt701

= , [mm],

where:l - length of the mast from bottom to top, in

[m],a - vertical distance from the base of the mast

to the centre of gravity of the ship, in [m].The outer diameter of a mast may decrease so

that at 0,75 l from the base is 0,5 d. The thickness of the mastplates is not to be less than 4 mm. The heel of the mast mustbe rigidly fixed to the deck from all directions.

6.3.2 Where:

- the mast is made of high-tensile steel, lightalloys, fibreglass or wood (1st grade woodmust be used),

- in addition to a yard arm, lights, and daysignals, the mast is fitted with otherequipment of considerable weight, such asradar reflectors with platforms for theirservicing, etc., proceed as specified in 6.4.


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6.4 MASTS OF SPECIALCONSTRUCTION

6.4.1 In the cases specified in 6.2.3 and 6.3.2 as wellas where bipod, tripod and other similar masts are installed,detailed strength calculations of these masts are to be carriedout. These calculations are to be submitted for the approval.

6.4.2 The calculations are to be performed on the as-sumption that each part of the mast is affected by a horizontalforce:

( ) 32

2104 −⋅

+++= θθθθπ cospAsingmsinrz

TmF iiiii

, [kN]

where:mi = mass of part (i), in [kg],zi = elevation of the centre of gravity of part

(i) above that of the ship, in [m],Ai = projected lateral area of part (i), in [m2],T = rolling or pitching period, in sec.,θ = amplitude of roll or pitch, maximum, in

radians,r = wave half height, in [m],p = specified wind pressure, in [N/m2]p = 1960 N/m2.The calculations are to be carried out both for

rolling and pitching of the ship; r being taken as equal to L/40,where L is the ship's length, in [m], and θ, in radians, as corre-sponding angle of 40o at roll and of 5o at pitch.

6.4.3 Under load specified in 6.4.2 the stresses in partsof the mast are not to exceed 0,7 times the yield stress of thematerial if made of metal and are not to exceed 12 N/mm2 ifmade of wood.

The safety factor of the standing rope under thesame load is not to be less than 3.


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7 OPENINGS IN HULL,SUPERSTRUCTURES ANDDECKHOUSES AND THEIR

CLOSING APPLIANCES


7.1.1 The requirements of the present section apply toships of unrestricted service as well as to ships of restricted ar-eas of navigation 2 and 3. The requirements for ships of re-stricted areas of navigation 4, 5, 6, 7 and 8 may be relaxed, theextent of relaxation is to be specially considered by the Reg-ister in each case depending upon the type of ship, navigationarea, strength, freeboard and stability of ship.

7.1.2 Departures from these requirements may bepermitted for the ships to which a greater than minimum free-board is assigned on condition that the Register is satisfiedwith safety conditions provided.

7.1.3 The arrangement of openings and their closingappliances in the hull, superstructures and deckhouses shallalso comply with the requirements of the Rules, Part 17 - Fireprotection, Part 12 - Electrical equipment, ICLL, 1966 andPart 24 - Non-metallic materials.

7.1.4 As far as deck openings are considered, the fol-lowing two positions are distinguished in the present section:

.1 Position 1:.1 upon exposed freeboard and raised

quarter decks;.2 upon exposed superstructure decks

situated forward of a point located aquarter of the ship's length from theforward perpendicular;

.2 Position 2:.1 upon exposed superstructure decks

situated abaft a quarter of the ship'slength from the forward perpendicularand located at least one standard heightof superstructure above the freeboarddeck;

.2 upon exposed superstructure deckssituated forward of a point located aquarter of the ship's length from theforward perpendicular and located atleast two standard heights of super-structure above the freeboard deck.

7.1.5 The heights of coamings in ships of restrictedarea of navigation are to be approved by the Administration.

7.1.6 The height of coamings specified in the presentsection is measured from the upper surface of the steel deckplating or from the upper surface of the wood or other sheath-ing, if fitted.

7.1.7 In supply vessels the access to the spaces situ-ated below the open cargo deck shall preferably be providedfrom the location inside the enclosed superstructure or deck-house or from the location above the superstructure deck ordeckhouse top.

7.1.8 For the ships indicated in 7.1.7 the arrangementof companion or other hatches on the open cargo deck leadingto the spaces below this deck is subject to special considera-tion, taking account of the degree of protection of thesehatches from possible damage during cargo handling opera-tions as well as the volume of spaces flooded in case of dam-age to the hatch.

7.1.9 All external openings leading to compartmentsassumed intact in the damage stability calculation, which arebellow the final damage water line, are required to be water-tight. The closing appliances of these openings are to be ofsufficient strength and, except for cargo hatch covers, are to befitted with indicators (open-closed) on the bridge.

7.1.10 Openings in the shell plating bellow the bulk-head deck are to be kept permanently closed while at sea. Ifany of these openings are accessible during the voyage, theyare to be fitted with a device which prevents unauthorisedopening.

7.1.11 Notwithstanding the requirements of 7.1.10, theRegister may authorise that particular doors may be opened atthe discretion of the master, if necessary for the operation ofthe ship and provided that the ship safety is not impaired.

7.1.11 Other closing appliances which are kept perma-nently closed at sea to ensure the watertight integrity of exter-nal openings are to be provided with a notice affixed to eachappliance to the effect that it is to be kept closed. Manholesfitted with closely bolted covers need not to be so marked.

7.1.12 The number of openings in the shell plating ofthe passenger ships is to be reduced to the minimum compati-ble with the design and proper working of the ship.

7.1.13 The arrangement and efficiency of the means forclosing any opening in the shell plating are to be consistentwith its intended purpose and the position in which it is fittedand generally to the satisfaction of the Register.

7.1.14 The number of scuppers, sanitary discharges andother similar openings in the shell plating is to be reduced tothe minimum either by making each discharge serve for asmany as possible of the sanitary and other pipes, or in anyother satisfactory manner.

7.1.15 All inlets and discharges in the shell plating areto be fitted with efficient and accessible arrangements for pre-venting the accidental admission of water into the ship.

7.1.16 Subject to the requirements of the ICLL, 1996,and except as provided in 7.1.18, each separate discharge ledthrough the shell plating from spaces below the bulkhead deckof passenger ships and the freeboard deck of cargo ships is tobe provided with either one automatic non-return valve fittedwith a positive means of closing it from above the bulkheaddeck or with two automatic non-return valves without positivemeans of closing, provided that the inboard valve is situatedabove the deepest subdivision draught and is always accessi-ble for examination under service conditions. Where a valvewith positive means of closing is fitted, the operating positionabove the bulkhead deck is to always be readily accessible andmeans are to be provided for indicating whether the valve isopen or closed.

7.1.17 The requirements of the ICLL, 1996, shall applyto discharges led through the shell plating from spaces above


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the bulkhead deck of passenger ships and the freeboard deckof cargo ships.

7.1.18 Machinery space, main and auxiliary sea inletsand discharges in connection with the operation of machineryare to be fitted with readily accessible valves between thepipes and the shell plating or between the pipes and fabricatedboxes attached to the shell plating. In manned machineryspaces the valves may be controlled locally and are to be pro-vided with indicators showing whether they are open orclosed.

7.1.19 Moving parts penetrating the shell plating belowthe deepest subdivision draught are to be fitted with a water-tight sealing arrangement acceptable to the Register. The in-board gland is to be located within a watertight space of suchvolume that, if flooded, the bulkhead deck is not to be sub-merged. The Register may require that if such compartment isflooded, essential or emergency power and lighting, internalcommunication, signals or other emergency devices must re-main available in other parts of the ship.

7.1.20 All shell fittings and valves required by these re-quirements are to be of steel, bronze or other approved ductilematerial. Valves of ordinary cast iron or similar material arenot acceptable. All pipes to which this regulation refers are tobe of steel or other equivalent material to the satisfaction ofthe Register.

7.1.21 Gangway, cargo and fuelling ports fitted belowthe bulkhead deck of passenger ships and the freeboard deckof cargo ships are to be watertight and in no case be so fittedas to have their lowest point below the deepest subdivisiondraught.

7.1.22 The inboard opening of each ash-chute, rubbish-chute, etc., is to be fitted with an efficient cover.

7.1.23 If the inboard opening is situated below thebulkhead deck of passenger ships and the freeboard deck ofcargo ships, the cover is to be watertight and, in addition, anautomatic non-return valve is to be fitted in the chute in aneasily accessible position above the deepest subdivisiondraught.

7.1.24 It is recommended that cargo ports or similaropenings below the uppermost load specified in Regulation21(2) of ICCL, 1996 may be accepted submerged providedthe safety of the ship is in no way impaired. It is consideredthat the fitting of a second door of equivalent strength andwatertightness is one acceptable arrangement. In that caseleakage detection device should be provided in the compart-ment between the two doors. Further, drainage of this com-partment to the bilges controlled by an easily accessible screwdown valve, should be arranged. The outer door should pref-erably open outwards. See IACS unified interpretation LL21.

7.2 SIDESCUTTLES ANDWINDOWS

7.2.1 General

7.2.1.1 The requirements in 7.2.1 to 7.2.4 apply tosidescuttles and rectangular windows providing light and air,located in positions which are exposed to the action of seaand/or bad weather.

7.2.1.2 Sidescuttles are round or oval openings with anarea not exceeding 0.16 m2. Round or oval openings havingarea exceeding 0.16 m2 are to be treated as windows.

7.2.1.3 Windows are rectangular openings generally,having a radius at each corner relative to window size in ac-cordance with recognised national or international standards,and round or oval openings with an area exceeding 0.16 m2.

7.2.1.4 The number of sidescuttles in the shell platingbelow the freeboard deck is to be reduced to a minimum com-patible with the design and proper working of the ship.

Fishing vessels mooring alongside each other orother ships at sea are not to have sidescuttles under freeboarddeck in the mooring zone, wherever possible. If in this zoneside scuttles are fitted in the shell plating, they are to be so po-sitioned that the possibility of their damage during mooringoperations is excluded.

No sidescuttles are permitted within the bounda-ries of the ice belt of the shell plating specified in the Rules,Part 2 - Hull, 14, in icebreakers and ships with ice strength-ening.

7.2.1.5 Sidescuttles and windows together with theirglasses, deadlights and storm covers, if fitted, are to be of ap-proved design and substantial construction in accordance with,or equivalent to, recognised national or international stan-dards.

Non-metallic frames are not acceptable. The useof ordinary cast iron is not allowed for sidescuttles below thefreeboard deck.

7.2.1.6 All sidescuttles the sills of which are below thebulkhead deck of passenger ships and the freeboard deck ofcargo ships, as permitted by paragraph 7.2.2.1, are to be ofsuch construction as will effectively prevent any personopening them without the consent of the master of the ship.

Sidescuttles and their deadlights which are notaccessible during navigation are to be closed and secured be-fore ship leaves the port.

7.2.1.7 Side scuttles to the following spaces shall befitted with efficient hinged inside deadlights:

(a) spaces below freeboard deck(b) spaces within the first tier of enclosed su-

perstructures(c) first tier deckhouses on the freeboard deck

protecting openings leading below or con-sidered buoyant in stability calculations.

The deadlights shall be capable of being effec-tively closed and secured watertight if fitted below freeboarddeck and weathertight if fitted above.

Efficient hinged inside deadlights so arrangedthat they can be easily and effectively closed and secured wa-tertight, are to be fitted to all sidescuttles except that abaft oneeighth of the ship's length from the forward perpendicular andabove a line drawn parallel to the bulkhead deck at side andhaving its lowest point at a height of 3.7 m plus 2.5% of thebreadth of the ship above the deepest subdivision draught, thedeadlights may be portable in passenger accommodation otherthan that for steerage passengers, unless the deadlights are re-quired by the ICLL, 1996, to be permanently attached in theirproper positions. Such portable deadlights are to be stowedadjacent to the sidescuttles they serve.


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7.2.2 Position and opening arrangement

7.2.2.1 No sidescuttle is to be fitted in such position thatits sill is below a line drawn parallel to the bulkhead deck atside and having its lowest point 0.025⋅B above the summerload waterline (or timber summer load waterline if assigned),or 0.5 m, whichever is the greater.

If the length of the ship is less than 24 m, thespecified distance may be reduced to 0.3 m for ships of navi-gation area 4 and 5 and to 0.15 m for ships of navigation area6, 7 and 8.

7.2.2.2 No sidescuttles is to be fitted in any spaceswhich are appropriated exclusively for carriage of cargo orcoal.

Sidescuttles may, however, be fitted in spacesappropriated alternatively for carriage of cargo or passengers,but they are to be of such construction as will effectively pre-vent any person opening them or their deadlights without theconsent of the master.

If cargo is carried in such spaces, the sidescuttlesand their deadlights are to be closed watertight and locked be-fore the cargo is shipped.

7.2.2.3 Side scuttles shall be of the non-opening type inships subject to damage stability regulations, if calculationsindicate that they would become immersed by any intermedi-ate stage of flooding or the final equilibrium waterplane in anyrequired damage case.

7.2.2.4 In ships having several decks above the bulk-head deck, such as passengers ships, the arrangement of sides-cuttles and rectangular windows is to be specially consideredby the Register in each case. Special consideration is to begiven to the ship side up to the upper deck and the front bulk-head of the superstructure.

7.2.2.5 Automatic ventilating sidescuttles are not to befitted in the shell plating below the bulkhead deck without thespecial sanction of the Register.

7.2.2.6 Windows are not to be fitted below the freeboarddeck, in first tier end bulkheads or sides of enclosed super-structures and in first tier deckhouses considered as beingbuoyant in the stability calculations or protecting openingsleading below.

In the front bulkhead of a superstructure situatedon the upper deck, in case of substantially increased freeboard,rectangular windows with permanently fitted storm covers areacceptable.

7.2.2.7 Side scuttles and windows at the side shell in thesecond tier, protecting direct access below or consideredbuoyant in the stability calculations, shall be provided with ef-ficient hinged inside deadlights capable of being effectivelyclosed and secured weathertight.

7.2.2.8 Side scuttles and windows set inboard from theside shell in the second tier, protecting direct access below tospaces listed in 7.2.1.7, shall be provided with either efficienthinged inside deadlights or, where they are accessible, perma-nently attached external storm covers of approved design andof substantial construction and capable of being effectivelyclosed and secured weathertight.

7.2.2.9 Cabin bulkheads and doors in the second tierseparating side scuttles and windows from a direct access

leading below may be accepted in place of deadlights or stormcovers fitted to the side scuttles and windows.

7.2.2.10 Deckhouses situated on a raised quarter deck oron the deck of a superstructure of less than standard height oron the deck of a deckhouse of less than standard height, maybe regarded as being in the second tier as far as the provisionof deadlights is concerned, provided the height of the raisedquarter deck, superstructure or deckhouse is equal to, orgreater than, the standard quarter deck height.

7.2.2.11 Fixed or opening skylights shall have glassthickness appropriate to their size and position as required forside scuttles and windows. Skylight glasses in any positionshall be protected from mechanical damage and where fitted inpositions 1 or 2, shall be provided with robust deadlights orstorm covers permanently attached. See also IASC unified in-terpretation LL62.

7.2.3 Glasses

7.2.3.1 In general, toughened glasses with frames ofspecial type are to be used in compliance with, or equivalentto, recognised national or international standards, see theRules, Part 24 - Non-metallic materials, 3.7.

The use of clear plate glasses is to be speciallyconsidered by the Register in each case.

7.2.3.2 The thickness of toughened glasses in sidescut-tles is not to be less than that obtained from Table 7.2.3.2-1.

Table 7.2.3.2-1

Thickness [mm]Clear light di-ameter ofsidescuttle

[mm]

Type A Heavyseries

Type BMedium

series

Type C Lightseries

200 10 8 6250 12 8 6300 15 10 8350 15 12 8400 19 12 10

450 Notapplicable 15 10

Type A, B or C sidescuttles are to be adoptedaccording to the requirements of Table 7.2.3.2-2, where:

- zone 1 is the zone comprised between a line,parallel to the sheer profile, with its lowestpoints at a distance above the summer load wa-terline equal to 0.025 B, or 0.5 m, whichever isthe greater, and a line parallel to the previousone located 1.4 m above it;

- zone 2 is the zone located above zone 1 andbounded at the top by the freeboard deck;

- zone 4 is the second tier of superstructures ordeckhouses;

- zone 5 is the third and higher tiers of super-structures or deckhouses;

- exposed zones are the boundaries of superstruc-tures or deckhouses set in from the ship’s side ata distance less than or equal to 0.04 B;


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- unexposed zones are the boundaries of super-structures or deckhouses set in from the ship’sside at a distance greater than 0.04 B.

7.2.3.3 Ships of navigation area 4 and 5, having lengthless than 24 m, may be fitted with sidescuttles type B and typeC instead of those type A and type B required in Table 7.2.3.2-2.

Ships of navigation area 6 and 7 may be fittedwith sidescuttles type B and type C instead of those type Aand type B required in Table 7.2.3.2-2.

In ships of navigation area 8 all fitted sidescut-tles may be type C.


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Table 7.2.3.2-2

Zone Aft of 0.875 L from the aft end Forward of 0.875 Lfrom the aft end

5 Type C Type BProtecting openings giving direct access to spaces below the freeboard deck:

Type B4

Not protecting openings giving direct access to spaces below the freeboard deck:Type C

Type B

Exposed zones Type BProtecting openings giving direct access to spaces belowthe freeboard deck: Type B3

Unexposed zonesNot protecting openings giving direct access to spacesbelow the freeboard deck: Type C

Type B

2 Type B Type A1 Type A Type A

7.2.3.4. The thickness of toughened glasses in rectangu-lar windows is not to be less than that obtained from Table7.2.3.4-1.

Dimensions of rectangular windows other thanthose in Table 7.2.3.4-1 is to be specially considered by theRegister in each case.

7.2.3.5 The thickness of glasses forming screen bulk-heads on the side of enclosed promenade spaces and that forrectangular windows in the boundaries of deckhouses, whichare protected by such screen bulkheads, is to be specially con-sidered by the Register in each case.

The Register may require both limitations onsize of rectangular windows and use of glasses of increasedthickness in way of front bulkheads, which are exposed toheavy sea.

7.2.4 Deadlights arrangement

7.2.4.1 Sidescuttles in the following positions are to befitted with efficient, hinged inside deadlights so arranged thatthey can be easily and effectively closed and secured water-tight:

- in the shell plating below freeboard deck;- in front bulkheads of enclosed superstruc-

tures and deckhouses of the first tier;- in front bulkheads of enclosed superstruc-

tures and deckhouses of the second tierwithin 0.25 L from the forward perpen-dicular;

- in the first tier of enclosed superstructuresand deckhouses on freeboard deck pro-tecting openings leading below or consid-ered buoyant in stability calculations.

Table 7.2.3.4-1

Thickness, [mm]

Nominal size(clear light)of rectangu-lar window

[mm2]

Unexposedzone of firsttier, exposed

zone of secondtier

Unexposedzone of

second tier,exposed zone

of third tier andabove

Minimumnumber of

closingappliances ofopening typerectangularwindows

300 x 425 10 8 4

355 x 500 10 8 4

400 x 560 12 8 4

450 x 630 12 8 4

500 x 710 15 10 6

560 x 800 15 10 6

900 x 630 19 12 6

1000 x 710 19 12 8

1100 x 800 Not applicable 15 8

7.3 FLUSH SCUTTLES

7.3.1 Flush scuttles in positions 1 or 2 are to be closedby substantial covers capable of being made watertight. Unlesssecured by closely spaced bolts, the covers are to be perma-nently attached.

7.3.2 The largest of clear dimensions of the flushscuttles is not to be over 200 mm, with the glass being at least15 mm in thickness. The flush scuttles are to be fastened to themetal deck plating by means of frames.


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7.4 SHELL DOORS

7.4.1 Bow doors and inner doors

7.4.1.1 General

7.4.1.1.1 The requirements of this head of the Rules applyto the arrangement, strength and securing of bow doors andinner doors leading to a complete or long forward enclosedsuperstructure, or to a long non-enclosed superstructure, wherefitted to attain minimum bow height equivalence.

The requirements apply to all ro-ro passengerships and ro-ro cargo ships engaged on international voyagesand also to ro-ro passenger ships and ro-ro cargo ships en-gaged only in domestic (non-international) voyages, exceptwhere specifically indicated otherwise herein.

The requirements are not applicable to highspeed, light displacement craft as defined in the IMO Code ofSafety for High Speed Craft.

Two types of bow door are provided for:Visor doors opened by rotating upwards and

outwards about a horizontal axis through two or more hingeslocated near the top of the door and connected to the primarystructure of the door by longitudinally arranged lifting arms,

Side-opening doors either by rotating outwardsabout a vertical axis through two or more hinges located nearthe outboard edges or by horizontal translation by means oflinking arms arranged with pivoted attachments to the doorand the ship.

Other types of bow doors are to be speciallyconsidered by the Register.

7.4.1.1.2 Bow doors are to be situated above the freeboarddeck. A watertight recess in the freeboard deck located for-ward of the collision bulkhead and above the deepest waterlinefitted for arrangement of ramps or other related mechanicaldevices may be regarded as a part of the freeboard deck for thepurpose of this requirement.

7.4.1.1.3 Inner doors are to be fitted. The inner door is tobe part of the collision bulkhead. The inner door need not befitted directly above the bulkhead below, provided that it is lo-cated within the limits specified for the position of the colli-sion bulkhead, refer to Regulation II-1/12 of the SOLAS Con-vention. A vehicle ramp may be arranged for this purpose,provided its position complies with Regulation II-1/12 of theSOLAS Convention. If this is not possible a separate innerweathertight door are to be installed, as far as practicablewithin the limits specified for the position of the collisionbulkhead.

7.4.1.1.4 Bow doors are to be so fitted as to ensure tight-ness consistent with operational conditions and to give effec-tive protection to inner doors. Inner doors forming of the colli-sion bulkhead are to be weathertight over the full height of thecargo space and arranged with fixed sealing supports on theaft side of the doors.

7.4.1.1.5 Bow doors and inner doors are to be arranged soas to preclude the possibility of the bow door causing struc-tural damage to the inner door or to the collision bulkhead inthe case of damage to or detachment of the bow door. If this isnot possible, a separate inner weathertight door is to be in-stalled, as indicated in 7.4.1.1.3.

7.4.1.1.6 For the purpose of satisfaction of the require-ments for inner doors, vehicles are to be effectively lashed andsecured against movement in stowed position.

7.4.1.1.7 DefinitionsSecuring device: device used to keep the door closed

by preventing it from rotating aboutits hinges.

Supporting device: a device used to transmit external orinternal loads from the door to a se-curing device and from the securingdevice to the ship's structure, or adevice other than a securing device,such as a hinge, stopper or otherfixed device, transmits loads fromthe door to the ship's structure.

Locking device: a device that locks a securing devicein the closed position.

Ro-ro passenger ship: a passenger ship with ro-ro spaces orspecial category spaces.

Ro-ro spaces: are spaces not normally subdividedin any way and normally extendingto either a substantial length or theentire length of the ship, in whichmotor vehicles with fuel in theirtanks for their own propulsion and/orgoods (packaged or in bulk, in or onrail or road cars, vehicles (includingroad or rail tankers), trailers, con-tainers, pallets, demountable tanks orin or on similar stowage units or,other receptacles) can be loaded andunloaded normally in a horizontal di-rection.

Special category spaces: are those enclosed vehicle spacesabove or below the bulkhead deck,into and from which vehicles can bedriven and to which passengers haveaccess. Special category spaces maybe accommodated on more than onedeck provided that the total overallclear height for vehicles does not ex-ceed 10m.

7.4.1.2 Strength criteria

7.4.1.2.1 Scantlings of the primary member, securing andsupporting devices of bow doors and inner doors are to be de-termined to withstand the design loads defined in 7.4.1.3, us-ing the following permissible stresses:

- shear stress: τ = 80/k [N/mm2]- bending stress: σ = 120/k [N/mm2]- equivalent stress:

k/e 1503 22 =+= τσσ [N/mm2]

where k is the material factor as given in theRules, Part 2 - Hull, 1.4, but is not to be taken less than 0,72.

7.4.1.2.2 The buckling strength of primary members is tobe verified as being adequate.

7.4.1.2.3 For steel to steel bearings in securing and sup-porting devices, the nominal bearing pressure calculated bydividing the design force by the projected bearing area is not


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to exceed 0,8 ⋅σF, where σF is the yield stress of the bearingmaterial. For other bearing materials, the permissible bearingpressure is to be determined according to the manufacturer'sspecification.

7.4.1.2.4 The arrangement of securing and supporting de-vices is to be such that threaded bolts do not carry supportforces. The maximum tension in way of threads of bolts notcarrying support forces is not to exceed 125/k [N/mm2].

7.4.1.3 Design loads

7.4.1.3.1 The design external pressure, in [kN/m2], to beconsidered for the scantlings of primary members, securingand supporting devices of bow doors is not to be less than:

pe = 2,75⋅λ ⋅ CH ⋅ (0,22+0,15⋅ tanα)(0,4 ⋅ v ⋅ sinβ +0,6 ⋅ L )2

where:v = contractual ship's speed, in [knots];L = ship's length, in [m], but need not be

taken greater than 200 metres;λ = coefficient depending on the area where

the ship is intended to be operated:λ = 1 for sailing area 1 and 2;λ = 0,8 for sailing area 3 and 4;λ = 0,5 for sailing area 5, 6, 7 and 8.

CH = 0,0125 L, for L < 80 m1,00, for L ≥ 80 m

α = flare angle at the point to be considered,defined as the angle between a verticalline and the tangent to the side shellplating, measured in a vertical planenormal to the horizontal tangent to theshell plating (see Figure 7.4.1.3.2);

β = entry angle at the point to be considered,defined as the angle between a longitu-dinal line parallel to the centreline andthe tangent to the shell plating in a hori-zontal plane (see Figure 7.4.1.3.2).

7.4.1.3.2 The design external forces, in [kN], consideredfor the scantlings of securing and supporting devices of bowdoors is not to be less than:

Fx = pe ⋅ AxFy = pe ⋅ AyFz = pe ⋅ Az

where:Ax = area, in [m2], of the transverse vertical

projection of the door between the levelsof the bottom of the door and the top ofthe upper deck bulwark, or between thebottom of the door and the top of thedoor, including the bulwark, where it ispart of the door, whichever is the lesser.Where the flare angle of the bulwark isat least 15° less than the flare angle ofthe adjacent shell plating, the heightfrom the bottom of the door may bemeasured to the upper deck or to the topof the door, whichever is lesser. In de-termining the height from the bottom ofthe door to the upper deck or to the top

of the door, the bulwark is to be ex-cluded.;

Ay = area, in [m], of the longitudinal verticalprojection of the door between the levelsof the bottom of the door and the top ofthe upper deck bulwark, or between thebottom of the door and the top of thedoor, including the bulwark, where it ispart of the door, whichever is the lesser.Where the flare angle of the bulwark isat least 15° less than the flare angle ofthe adjacent shell plating, the heightfrom the bottom of the door may bemeasured to the upper deck or to the topof the door, whichever is lesser.

Az = area, in [m2], of the horizontal projectionof the door between the levels of thebottom of the door and the top of the up-per deck bulwark, or between the bottomof the door and the top of the door, in-cluding the bulwark, where it is part ofthe door, whichever is the lesser. Wherethe flare angle of the bulwark is at least15° less than the flare angle of the adja-cent shell plating, the height from thebottom of the door may be measured tothe upper deck or to the top of the door,whichever is lesser.

h = height, in [m], of the door between thelevels of the bottom of the door and theupper deck or between the bottom of thedoor and the top of the door, whicheveris the lesser;

l = length, in [m], of the door at a height h/2above the bottom of the door;

w = breadth, in [m], of the door at a heighth/2 above the bottom of the door;

pe = external pressure, in [kN/m2], as given in7.4.1.3.1 with angles α and β defined asfollows:

α = flare angle measure at the point on thebow door, l/2 aft of the stem line on theplane h/2 above the bottom of the door,as shown in Figure 7.4.1.3.2;

β = entry angle measured at the same pointas α.


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Figure 7.4.1.3.2 Definition of α and β

For bow doors, including bulwark, of unusualform or proportions, e.g. ships with a rounded nose and largestem angles, the areas and angles used for determination of thedesign values of external forces may require to be speciallyconsidered.

7.4.1.3.3 For visor doors the closing moment My underexternal loads, in [kNm], is to be taken as:

My = Fx ⋅ a + 10 ⋅ W ⋅ c + Fz ⋅ bwhere:

W = mass of the visor door, in [t];a = vertical distance, in [m], from visor pivot

to the centroid of the transverse verticalprojected area of the visor door, asshown in Figure 7.4.1.3.3;

b = horizontal distance, in [m], from visorpivot to the centroid of the horizontalprojected area of the visor door, asshown in Figure 7.4.1.3.3;

c = horizontal distance, in [m], from visorpivot to the centre of gravity of visormass, as shown in Figure 7.4.1.3.3.

Figure 7.4.1.3.3 Bow Door of Visor Type

7.4.1.3.4 The lifting arms of a visor door and its supportsare to be dimensioned for the static and dynamic forces ap-plied during the lifting and lowering operations, and a mini-mum wind pressure of 1,5 kN/m2 is to be taken into account.

7.4.1.3.5 The design external pressure pc, in [kN/m2], con-sidered for the scantlings of primary members, securing andsupporting devices and surrounding structure of inner doors isto be taken as the greater of the following:

- pe = 0,45 ⋅ L ;- hydrostatic pressure ph = 10 ⋅ h, where h is

the distance, in [m], from the load point tothe top of the cargo space;

where L is the ship's length, as defined in 7.4.1.3.1.

7.4.1.3.6 The design internal pressure pi, in [kN/m2], con-sidered for the scantlings of securing devices of inner doors isnot to be less than 25.

7.4.1.4 Scantlings of bow and inner doors

7.4.1.4.1 The strength of bow doors is to be commensu-rate with that of the surrounding structure.

7.4.1.4.2 Bow doors are to be adequately stiffened andmeans are to be provided to prevent lateral or vertical move-ment of the doors when closed. For visor doors adequatestrength for the opening and closing operations is to be pro-vided in the connections of the lifting arms to the door struc-ture and to the ship structure.

7.4.1.4.3 The thickness of the bow door plating is not tobe less than required for the side shell plating, using bow doorstiffener spacing, but in no case less than the minimum re-quired thickness of fore end shell plating.

7.4.1.4.4 The section modulus of horizontal or verticalstiffeners of bow doors is not to be less than that required forfore end framing. Consideration is to be given, where neces-sary, to differences in fixity between ship's frames and bowdoors stiffeners.

7.4.1.4.5 The stiffener webs of bow doors are to have anet sectional area, in [cm2], not less than:

10kQA ⋅

=

where:Q = shear force, in [kN], in the stiffener cal-

culated by using uniformly distributedexternal pressure pe as given in7.4.1.3.1.

7.4.1.4.6 The bow door secondary stiffeners are to besupported by primary members constituting the main stiffen-ing of the door.

The primary members of the bow door and thehull structure in way are to have sufficient stiffness to ensureintegrity of the boundary support of the door.

Scantlings of the primary members of the bowand inner doors are generally to be supported by directstrength calculations in association with the external pressuregiven in 7.4.1.3.1 and 7.4.1.3.5, respectively, and permissiblestress given in 7.4.1.2.1. Normally, formulae for simple beamtheory may be applied to determine the bending stress. Mem-bers are to be considered to have simply supported end con-nections.


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7.4.1.4.7 Where inner doors also serve as a vehicle ramp,the scantlings are not to be less than those required for vehicledecks.

7.4.1.4.8 The distribution of the forces acting on the se-curing and supporting devices of inner doors is generally to besupported by direct calculations taking into account the flexi-bility of the structure and the actual position and stiffness ofthe supports.

7.4.1.5 Securing and supporting of bow doors

7.4.1.5.1 Bow doors are to be fitted with adequate meansof securing and supporting so as to be commensurate with thestrength and stiffness of the surrounding structure. The hullsupporting structure in way of the bow doors is to be suitablefor the same design loads and design stress as the securing andsupporting devices. Where packing is required, the packingmaterial is to be of a comparatively soft type, and the sup-porting forces are to be carried by the steel structure only.Maximum design clearance between securing and supportingdevices is not generally to exceed 3 mm.

A means are to be provided for mechanicallyfixing the door in the open position.

7.4.1.5.2 Only the active supporting and securing deviceshaving an effective stiffness in the relevant direction are to beincluded and considered to calculate the reaction forces actingon the devices. Small and/or flexible devices such as cleatsintended to provide load compression of the packing materialare not generally to be included in the calculations called forin 7.4.1.5.8. The number of securing and supporting devices isgenerally to be the minimum practical whilst taking into ac-count the requirements for redundant provision given in7.4.1.5.9 and 7.4.1.5.10 and the available space for adequatesupport in the hull structure.

7.4.1.5.3 For opening outwards visor doors, the pivot ar-rangement is generally to be such that the visor is self closingunder external loads, that is My > 0. Moreover, the closingmoment My as given in 7.4.1.3.3 is not to be less than:

My0 = 10 ⋅ W ⋅ c + 0,1 ⋅ ( )( )2222zx FFba ++

7.4.1.5.4 Securing and supporting devices are to be ade-quately designed so that they can withstand the reaction forceswithin the permissible stresses given in 7.4.1.3.1.

7.4.1.5.5 For visor doors the reaction forces applied on theeffective securing and supporting devices assuming the dooras a rigid body are determined for the following combinationof external loads acting simultaneously together with the selfweight of the door:

a) case 1 Fx and Fz ;b) case 2 0,7⋅Fy acting on each side sepa-

rately together with 0,7⋅Fx and0,7⋅Fz;

where Fx, Fy and Fz are determined as indicatedin 7.4.1.3.2 and applied at the centroid of projected areas.

7.4.1.5.6 For side-opening doors the reaction forces ap-plied on the effective securing and supporting devices assum-ing the door as a rigid body are determined for the following

combination of external loads acting simultaneously togetherwith the self weight of the door:

a) case 1 Fx, Fy and Fz acting on bothdoors;

b) case 2 0,7⋅Fx and 0,7⋅Fz acting on bothdoors and 0,7⋅Fy acting on eachdoor separately;

where Fx, Fy and Fz are determined as indicatedin 7.4.1.3.2 and applied at the centroid of projected areas.

7.4.1.5.7 The support forces as determined according to7.4.1.5.5 a) and b) shall generally give rise to a zero momentabout the transverse axis through the centroid of the area Ax.For visor doors, longitudinal reaction forces of pin and/orwedge supports at the door base contributing to this momentare not to be of the forward direction.

7.4.1.5.8 The distribution of the reaction forces acting onthe securing and supporting devices may require to be sup-ported by direct calculations taking into account the flexibilityof the hull structure and the actual position and stiffness of thesupports.

7.4.1.5.9 The arrangement of securing and supporting de-vices in way of these securing devices is to be designed withredundancy so that in the event of failure of any single secur-ing or supporting device the remaining devices are capable towithstand the reaction forces without exceeding by more than20 percent the permissible stresses as given in 7.4.1.2.1.

7.4.1.5.10 For visor doors, two securing devices are to beprovided at the lower part of the door, each capable of pro-viding the full reaction force required to prevent opening ofthe door within the permissible stresses given in 7.4.1.2.1. Theopening moment Mo, in [kNm], to be balanced by this reactionforce, is not to be taken less than:

Mo = 10 ⋅ W ⋅ d + 5 ⋅ Ax ⋅ a

where:

d = vertical distance, in [m], from the hingeaxis to the centre of gravity of the door,as shown in Figure 7.4.1.3.3;

a = as defined in 7.4.1.3.3.

7.4.1.5.11 For visor doors, the securing and supporting de-vices excluding the hinges are to be capable of resisting thevertical design force (Fz - 10 ⋅ W), in [kN], within the permis-sible stresses given in 7.4.1.2.1.

7.4.1.5.12 All load transmitting elements in the design loadpath, from door through securing and supporting devices intothe ship structure, including welded connections, are to be tothe same strength standard as required for the securing andsupporting devices. These elements include pins, supportingbrackets and back-up brackets.

7.4.1.5.13 For side-opening doors, thrust bearing has to beprovided in way of girder ends at the closing of the two leavesto prevent one leaf to shift towards the other one under effectof unsymmetrical pressure (see example of Figure 7.4.1.5.13).Each part of the thrust bearing has to be kept secured on theother part by means of securing devices. Any other arrange-ment serving the same purpose may be proposed.


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Figure 7.4.1.5.13Thrust Bearing

7.4.1.6 Securing and locking arrangement

7.4.1.6.1 Securing devices are to be simple to operate andeasily accessible. Securing devices are to be equipped withmechanical locking arrangement (self locking or separate ar-rangement), or be of the gravity type. The opening and closingsystems as well as securing and locking devices are to be in-terlocked in such a way that can only operate in the proper se-quence.

7.4.1.6.2 Bow doors and inner doors giving access to ve-hicle decks are to be provided with an arrangement for remotecontrol, from a position above the freeboard deck, of:

- the closing and opening of the doors, and- associated securing and locking devices

for every door.Indication of the open/closed position of every

securing and locking device is to be provided at the remotecontrol stations. The operating panels for operation of doorsare to be inaccessible to unauthorised persons. A notice plate,giving instructions to the effect that all securing devices are tobe closed and locked before leaving harbour, is to be placed ateach operating panel and is to be supplemented by warningindicator lights.

7.4.1.6.3 Where hydraulic devices are applied, the systemis to be mechanically lockable in closed position. This meansthat, in the event of loss of the hydraulic fluid, the securingdevices remain locked.

The hydraulic system for securing and lockingdevices is to be isolated from other hydraulic circuits, when inclosed position.

7.4.1.6.4 Separate indicator lights and audible alarms areto be provided on the navigation bridge and on the operatingpanel to show that the bow door and inner door are closed andthat their securing and locking devices are properly positioned.

The indication panel is to be provided with alamp test function. It is not to be possible to turn off the indi-cator light.

7.4.1.6.5 The indicator system is to be designed on thefail safe principle and is to show by visual alarms if the dooris not fully closed and not fully locked and by audible alarmsif securing devices become open or locking devices becomeunsecured. The power supply for the indicator system for op-erating and closing doors is to be independent of the powersupply for operating and closing the door and is to be provided

with a back-up power supply from the emergency source ofpower or other secure power supply. The sensor of indicatorsystem is to be protected from water, ice formation, and me-chanical damages.Note: The indicator system is considered designed onthe fail - safe principal when:

1) The indication panel is provided with:- a power failure alarm- an earth failure alarm- a lamp test- separate indication for door closed,

door locked, door not closed and doornot locked.

2) Limit switches electrically closed when thedoor is closed (when more limit switchesare provided they may be connected in se-ries).

3) Limit switches electrically closed whensecuring arrangements are in place (whenmore limit switches are provided they maybe connected in series).

4) Two electrical circuits (also in one multi-core cable), one for the indication of doorclosed / not closed and the other for doorlocked / not locked.

5) In case of dislocation of limit switches, in-dication to show : not closed / not locked /securing arrangement not in place - as ap-propriate.

7.4.1.6.6 The indication panel on the navigation bridge isto be equipped with a mode selection function "harbour/seavoyage", so arranged that audible alarm is given on the navi-gation bridge if the vessel leaves harbour with the bow door orinner door not closed or with any of the securing devices notin the correct position.

7.4.1.6.7 A water leakage detection system with audiblealarm and television surveillance is to be arranged to providean indication to the navigation bridge and to the engine controlroom of leakage through the inner door.

See Note in item 7.4.1.6.5.

7.4.1.6.8 Between the bow door and the inner door a tele-vision surveillance system is to be fitted with a monitor on thenavigation bridge and in the engine control room. The systemmust monitor the position of doors and a sufficient number oftheir securing devices. Special consideration is to be given forlighting and contrasting colour of objects under surveillance.


7.4.1.6.9 A drainage system is to be arranged in the areabetween bow door and ramp, as well as in the area betweenthe ramp and inner door where fitted. The system is to beequipped with an audible alarm function to the navigationbridge for water level in these areas exceeding 0,5 [m] abovethe car deck level.


7.4.1.6.10 For ro-ro passenger ships on international voy-ages, the special category spaces and ro-ro spaces are to becontinuously patrolled or monitored by effective means, suchas television surveillance, so that any movement of vehicles inadverse weather conditions or unauthorised access by passen-gers thereto, can be detected whilst the ship is underway.


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7.4.1.7 Operating and maintenance manual

7.4.1.7.1 An operating and maintenance manual for thebow door and inner door is to be provided on board and is tocontain necessary information on:

- main particulars and design drawings;special safety precautionsdetails of vesselequipment and design loading (for ramps)key plan of equipment (doors and ramps)manufacturer’s recommended testing forequipmentdescription of equipment forbow doorsinner bow doorsbow ramp/doorsside doorsstern doorscentral power packbridge panelengine control room panel

- service conditionslimiting heel and trim of ship for load-ing/unloadinglimiting heel and trim for door operationsdoors/ramps operating instructionsdoors/ramps emergency operating instruc-tions

- maintenanceschedule and extent of maintenancetrouble shooting and acceptable clearancesmanufacturer’s maintenance procedures

- register of inspections and repairs, includ-ing inspection of locking, securing andsupporting devices, and repairs and renew-als.

This manual is to be submitted to the Registerfor approval that the above mentioned items are contained inthe OMM and that the maintenance part includes the necessaryinformation with regard to inspections, trouble-shooting andacceptance / rejection criteria.

Note: It is recommended that recorded inspections ofthe door supporting and securing devices be carried out by theship’s staff at monthly intervals or following incidents thatcould result in damage, including heavy weather or contact inthe region of the shell doors.

Any damages recorded during inspections of thedoor supporting and securing devices, carried out by the ship'sstaff, are to be reported to the Register.

7.4.1.7.2 Documented operating procedures for closingand securing the bow door and inner door are to be kept onboard and posted at appropriate place.

7.4.2 Side shell doors and stern doors

7.4.2.1 General

7.4.2.1.1 These requirements are for the arrangement,strength and securing of side shell doors, abaft the collisionbulkhead, and stern doors leading to enclosed spaces.

The requirements apply to all ro-ro passengerships and ro-ro cargo ships engaged on international voyages

and also to ro-ro passenger ships and ro-ro cargo ships en-gaged only in domestic (non-international) voyages, exceptwhere specifically indicated otherwise herein.

The requirements are not applicable to highspeed, light displacement craft as defined in the IMO Code ofSafety for High Speed Craft.

7.4.2.1.2 Arrangement of doors

7.4.2.1.2.1 Stern doors for passenger vessels are to be situ-ated above the freeboard deck. Stern doors for Ro-Ro cargoships and side shell doors may be either below or above thefreeboard deck..

7.4.2.1.2.2 Side shell doors and stern doors are to be so fit-ted as to ensure tightness and structural integrity commensu-rate with their location and the surrounding structure.

7.4.2.1.2.3 Where the sill of any side shell door is below theuppermost load line, the arrangement is to be specially consid-ered.

7.4.2.1.2.4 Doors should preferably open outwards.

7.4.2.1.3 Definitions

7.4.2.1.3.1 For definitions see item 7.4.1.1.7.

7.4.2.2 Strength criteria

7.4.2.2.1 Primary structure and securing and sup-porting devices

7.4.2.2.1.1 Scantlings of the primary members, securing andsupporting devices of side shell doors and stern doors are to bedetermined to withstand the design loads defined in 7.4.2.3,using the following permissible stresses:

shear stress: τ = k

80 , [N/mm2]

bending stress: σ = k

120, [N/mm2]

equivalent stress: σc = 22 3τσ + = k

150 , [N/mm2]

where k is the material factor as given in Rules, Part 2 - Hull,1.4, but is not to be taken less than 0.72 unless a directstrength analysis with regard to relevant modes of failures iscarried out.

7.4.2.2.1.2 The buckling strength of primary members is tobe verified as being adequate.

7.4.2.2.1.3 For steel to steel bearings in securing and sup-porting devices, the nominal bearing pressure calculated bydividing the design force by the projected bearing area is notto exceed 0,8 σF , where σF is the yield stress of the bearingmaterial. For other bearing materials, the permissible bearingpressure is to be determined according to the manufacturer'sspecification.

7.4.2.2.1.4 The arrangement of securing and supporting de-vices is to be such that threaded bolts do not carry supportforces. The maximum tension in way of threads bolts not car-rying support forces is not to exceed 125/k [N/mm2], with kdefined in 7.4.2.2.1.1.


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7.4.2.2.1.5 The buckling strength of primary members is tobe verified as being adequate.

7.4.2.2.1.6 For steel to steel bearings in securing and sup-porting devices, the nominal bearing pressure calculated bydividing the design force by the projected bearing area is notto exceed 0.8 σF, where σF is the yield stress of the bearingmaterial. For other bearing materials, the permissible bearingpressure is to be determined according to the manufacturer'sspecification.

7.4.2.3 Design loads

7.4.2.3.1 The design forces, in [kN], considered for thescantlings of primary members, securing and supporting de-vices of side shell doors and stern doors are to be not less than:

7.4.2.3.1.1 Design forces for securing or supporting devicesof doors opening inwards:

external force: Fe = Ape + Fpinternal force: Fi = Fo + 10 W

7.4.2.3.1.2 Design forces for securing or supporting devicesof doors opening outwards:

external force: Fe = A⋅peinternal force: Fi = Fo + 10 W + Fp

7.4.2.3.1.3 Design forces for primary structural members:external force: Fe = A peinternal force: Fi = Fo + 10 Wwhichever is the greater,

where:A = area, in [m2], of the door opening,W = mass of the door, in [t],Fp = total packing force, in [kN], packing line

pressure is normally not to be taken lessthan 5 N/mm,

Fo = the greater of Fc and 5A, in [kN],Fc = accidental force, in [kN], due to loose of

cargo etc., to be uniformly distributedover the area A and not to be taken lessthan 300 kN. For small doors such asbunker doors and pilot doors, the valueof Fc may be appropriately reduced.However, the value of Fc may be takenas zero, provided an additional structuresuch as an inner ramp is fitted, which iscapable of protecting the door from ac-cidental forces due to loose cargoes.

pe = external design pressure, in [kN/m2],determined at the centre of gravity of thedoor opening and not taken less than:

pe = 10 ( T - ZG ) + 25, in [kN/mm2],for ZG < T

pe = 25 kN/mm2, for ZG > TNote:

The external pressure applied on stern doors is derivedfrom the formula considered in 7.4.1.3.1 for bow doors,assuming:

α = 0°β = 90°V = 2 knots

7.4.2.3.2 Moreover, for stern doors of ships fitted withbow doors, Pe is not to be taken less than:

Pe = 0,6 λ CH (0,8 + 0,6L0.5 ) 2

where:λ = coefficient depending on the area where

the ship is intended to be operated:= 1, for sea going ships, all navigation areas= 0,8,for ships operated in coastal waters,

navigation areas 5, 6, 7 and 8= 0,5, for ships operated in sheltered waters,

navigation areas 7 and 8.Navigation area, coastal waters and sheltered

waters, are defined in Rules, Part 1 - General requirements,Chapter 1 - General information, 4.2.

CH = 0.0125⋅L, for L < 80m= 1, for L ≥ 80m

L = ship's length, in [m], but need not be takengreater than 200 metres,

T = draught, in [m], at the highest subdivisionload line,

ZG = height of the centre of area of the door, in[m], above the baseline.

7.4.2.4 Scantlings of side shell doors and stern doors

7.4.2.4.1 General

7.4.2.4.1.1 The strength of side shell doors and stern doorsis to be commensurate with that of the surrounding structure.

7.4.2.4.1.2 Side shell doors and stern doors are to be ade-quately stiffened and means are to be provided to prevent anylateral or vertical movement of the doors when closed. Ade-quate strength is to be provided in the connections of the lift-ing/manoeuvring arms and hinges to the door structure and tothe ship's structure.

7.4.2.4.1.3 Where doors also serve as vehicle ramps, the de-sign of the hinges should take into account the ship angle oftrim and heel, which may result in uneven loading on thehinges.

7.4.2.4.1.4 Shell door openings are to have well-roundedcorners and adequate compensation is to be arranged with webframes at sides and stringers or equivalent above and below.

7.4.2.4.2 Plating and secondary stiffeners

7.4.2.4.2.1 The thickness of the door plating is not to be lessthan the required thickness for the side shell plating, using thedoor stiffener spacing, but in no case less than the minimumrequired thickness of shell plating.

Where doors serve as vehicle ramps, the platingthickness is to be not less than required for vehicle decks.

7.4.2.4.2.2 The section modulus of horizontal or verticalstiffeners is not to be less than that required for side framing.Consideration is to be given, where necessary, to differencesin fixity between ship's frames and door stiffeners.

Where doors serve as vehicle ramps, the stiff-ener scantlings are not to be less than required for vehicledecks.

7.4.2.4.3 Primary structure

7.4.2.4.3.1 The secondary stiffeners are to be supported byprimary members constituting the main stiffening of the door.


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7.4.2.4.3.2 The primary members and the hull structure inway are to have sufficient stiffness to ensure structural integ-rity of the boundary of the door.

7.4.2.4.3.3 Scantlings of the primary members are generallyto be supported by direct strength calculations in associationwith the design forces given in 7.4.2.3 and permissible stressesgiven in 7.4.2.2.1.1.

Normally, formulae for simple beam theory maybe applied to determine the bending stresses. Members are tobe considered to have simply supported end connections.

7.4.2.5 Securing and supporting of doors

7.4.2.5.1 General

7.4.2.5.1.1 Side shell doors and stern doors are to be fittedwith adequate means of securing and supporting so as to becommensurate with the strength and stiffness of the sur-rounding structure. The hull supporting structure in way of thedoors is to be suitable for the same design loads and designstresses as the securing and supporting devices.

Where packing is required, the packing materialis to be of a comparatively soft type, and the supporting forcesare to be carried by the steel structure only. Other types ofpacking may be considered.

Maximum design clearance between securingand supporting devices is not generally to exceed 3 mm.

A means is to be provided for mechanically fix-ing the door in the open position.

7.4.2.5.1.2 Only the active supporting and securing deviceshaving an effective stiffness in the relevant direction are to beincluded and considered to calculate the reaction forces actingon the devices. Small and/or flexible devices such as cleatsintended to provide local compression of the packing materialare not generally to be included in the calculations called forin 7.4.2.5.2.2. The number of securing and supporting devicesare generally to be the minimum practical whilst taking intoaccount the requirement for redundant provision given in7.4.2.5.2.3 and the available space for adequate support in thehull structure.

7.4.2.5.2 Scantlings

7.4.2.5.2.1 Securing and supporting devices are to be ade-quately designed so that they can withstand the reaction forceswithin the permissible stresses given in 7.4.2.2.1.1.

7.4.2.5.2.2 The distribution of the reaction forces acting onthe securing devices and supporting devices may require to besupported by direct calculations taking into account the flexi-bility of the hull structure and the actual position of the sup-ports.

7.4.2.5.2.3 The arrangement of securing devices and sup-porting devices in way of these securing devices is to be de-signed with redundancy so that in the event of failure of anysingle securing or supporting device the remaining devices arecapable to withstand the reaction forces without exceeding bymore than 20 per cent the permissible stresses as given in7.4.2.2.1.1.

7.4.2.5.2.4 All load transmitting elements in the design loadpath, from the door through securing and supporting devicesinto the ship's structure, including welded connections, are to

be to the same strength standard as required for the securingand supporting devices. These elements include pins, supportbrackets and back-up brackets.

7.4.2.6 Securing and locking arrangement

7.4.2.6.1 Systems for operation

7.4.2.6.1.1 Securing devices are to be simple to operate andeasily accessible. Securing devices are to be equipped withmechanical locking arrangement (self locking or separate ar-rangement), or are to be of the gravity type. The opening andclosing systems as well as securing and locking devices are tobe interlocked in such a way that they can only operate in theproper sequence.

7.4.2.6.1.2 Doors which are located partly or totally belowthe freeboard deck with a clear opening area greater than 6 m2

are to be provided with an arrangement for remote control,from a position above the freeboard deck, of:

- the closing and opening of the doors- associated securing and locking devices.For doors which are required to be equipped

with a remote control arrangement, indication of theopen/closed position of the door and the securing and lockingdevice is to be provided at the remote control stations. The op-erating panels for operation of doors are to be inaccessible tounauthorised persons. A notice plate, giving instructions to theeffect that all securing devices are to be closed and locked be-fore leaving harbour, is to be placed at each operating paneland is to be supplemented by warning indicator lights.

7.4.2.6.1.3 Where hydraulic securing devices are applied,the system is to be mechanically lockable in closed position.This means that, in the event of loss of the hydraulic fluid, thesecuring devices remain locked.

The hydraulic system for securing and lockingdevices is to be isolated from other hydraulic circuits, whenclosed position.

7.4.2.6.2 Systems for indication/monitoring

7.4.2.6.2.1 The following requirements apply to doors in theboundary of special category spaces or ro-ro spaces, see theRules, Part 17 - Fire protection, 2.2, through which suchspaces may be flooded.

For cargo ships, where no part of the door isbelow the uppermost waterline and the area of the door open-ing is not greater than 6 m2, then the requirements of this sec-tion need not be applied.

7.4.2.6.2.2 Separate indicator lights and audible alarms areto be provided on the navigation bridge and on each operatingpanel to indicate that the doors are closed and that their se-curing and locking devices are properly positioned.

The indication panel is to be provided with alamp test function. It is not to be possible to turn off the indi-cator light.

7.4.2.6.2.3 The indicator system is to be designed on the failsafe principle and is to show by visual alarms if the door is notfully closed and not fully locked and by audible alarms if se-curing devices become open or locking devices become unse-cured. The power supply for the indicator system is to be in-dependent of the power supply for operating and closing the


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doors and is to be provided with a backup power supply fromthe emergency source of power or secure power supply.

See 7.4.1.6.5 for fail safe principal design.The sensors of the indicator system are to be

protected from water, ice formation and mechanical damages.

7.4.2.6.2.4 The indication panel on the navigation bridge isto be equipped with a mode selection function "harbour/seavoyage", so arranged that audible alarm is given on the navi-gation bridge if the vessel leaves harbour with any side shellor stern door not closed or with any of the securing devicesnot in the correct position.

7.4.2.6.2.5 For passenger ships, a water leakage detectionsystem with audible alarm and television surveillance is to bearranged to provide an indication to the navigation bridge andto the engine control room of any leakage through the doors.

For cargo ships, a water leakage detection sys-tem with audible alarm is to be arranged to provide an indica-tion to the navigation bridge.

7.4.2.6.2.6 For ro-ro passenger ships, on international voy-ages, the special category spaces and ro-ro spaces are to becontinuously patrolled or monitored by effective means, suchas television surveillance, so that any movement of vehicles inadverse weather conditions and unauthorised access by pas-sengers thereto, can be detected whilst the ship is underway.

7.4.2.7 Operating and maintenance manual

7.4.2.7.1 An operating and maintenance manual for theside shell and stern doors is to be provided on board and con-tain necessary information (see 7.4.1.7.1).

This manual has to be submitted for approval tothe Register that the above mentioned items are contained inthe OMM and that the maintenance part includes the necessaryinformation with regard to inspections, trouble-shooting andacceptance / rejection criteria.

Note:It is recommended that recorded inspections of the doorsupporting and securing devices be carried out by theship's staff at monthly intervals or following incidents thatcould result in damage, including heavy weather or con-tact in the region of side shell and stern doors. Any dam-age recorded during such inspections is to be reported tothe Register.

7.4.2.7.2 Documented operating procedures for closingand securing side shell and stern doors are to be kept on boardand posted at the appropriate places.

7.5 SUPERSTRUCTURES ANDDECKHOUSES

7.5.1 Construction, openings and closing appli-ances

7.5.1.1 Openings in the freeboard deck other than thosedefined in 7.3, 7.6 to 7.11 are to be protected by the enclosedsuperstructure or enclosed deckhouse.

The similar openings in the deck of enclosed su-perstructure or enclosed deckhouse are to be protected by en-closed deckhouse of the second tier.

7.5.1.2 Superstructures and deckhouses are consideredenclosed if:

- their construction complies with the Rules,Part 2 - Hull, 13.

- all access openings comply with the re-quirements of 7.5.2 and 7.7;

- all other openings in their outside contourcomply with requirements of 7.2 to 7.4 and7.7 to 7.10.

7.5.2 Doors in enclosed superstructures and en-closed deckhouses

7.5.2.1 All access openings in the end bulkheads of en-closed superstructures and outside bulkheads of encloseddeckhouses are to be fitted with doors.

7.5.2.2 The height of the sills to access openings speci-fied in 7.5.2.1 is to be at least 380 mm. However, the bridgeor poop is to not be regarded as enclosed unless access is pro-vided for the crew to machinery and other working spaces in-side these superstructures from any place in the uppermostcontinuous open deck or above it by alternative means whichare available at all times when bulkhead openings are closed,the height of the sills of the openings in the bulkheads of suchbridge or poop is to be at least 600 mm in position 1 and atleast 380 mm in position 2.

7.5.2.3 The doors are to be permanently and stronglyattached to the bulkhead and fitted with clamping devices orother equivalent means for expeditiously opening, closing andsecuring them weathertight; such devices are to be so ar-ranged that they can be operated from both sides of the bulk-head.

The doors are to be opening outside, opening ofdoors inside the superstructure or deckhouse space is to bespecially considered by the Register in each case.

7.5.2.4 The doors are to be weathertight when secured.The tightness is to be ensured by a rubber or other suitablegasket.

7.5.2.5 The doors are to be made of steel or other mate-rial approved by the Register.

The strength of the door is to be of equivalentstrength to the unpierced bulkhead.

7.6 MACHINERY CASINGS

7.6.1 Machinery space openings in positions 1 and 2are to be efficiently enclosed by casings of ample strengthraised above the decks as far as is reasonable and practicable,and terminated themselves by a deck, or covers if a skylight isin question. The construction of the casings shall meet theRules, Part 2 - Hull, 13.

7.6.2 Casings are to be made weathertight.

7.6.3 Casings are to be made of steel or other materi-als approved by Register.


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7.6.4 The access openings in the casings are to be fit-ted with permanently attached doors which shall comply withthe requirements of 7.5.2.3-7.5.2.5. The height of the sills is tobe at least 600 mm in position 1 and at least 380 mm in posi-tion 2.

7.6.5 In Type "A" ships and also in Type "B" shipswhich are permitted to have the tabular freeboard less thanthat prescribed by ICLL, 1966, the engine and boiler casingsare to be protected by enclosed poop or bridge of at least stan-dard height, or by a deckhouse of equal height and equivalentstrength. However, engine and boiler casings may be exposedif there are no openings giving direct access from the free-board deck to the machinery space. A door complying withrequirements of 7.5.2.3 to 7.5.2.5 may, however, be permittedin the machinery casing provided that it leads to a space orpassageway which is as strongly constructed as the casing andis separated form the stairway to the engine and boiler roomby a second similar door. The opening for the outside door isto be provided with a sill at least 600 mm in height, and thatfor the inside door with a sill of at least 230 mm in height.

7.6.6 In supply vessels the doors in the casings givingaccess to the engine or boiler rooms are to be located, wherepossible, inside the enclosed superstructure or deckhouse.

The door in the casing for access to the engine orboiler room may be fitted directly on the open cargo providedthat, in addition to the first outside door, the second insidedoor is fitted; in this case, the outside and inside doors shallsatisfy the requirements of 7.5.2.3 to 7.5.2.5, the height of theoutside door sill is to be at least 600 mm, and of the insidedoor sill, at least 230 mm.

7.7 COMPANION HATCHES,SKYLIGHTS AND VENTILATING

TRUNKS

7.7.1 Deck openings in positions 1 and 2 intended forstairways to the ship's spaces located below as well as lightand air openings to these spaces are to be protected by strongcompanion hatches, skylights and ventilating trunks.

Where the openings intended for stairways to theship's spaces located below are protected by superstructures ordeckhouse instead of companion hatches, these superstructuresor deckhouse shall comply with the requirements of 7.5.

7.7.2 The height of coamings of companion hatches,skylights and ventilating trunks is to be at least 600 mm in po-sition 1 and at least 450 mm in position 2.

The construction of coamings shall comply withrequirements of the Rules, Part 2 - Hull, 2.6.

7.7.3 All companion hatches, skylights and ventilatingtrunks are to be provided with covers made of steel or someother approved material and permanently attached to thecoamings.

Where the covers are made of steel, the thick-ness of their plating is to be equal to at least 0,01 times thespacing of the stiffeners but no less than 6 mm. The minimumspecified thickness of 6 mm may be reduced if the cover wasformed by pressing, as shown in Figure 7.7.3 and in Table7.7.3-1.

Figure 7.7.3

Table 7.7.3-1

CasingDimensionsl x b, [mm]

CoverMaterial

Height ofPress

h, [mm]

MinimumThicknesss, [mm]

steel450 x 600 light alloy 25 4

steel600 x 600 light alloy 28 4

steel 4700 x 700 light alloy 40 6



1000 x 1400 steel 90 5

On small vessels with a deck plating less than 6mm in thickness, the thickness of the cover may be equal tothe thickness of the deck, but not less than 4 mm.

7.7.4 Covers of companion hatches, skylights andventilating trunks are to have securing devices workable atleast from outside of the hatch. However, where the hatchesare used as emergency exits in addition to their primary appli-cation, the securing devices are to be capable of being oper-ated from each side of the cover.

When secured, the covers are to be weathertight.The tightness is to be provided by a rubber or other suitablegasket.

7.7.5 The glass for windows in the covers of skylightsis to be hardened and at least 6 mm thick if the inner diameteris 150 mm and below, and at least 12 mm with the inner di-ameter of 450 mm.

For intermediate inner diameters, the thicknessof glass is to be determined by liner interpolation. However,where wire-reinforced glass is used, its thickness may be 5mm, and the requirement relating to its hardening is not to beapplicable.

Glass is to be efficiently attached to the coversby means of a frame and have on its contour a weathertightgasket of rubber or other equivalent material.

Windows in the covers of skylights fitted in ma-chinery spaces shall comply with the requirements of theRules, Part 17 - Fire protection, 2.1.

7.7.6 Each window or group of adjacent windows is tobe provided with portable shields of the same material as thecover being at least 3 mm in thickness and capable of beingefficiently fastened outside the cover by means of ear-nuts;

l +l1

h

s


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such portable shields are to be stowed adjacent to the sky-lights.

7.8 VENTILATORS

7.8.1 Ventilators to spaces below freeboard deck ordeck of enclosed superstructures and deckhouses are to be fit-ted with coamings efficiently connected to the deck. Thecoamings of ventilators are to be at least 900 mm in height inposition 1 and at least 760 mm in position 2.

The thickness of the coaming plates is to be 7,5mm where the clear opening sectional area of the ventilatorcoamings is 300 cm2 or less, and 10 mm where the clearopening sectional area exceeds 1600 cm2. Intermediate valuesare to be determined by direct interpolation. A thickness of 6mm is generally to be sufficient within not permanently closedsuperstructures.

7.8.2 Ventilators in position 1 the coamings of whichextend to more than 4500 mm above the deck and in position2 the coamings of which extend to more than 2300 mm abovethe deck need not be fitted with closing appliances. In all othercases, each ventilator is to be fitted with a strong cover madeof steel or other material approved by the Register.

In ships of less than 100 m in length, the coversare to be permanently attached; in ships of 100 mm in lengthand over they may be conveniently stowed near the ventilatorsto which they are to be fitted.

7.8.3 When secured, the covers of ventilators are to beweathertight. The tightness is to be provided by a rubber orother suitable gasket.

7.8.4 In supply vessels, in order to minimise the pos-sibility of flooding of the spaces situated below, the ventilatorsare to be positioned in the protected locations where the prob-ability of their damage by cargo is excluded during cargo han-dling operations. Particular attention is to be given to the ar-rangement of ventilators of the engine and boiler rooms forwhich the location is preferable above the deck level of thefirst tier of superstructures or deckhouses.

7.8.5 The ventilation of machinery spaces shall be ac-cording to the principles laid down in SOLAS Regulation II-1/35 and supplied through suitably protected openings ar-ranged in such a way that they can be used in all weather con-ditions, taking into account Reg.17(3) and Reg.19 of the 1966Load Line Convention as amended by the Protocol of 1988.

The machinery spaces are those defined in SO-LAS Regulation II-1/3.16.

7.9 MANHOLES

7.9.1 Covers of manholes are to be made of steel orother approved material.

Thickness of the covers is not to be less than thatof the plating on which they are fitted. In some cases it may bepermitted to decrease the thickness of the covers provided thethickness of plating is greater than 12 mm.

7.9.2 The covers of manholes are to be efficiently at-tached to the coaming or doubling ring by means of bolts orpins with nuts.

7.9.3 When secured, the covers are to be tight underinner pressure of water or other liquids, for which the tanksare intended, up to the top of the air pipe. The tightness is tobe provided by a rubber or other suitable gasket. The gasket isto be resistant to the liquid cargoes referred to above.

7.10 HATCHWAYS OF DRY CARGOHOLDS

7.10.1 General

7.10.1.1 The deck openings through which cargoes orship's stores are loaded and unloaded are to be protected bystrong hatchways. If these hatchways are situated in positions1 and 2 (see Section 7.1.4), the hatchway covers are to weath-ertight. The tightness is to be provided by one of the followingtwo methods:

.1 closed by portable covers and securedweathertight by tarpaulins and batteningdevices;

.2 by weathertight covers made of steel orother equivalent material fitted with rubberor other suitable gaskets and clamping de-vices.

7.10.1.2 The strength requirements are applicable tohatch covers and hatch coamings of stiffened plate construc-tion and its closing arrangements.

7.10.1.3 These requirements are applicable to hatch cov-ers and coamings made of steel. In case of alternative materi-als and innovative designs the approval is subject to specialconsideration of the Register.

7.10.1.4 These requirements don't apply to portable cov-ers secured weathertight by tarpaulins and battening devices,or pontoon covers, as defined in ICLL Regulation 15.

7.10.1.5 Hatchways on freeboard and superstructuredecks are to have coamings, the minimum height of whichabove the deck is to be as follows:

− in position 1: 600 mm− in position 2: 450 mm

7.10.1.6 The height of coamings of the hatchways speci-fied in 7.10.1.1.2 may be decreased in relation to that pre-scribed by 7.10.1.5 or the coamings may be omitted entirelywhere the efficiency of the cover tightness and securing meanswill satisfy the Register.

7.10.1.7 Where an increased freeboard is assigned, theheight of hatchway coamings according to 7.10.1.5 on the ac-tual freeboard deck may be as required for a superstructuredeck, provided the summer freeboard is such that the resultingdraught will not be greater than that corresponding to theminimum freeboard calculated from an assumed freeboarddeck situated at a distance equal to a standard superstructureheight hN below the actual freeboard deck.

7.10.1.8 Coamings are not to be required for hatchwaysbelow the freeboard deck or within weathertight closed super-structure unless they are required for the strength purposes.

7.10.1.9 Coamings which are 600 mm or more in heightare to be stiffened by a horizontal stiffener. Where the unsup-ported height of a coaming exceeds 1,2 m additional stiffeners


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are to be arranged. Additional stiffeners may be dispensedwith if this is justified by the ship's service and if sufficientstrength is verified (e.g. in case of container ships).

7.10.1.10 For hatch way coamings which are designed onthe basis of strength calculations as well as for hatch girders,cantilevers and pillars, see Part 2, Section 9.

For structural members welded to coamings andfor cutouts in the top of coaming sufficient fatigue strengthaccording to Part 2, Section 16 is to be verified.

7.10.1.11 Hatchway coamings are to be adequately sup-ported by stays.

7.10.1.12 Hatch coamings and supporting structures are tobe adequately stiffened to accommodate the loading fromhatch covers, in longitudinal, transverse and vertical direc-tions.

Coaming stays are to be supported by appropri-ate substructures.

Under deck structures are to be designed underconsideration of permissible stresses according to 7.10.3.1.

7.10.1.13 Adequate safety against buckling according toSection 4, 4.6 is to be proved for longitudinal coamings whichare part of the longitudinal hull structure.

7.10.1.14 The connection of the coamings to the deck atthe hatchway corners is to be carried out with special care. Forbulk carriers, see also Part 2, Section 17, 17.2.8.

7.10.1.15 For rounding of hatchway corners, see also Part2, Section 6, 6.1.3.

7.10.1.16 For application of the corrosion margin requiredby Regulation 16 (5)(d) of the ICLL, 1996 (Res. MSC.143(77), see 7.10.7, 7.10.8.6 and IACS Unified InterpretationLL 70.

7.10.2 Evaluation of scantlings of hatch covers andhatch coamings and closing arrangements ofcargo holds of ships

7.10.2.1 Application

These requirements apply to all ships exceptbulk carriers, ore carriers and combination carriers, as definedin the Rules, Part 1 – General Requirements, Chapter 1 –General Information, 4.2.5.5, and are for all cargo hatch cov-ers and coamings on exposed decks.

For evaluation of scantling of hatch covers andhatch coamings of cargo holds of bulk carriers, ore carriersand combination carriers, see 7.10.8.

These requirements apply for ships contractedfor construction on or after 1 July 2012. These requirementsare in addition to the requirements of the ICLL.

The “contracted for construction” date means thedate on which the contract to build the vessel is signed be-tween the prospective owner and the shipbuilder.

7.10.2.2 Definition

ICLL Where ICLL is referred to in the text, this is tobe taken as the International Convention on Load Lines, 1966as amended by the 1988 protocol, as amended in 2003.

7.10.2.2.1 Hatch cover types

7.10.2.2.1.1 Single skin cover

A hatch cover made of steel or equivalent mate-rial that is designed to comply with ICLL Regulation 16. Thecover has continuous top and side plating, but is open under-neath with the stiffening structure exposed. The cover isweathertight and fitted with gaskets and clamping devices un-less such fittings are specifically excluded.

7.10.2.2.1.2 Double skin cover

A hatch cover as above but with continuousbottom plating such that all the stiffening structure and inter-nals are protected from the environment.

7.10.2.2.1.3 Pontoon type cover

A special type of portable cover, secured weath-ertight by tarpaulins and battening devices. Such covers are tobe designed in accordance with ICLL Regulation 15 and arenot covered by these requirements.

Clarification note:

Modern hatch cover designs of lift-away-coversare in many cases called pontoon covers. This definition doesnot fit to the definition above. Modern lift-away hatch coverdesigns should belong to one of the two categories single skincovers or double skin cover.

7.10.2.2.2 Positions

The hatchways are classified according to theirposition as follows:

Position 1 Upon exposed freeboard and raised quarter-decks, and upon exposed superstructure deckssituated forward of a point located a quarter ofship’s length from forward perpendicular.

Position 2 Upon exposed superstructure decks situatedabaft a quarter of the ship’s length from the for-ward perpendicular and located at least onestandard height of the superstructure above thefreeboard deck.Upon exposed superstructure decks situatedforward of a point located a quarter of the ship’slength from the forward perpendicular and lo-cated at least two standard height of the super-structure above the freeboard deck.

7.10.2.3 Material

Hatch covers and coamings are to be made ofmaterial in accordance with the definitions of the Rules, Part 2– Hull, 1.4.2. A material class I is to be applied for hatch cov-ers.

7.10.2.4 General requirements

Primary supporting members and secondarystiffeners of hatch covers are to be continuous over the breadthand length of hatch covers, as far as practical. When this isimpractical, sniped end connections are not to be used and ap-


2013

propriate arrangements are to be adopted to provide sufficientload carrying capacity.

The spacing of primary supporting membersparallel to the direction of secondary stiffeners is not to exceed1/3 of the span of primary supporting members. Whenstrength calculation is carried out by FE analysis using planestrain or shell elements, this requirement can be waived.

Secondary stiffeners of hatch coamings are to becontinuous over the breadth and length of hatch coamings.

7.10.2.5 Net scantling approach

Unless otherwise quoted, the thicknesses t of thefollowing sections are net thicknesses.

The net thicknesses are the member thicknessesnecessary to obtain the minimum net scantlings required by7.10.3 and 7.10.5.

The required gross thicknesses are obtained byadding corrosion additions, tS, given in Table 7.10.7.1 in7.10.7.1.

Strength calculations using beam theory, grillageanalysis or FEM are to be performed with net scantlings.

7.10.2.6 Hatch cover and coaming load model

Structural assessment of hatch covers and hatchcoamings is to be carried out using the design loads, defined inthis chapter.

DefinitionsL = length of ship, in [m], as defined in

1.2.2.1LLL = length of ship, in [m], as defined in ICLL

Regulation 3x = longitudinal co-ordinate of mid point of

assessed structural member measuredfrom aft end of length L or LLL, as appli-cable

dfb = draught, in [m], corresponding to the as-signed summer load line

hN = standard superstructure height, in [m]

= LLL01,005,1 + , 3,28,1 ≤≤ Nh

7.10.2.6.1 Vertical weather design load

The pressure pH, in [kN/m²], on the hatch coverpanels is given by ICLL. This may be taken from Table7.10.2.6.1. The vertical weather design load needs not to becombined with cargo loads according to 7.10.2.6.3 and7.10.2.6.4.

In Fig.7.10.2.6.1-1 the positions 1 and 2 are il-lustrated for an example ship.

Where an increased freeboard is assigned, thedesign load for hatch covers according to Tab. 7.10.2.6.1 onthe actual freeboard deck may be as required for a superstruc-ture deck, provided the summer freeboard is such that the re-sulting draught will not be greater than that corresponding tothe minimum freeboard calculated from an assumed freeboarddeck situated at a distance at least equal to the standard super-structure height hN below the actual freeboard deck, seeFig.7.10.2.6.1-2.


2013

Table 7.10.2.6.1 Design load pH of weather deck hatches

Design load pH [kN/m2]

Position75,0≤

LLLx 0,175,0 ≤<

LLLx

for 24 m ≤ LLL ≤ 100 m

on freeboard deck

( )

+⋅−⋅+⋅⋅ 9571,12828,4

7681,9

LLLL

LL LLxL

( )1165,17681,9

+⋅⋅ LLL upon exposed superstructure decks located at least one superstructure standardheight above the freeboard deck

( )1165,17681,9

+⋅⋅ LLL

for LLL > 100 m

on freeboard deck for type B ships according to ICLL

( )

+⋅−⋅+⋅⋅ 22,10222,004,30296,081,9 11 L

LxLLL

on freeboard deck for ships with less freeboard than type B according to ICLL

( )

+⋅−⋅−⋅⋅ 89,91089,052,81452,081,9 11 L

LxLLL

L1 = LLL but not more than 340 m

1

5,381,9 ⋅

upon exposed superstructure decks located at least one superstructure standardheight above the freeboard deck

5,381,9 ⋅

for 24 m ≤ LLL ≤ 100 m

( )6,871,17681,9

+⋅ LLL

for LLL > 100 m

1,281,9 ⋅

2

upon exposed superstructure decks located at least one superstructure standard height above the lowest Position 2deck

1,281,9 ⋅


2013

Figure 7.10.2.6.1- 1 Positions 1 and 2

Figure 7.10.2.6.1- 2 Positions 1 and 2 for an increased freeboard

Length LLL

0,25 LLL

22**2**

22**

2 1*

2**2**

2

* reduced load upon exposed superstructure decks located at least one superstructure standard height above thefreeboard deck

** reduced load upon exposed superstructure decks of vessels with LLL > 100 m located at least one superstruc-ture standard height above the lowest Position 2 deck

Actual Freeboard DeckAssumed Freeboard Deck ≥ hN

dfb

Length LLL

0,25 LLL

122**

1*2

1 1

2**2**

1*

* reduced load upon exposed superstructure decks located at least one superstructure standard height above thefreeboard deck

** reduced load upon exposed superstructure decks of vessels with LLL > 100 m located at least one superstructurestandard height above the lowest Position 2 deck

Freeboard Deck

dfb


2013

7.10.2.6.2 Horizontal weather design load

The horizontal weather design load, in [kN/m²],for determining the scantlings of outer edge girders (skirtplates) of weather deck hatch covers and of hatch coamings is:

( )zfcbcap LA −⋅⋅⋅⋅=

f = 1,425

+L , for L < 90 m

=51

1003007510

,L,

−

− , for m300Lm90 <≤

= 10,75, for m350Lm300 <≤

=51

1503507510

,L,

−

− , for m500Lm350 ≤≤

cL =90L , for L < 90 m

= 1, for L ≥ 90 m

a =12

20 1L+ , for unprotected front coamings and

hatch cover skirt plates

a =12

10 1L+ , for unprotected front coamings and

hatch cover skirt plates, where the distance fromthe actual freeboard deck to the summer loadline exceeds the minimum non-corrected tabularfreeboard according to ICLL by at least onestandard superstructure height hN

a =15

5 1L+ , for side and protected front coamings

and hatch cover skirt plates

a =L'xL

⋅−+ 8100

7 1 , for aft ends of coamings and

aft hatch cover skirt plates abaft amidships

a =L'xL

⋅−+ 4100

5 1 , for aft ends of coamings and

aft hatch cover skirt plates forward of amidshipsL1 = L, need not be taken greater than 300 m

b =2

20

45001

+

−+

,C

,L'x

,B

, for 450,L'x

<

=2

20

4505101

+

−⋅+

,C

,L'x

,,B

, for 450,L'x

≥

8,06,0 ≤≤ BC ,when determining scantlings of aftends of coamings and aft hatch cover skirt platesforward of amidships, CB need not be taken lessthan 0,8.

x’ = distance, in [m], between the transverse coamingor hatch cover skirt plate considered and aft endof the length L. When determining side coam-ings or side hatch cover skirt plates, the side is to

be subdivided into parts of approximately equallength, not exceeding 0,15⋅L each, and x’ is to betaken as the distance between aft end of thelength L and the centre of each part considered.

z = vertical distance, in [m], from the summer loadline to the midpoint of stiffener span, or to themiddle of the plate field

''7,03,0

Bbc ⋅+=

b' = breadth of coaming in m at the position consid-ered

B' = actual maximum breadth of ship , in [m], on theexposed weather deck at the position considered.

b'/B' is not to be taken less than 0,25.The design load pA is not to be taken less than

the minimum values given in Table 7.10.2.6.2.

Table 7.10.2.6.2 Minimum design load pAmin

PAmin , in [kN/m²], forL

unprotected fronts elsewhere

50≤ 30 15

50>

250< 1025 L

+20

5,12 L+

250≥ 50 25

7.10.2.6.3 Cargo loads

7.10.2.6.3.1 Distributed loads

The load on hatch covers due to cargo loads pL,in [kN/m²], resulting from heave and pitch is to be determinedaccording to the following formula:

( )VCL app += 1

pC = uniform cargo load, in [kN/m²],

av = acceleration addition as follows:mFaV ⋅=

Lv

,F 0110 ⋅=

m = ( )Lxmm 15 00 −− , for 200 ,

Lx

≤≤ ,

= 1.0, for 7020 ,Lx, ≤< ,

=

−

++ 70

301

1 0 ,Lx

,m , for 0170 ,

Lx, ≤< ,

m0 = F+5,1 ,

v0 = max. speed at summer load line draught, v0 is notto be taken less than L , in [kn].


2013

7.10.2.6.3.2 Point loads

The loads due to single forces P, in [kN], re-sulting from heave and pitch (e.g. in case of containers) are tobe determined as follows:

( )VS aPP += 1 ,

PS = single force, in [kN].

7.10.2.6.4 Container loads

Where containers are stowed on hatch covers thefollowing loads, in [kN], due to heave, pitch, and the ship'srolling motion are to be considered, see also Fig 7.10.2.4.

( )

−⋅+⋅=

bh

aMA mVz 42,045,01

281,9

( )

+⋅+⋅=

bh

aMB mVz 42,045,01

281,9

MBy ⋅= 4,2

av = acceleration addition according to 7.10.2.6.3.1,M = maximum designed mass of container stack, in [t],hm = designed height of centre of gravity of stack above

hatch cover supports, in [m],b = distance between foot points, in [m],Az,Bz =support forces in z-direction at the forward and aft

stack corners,By = support force in y-direction at the forward and aft

stack corners.Note:

For M and hm it is recommended to apply thosevalues, which are used for the calculations of cargo securing(container lashing). If different assumptions are made for Mand hm, the designer has to verify that, in the calculationmodel, the hatch cover structure is not loaded less than bythose values recommended.

When strength of the hatch cover structure is as-sessed by FE analysis according to 7.10.3.5.2 using shell orplane strain elements, hm may be taken as the designed heightof centre of gravity of stack above the hatch cover top plate.

Values of M and hm applied for the assessmentof hatch cover strength are to be shown in the drawings of thehatch covers.

��

�

��

��

��

Figure 7.10.2.6.4 Forces due to container loads

In case of container stacks secured to lashingbridges or carried in cell guides the forces acting on the hatchcover may be specially considered.

Alternatively, container loads may be appliedbased on accelerations calculated by an individual accelerationanalysis for the used lashing system. The individual accelera-tion analysis shall be carried out by the Register.

7.10.2.6.4.1 Load cases with partial loading

The load cases 7.10.2.6.3 and 7.10.2.6.4 are alsoto be considered for partial non homogeneous loading whichmay occur in practice, e.g. where specified container stackplaces are empty.

The load case partial loading of container hatchcovers can be evaluated using a simplified approach, wherethe hatch cover is loaded without the outermost stacks, seeFig.7.10.2.6.4.1.

Figure 7.10.2.6.4.1 Partial loading of a container hatchcover

7.10.2.6.5 Loads due to elastic deformations of theship's hull

Hatch covers, which in addition to the loads ac-cording to 7.10.2.6.1 to 7.10.2.6.4 are loaded in the ship'stransverse direction by forces due to elastic deformations ofthe ship's hull, are to be designed such that the sum of stressesdoes not exceed the permissible values given in 7.10.3.1.1.

7.10.3 Hatch cover strength criteria

7.10.3.1 Permissible stresses and deflections

7.10.3.1.1 Stresses

The equivalent stress σv in steel hatch coverstructures related to the net thickness shall not exceed 0,8·σF,where σF is the minimum yield stress, in [N/mm2], of the ma-terial. For design loads according to 7.10.2.6.2 to 7.10.2.6.5,the equivalent stress σv related to the net thickness shall notexceed 0,9 ·σF when the stresses are assessed by means ofFEM using plane stress or shell elements.


2013

For steels with a minimum yield stress of morethan 355 N/mm2, the value of σF to be applied throughout thisrequirement is subject to the Register but is not to be morethan the minimum yield stress of the material.

For beam element calculations and grillageanalysis, the equivalent stress may be taken as follows:

22 3τσσ +=V , in [N/mm²],

σ = normal stress, in [N/mm²],τ = shear stress, in [N/mm²].For FEM calculations, the equivalent stress may

be taken as follows:22

yyx2

xV 3τσσσσσ ++⋅−= , in [N/mm²]

σx = normal stress, in [N/mm²], in x-direction,σy = normal stress, in [N/mm²], in y-direction,τ = shear stress, in [N/mm²], in the x-y plane.

Indices x and y are coordinates of a two-dimensional Cartesian system in the plane of the consideredstructural element.

In case of FEM calculations using shell or planestrain elements, the stresses are to be read from the centre ofthe individual element. Where shell elements are used, thestresses are to be evaluated at the mid plane of the element.

Stress concentrations are to be assessed to thesatisfaction of the Register.

7.10.3.1.2 Deflection

The vertical deflection of primary supportingmembers due to the vertical weather design load according to7.10.2.6.1 is to be not more than 0,0056⋅lg where lg is thegreatest span of primary supporting members.Note:

Where hatch covers are arranged for carryingcontainers and mixed stowage is allowed, i.e., a 40'-containerstowed on top of two 20'-containers, particular attentionshould be paid to the deflections of hatch covers. Further thepossible contact of deflected hatch covers with in hold cargohas to be observed.

7.10.3.2 Local net plate thickness

The local net plate thickness t, in [mm], of thehatch cover top plating is not to be less than:

Fp

psFtσ⋅

⋅⋅=95,0

8,15

and to be not less than 1% of the spacing of the stiffener or 6mm if that be greater.

Fp = factor for combined membrane and bending re-sponse,

= 1,5 in general,

=aσ

σ⋅9,1 , for 8,0≥

aσσ for the attached plate flange

of primary supporting members,

s = stiffener spacing, in [m],p = pressure pH and pL, in [kN/m2], as defined in

7.10.2.6,

σ = normal stress, in [N/mm2], of hatch cover topplating,

σa = Fσ⋅8,0 , in [N/mm2].

For flange plates under compression sufficientbuckling strength according to 7.10.3.6 is to be demonstrated.

Note:The normal stress σ of the hatch cover plating

may be determined in a distance s from webs of adjacent pri-mary supporting members perpendicular to secondary stiffen-ers and in a distance s/2 from the web of an adjacent primarysupporting member parallel to secondary stiffeners, refer toFig 7.10.3.2. The greater of both stresses is to be taken. Forthe distribution of normal stress σ between two parallel gird-ers, refer to 7.10.3.6.3.2.

Figure 7.10.3.2 Determination of normal stress of thehatch cover plating

7.10.3.2.1 Local net plate thickness of hatch covers forwheel loading

The local net plate thickness of hatch covers forwheel loading have to be derived from the Rules, Part 2 –Hull, Section 6.

7.10.3.2.2 Lower plating of double skin hatch coversand box girders

The thickness to fulfill the strength requirementsis to be obtained from the calculation according to 7.10.3.5under consideration of permissible stresses according to7.10.3.1.1.

The net thickness must not be less than thelarger of the following values when the lower plating is takeninto account as a strength member of the hatch cover:

t = 6,5⋅s, in [mm],tmin = 5 mm,s = stiffener spacing, in [m].When the lower plating is not considered as a

strength member of the hatch cover, the thickness of the lowerplating should be determined according to the Rules, Part 2 -Hull.


2013

7.10.3.3 Net scantling of secondary stiffeners

The net section modulus W and net shear area Asof uniformly loaded hatch cover stiffeners constraint at bothends must not be less than:

plsWF

⋅⋅⋅= 2104σ

, in [cm3]

Fs

plsAσ

⋅⋅⋅=

10 , in [cm2]

l = secondary stiffener span, in [m], to betaken as the spacing, in [m], of primarysupporting members or the distance be-tween a primary supporting member andthe edge support, as applicable,

s = secondary stiffener spacing, in [m],p = pressure pH and pL, in [kN/m2], as de-

fined in 7.10.2.The net section modulus of the secondary stiff-

eners is to be determined based on an attached plate width as-sumed equal to the stiffener spacing.

For flat bar secondary stiffeners and bucklingstiffeners, the ratio h/tw is to be not greater than 15 k0.5,where:

h = height of the stiffener,tw = net thickness of the stiffener,k = 235/σF.Stiffeners parallel to primary supporting mem-

bers and arranged within the effective breadth according to7.10.3.5.1 must be continuous at crossing primary supportingmember and may be regarded for calculating the cross sec-tional properties of primary supporting members. It is to beverified that the combined stress of those stiffeners induced bythe bending of primary supporting members and lateral pres-sures does not exceed the permissible stresses according to7.10.3.1.1.

For hatch cover stiffeners under compressionsufficient safety against lateral and torsional buckling accord-ing 7.10.3.6.3 is to be verified.

For hatch covers subject to wheel loading stiff-ener scantlings are to be determined by direct calculations un-der consideration of the permissible stresses according to7.10.3.1.1 or are to be determined according to the Rules, Part2 – Hull, Section 6.

7.10.3.4 Net scantling of primary supporting members

7.10.3.4.1 Primary supporting members

Scantlings of primary supporting members areobtained from calculations according to 7.10.3.5 under con-sideration of permissible stresses according to 7.10.3.1.1.

For all components of primary supporting mem-bers sufficient safety against buckling must be verified ac-cording to 7.10.3.6. For biaxial compressed flange plates thisis to be verified within the effective widths according to7.10.3.6.3.2.

The net thickness, in [mm], of webs of primarysupporting members shall not be less than:

t = 6,5⋅s , in [mm],tmin = 5 mm,s = stiffener spacing, in [m].

7.10.3.4.2 Edge girders (Skirt plates)

Scantlings of edge girders are obtained from thecalculations according to 7.10.3.5 under consideration of per-missible stresses according to 7.10.3.1.1.

The net thickness, in [mm], of the outer edgegirders exposed to wash of sea shall not be less than the larg-est of the following values:

F

Apstσ⋅

⋅⋅=95,0

8,15

t = 8,5⋅s , in [mm],tmin = 5 mm,s = stiffener spacing, in [m],pA = horizontal pressure as defined in

7.10.2.6.2.The stiffness of edge girders is to be sufficient to

maintain adequate sealing pressure between securing devices.The moment of inertia, in [cm4], of edge girders is not to beless than:

46 SDsqI ⋅⋅=

q = packing line pressure, in [N/mm], mini-mum 5 N/mm,

sSD = spacing, in [m], of securing devices.

7.10.3.5 Strength calculations

Strength calculation for hatch covers may becarried out by either, using beam theory, grillage analysis orFEM.

7.10.3.5.1 Effective cross-sectional properties for calcu-lation by beam theory or grillage analysis

Cross-sectional properties are to be determinedconsidering the effective breadth. Cross sectional areas of sec-ondary stiffeners parallel to the primary supporting memberunder consideration within the effective breadth can be in-cluded, refer Fig.7.10.3.6.3.2-1.

The effective breadth of plating eM of primarysupporting members is to be determined according to Table7.10.3.5.1, considering the type of loading. Special calcula-tions may be required for determining the effective breadth ofone-sided or non-symmetrical flanges.

The effective cross sectional area of plates is notto be less than the cross sectional area of the face plate.

For flange plates under compression with secon-dary stiffeners perpendicular to the web of the primary sup-porting member, the effective width is to be determined ac-cording to 7.10.3.6.3.2.


2013

Table 7.10.3.5.1 Effective breadth eM of plating of primary supporting members

l/e 0 1 2 3 4 5 6 7 ≥ 8

em1 /e 0 0.36 0.64 0.82 0.91 0.96 0.98 1.00 1.00

em2 /e 0 0.20 0.37 0.52 0.65 0.75 0.84 0.89 0.90

em1 is to be applied where primary supporting members are loaded by uniformly distributed loads or else by not less than 6equally spaced single loads

em2 is to be applied where primary supporting members are loaded by 3 or less single loadsIntermediate values may be obtained by direct interpolation.

l = length of zero-points of bending moment curve:l = l0 for simply supported primary supporting membersl = 0,6 · l0 for primary supporting members with both ends constraint,where l0 is the unsupported length of the primary supporting member

e = width of plating supported, measured from centre to centre of the adjacent unsupported fields

7.10.3.5.2 General requirements for FEM calculations

For strength calculations of hatch covers bymeans of finite elements, the cover geometry shall be ideal-ized as realistically as possible. Element size must be appro-priate to account for effective breadth. In no case elementwidth shall be larger than stiffener spacing. In way of forcetransfer points and cutouts the mesh has to be refined whereapplicable. The ratio of element length to width shall not ex-ceed 4.

The element height of webs of primary support-ing member must not exceed one-third of the web height.Stiffeners, supporting plates against pressure loads, have to beincluded in the idealization. Buckling stiffeners may be disre-garded for the stress calculation.

7.10.3.6 Buckling strength of hatch cover structures

For hatch cover structures sufficient bucklingstrength is to be demonstrated.

The buckling strength assessment of coamingparts is to be done according to the Rules, Part 2 – Hull, 4.6.

Definitionsa = length of the longer side of a single plate field, in

[mm], (x-direction), see Fig. 7.10.3.6,b = breadth of the shorter side of a single plate field, in

[mm], (y-direction), see Fig. 7.10.3.6,α = aspect ratio of single plate field,

= a / bn = number of single plate field breadths within the partial

or total plate field,t = net plate thickness, in [mm],σx = membrane stress, in [N/mm²], in x-direction,σy = membrane stress, in [N/mm²],in y-direction,τ = shear stress, in [N/mm²], in the x-y plane,

E = modulus of elasticity, in [N/mm²], of the material= 2,06·105 N/mm2 for steel,

σF = minimum yield stress, in [N/mm²], of the material.Compressive and shear stresses are to be taken

positive, tension stresses are to be taken negative.

longitudinal: stiffener in the direction of the length atransverse: stiffener in the direction of the length b

Figure 7.10.3.6 General arrangement of panel

Note:If stresses in the x- and y-direction already con-

tain the Poisson-effect (calculated using FEM), the followingmodified stress values may be used. Both stresses σx* and σy

*are to be compressive stresses, in order to apply the stress re-duction according to the following formulae:

( ) 91,03,0 **yxx σσσ ⋅−=

( ) 91,03,0 **xyy σσσ ⋅−=

σx* , σy* = stresses containing the Poisson-effect

Where compressive stress fulfils the conditionσy

*< 0,3⋅σx*, then σy = 0 and σx = σx*.

Where compressive stress fulfils the conditionσx* < 0,3⋅σy

*, then σx = 0 and σy = σy*.

long. stiffener single field partial field

transverse stiffener

n⋅b

b

a

b mam


2013

F1 = correction factor for boundary condition atthe longitudinal stiffeners according to Table 7.10.3.6.

Table 7.10.3.6 Correction factor F1

Stiffeners sniped at bothends

1,00

Guidance values1 whereboth ends are effectivelyconnected to adjacentstructures

1,051,101,201,30

for flat barsfor bulb sectionsfor angle and tee-sectionsfor u-type sections2 andgirders of high rigidity

An average value of F1 is to be used for plate panels havingdifferent edge stiffeners.1 Exact values may be determined by direct calculations2 Higher value may be taken if it is verified by a buckling

strength check of the partial plate field using non-linearFEA and deemed appropriate by the Register but notgreater than 2,0.

σE = reference stress, in [N/mm²], taken equal to

=2

9,0

⋅

btE

Ψ = edge stress ratio taken equal to = σ2 / σ1 where

σ1 = maximum compressive stress,σ2 = minimum compressive stress or tension stress.S = safety factor (based on net scantling approach), taken

equal to:= 1.25 for hatch covers when subjected to the vertical

weather design load according to 7.10.2.1,= 1.10 for hatch covers when subjected to loads accord-

ing to 7.10.2.2 to 7.10.2.5.λ = reference degree of slenderness, taken equal to:

=e

F

K σσ⋅

K = buckling factor according to Table 7.10.3.6.1.-2.

7.10.3.6.1 Proof of top and lower hatch cover plating

Proof is to be provided that the following condition is com-plied with for the single plate field a ⋅ b:

3

2

221 3

e

FF

yx

e

Fy

y

e

Fx

x

K

SSB

K

S

KS

⋅

⋅⋅+

⋅⋅−

⋅

⋅+

⋅

⋅

σ

τ

σσσ

σ

σ

σ

σ

τ

≤1,0

The first two terms and the last term of theabove condition shall not exceed 1,0.

The reduction factors κx, κy and κτ are given inTable 7.10.3.6.1-2.Where σx ≤ 0 (tension stress), κx = 1,0.

Where σy ≤ 0 (tension stress), κy = 1,0.

The exponents e1, e2 and e3 as well as the factorB are to be taken as given by Table 7.10.3.6.1-1.

Table 7.10.3.6.1-1 Coefficients e1, e2, e3 and factor B

Exponents e1 - e3 andfactor B Plate panel

e141 xκ+

e241 yκ+

e321 τκκκ ⋅⋅+ yx

Bσx and σy positive(compression stress)

( )5yx κκ ⋅

Bσx or σy negative(tension stress)

1


2013

Table 7.10.3.6.1-2 Buckling and reduction factors for plane elementary plate panels

Buckling-Load Case

Edge stress ratioψ

Asp. ratio

ba=α Buckling factor K Reduction factor κ

01 ≥≥ψ1,1

4,8+

=ψ

K

10 −>>ψ ( )ψψ 1026,663,7 −−=K

1

1−≤ψ

1≥α

( ) 975,51 2 ⋅−= ψK

1=xκ for cλλ ≤

−= 2

22,01λλ

κ cx for cλλ >

( ) 25,112,025,1 ≤−= ψc

−+=

cc

c88,011

2λ

01 ≥≥ψ 1≥α( )1,1

1,2112

21 +⋅

+=

ψαFK

5,11 ≤≤ α

( )

+⋅

+=

1,111,211

2

21ψ

αFK

( )−− ψ

αψ 109,132

10 −>> ψ

5,1>α

( )1,1

11,2112

21ψ

α+

⋅

+= FK

22 87,187,5( α

αψ

+⋅−

−+ )106,8

2 ψα

( )4

131

ψα−

≤≤975,51 2

1 ⋅

−

=α

ψFK

2

1−≤ψ

( )4

13 ψα

−>

⋅

−

= 9675,31 2

1 αψFK

415375,0

−

+α

ψ

]87,1+

( )

−+−= 2

21λλ

κ RHFRcy

( ) 25,112,025,1 ≤−= ψc

−=

cR λλ 1 for cλλ <

22,0=R for cλλ ≥

−+=

cc

c88,011

2λ

01

91,01 12 ≥⋅

−−= c

K

Fpλ

5,022 −= λλ p for 31 2 ≤≤ pλ

01 11 ≥

−=αF

c

RTTc

H ≥

−+

−=4

22

λλ

31

1514

++=λ

λT

Explanations for boundary conditions - - - - - plate edge free──── plate edge simply supported


2013

01 ≥≥ψ13

1425,04 2

+

+

=ψ

αK

3

10 −≥>ψ

0>α( )ψ

α+

+= 11425,04 2K

( )ψψ 42,315 −−

4

11 −≥≥ψ 0>α2

31425,0 2ψ

α−

+=K

1=xκ for 7,0≤λ

51,01

2 +=

λκ x for 7,0>λ

3⋅= τKK

1≥α

+= 2

434,5α

τK

5

===

10 << α

+= 2

34,54α

τK

1=τκ for 84,0≤λ

λκτ

84,0= for 84,0>λ

Explanations for boundary conditions - - - - - plate edge free──── plate edge simply supported

7.10.3.6.2 Webs and flanges of primary supportingmembers

For non-stiffened webs and flanges of primarysupporting members sufficient buckling strength as for thehatch cover top and lower plating is to be demonstrated ac-cording to 7.10.3.6.1.

7.10.3.6.3 Proof of partial and total fields of hatch cov-ers

7.10.3.6.3.1 Longitudinal and transverse secondary stiff-eners

It is to be demonstrated that the continuous lon-gitudinal and transverse stiffeners of partial and total platefields comply with the conditions set out in 7.10.3.6.3.3through 7.10.3.6.3.4.

7.10.3.6.3.2 Effective width of top and lower hatch coverplating

For demonstration of buckling strength accord-ing to 7.10.3.6.3.3 through 7.10.3.6.3.4 the effective width ofplating may be determined by the following formulae:

bm = κx⋅b , for longitudinal stiffenersam = κy⋅a , for transverse stiffenerssee also Fig. 7.10.3.6.

The effective width of plating is not to be takengreater than the value obtained from 7.10.3.5.1.

The effective width e'm of stiffened flange platesof primary supporting members may be determined as fol-lows:

Figure 7.10.3.6.3.2-1 Stiffening parallel to web of primarysupporting member


2013

b < eme'm = n⋅ bm

n = integer number of stiffener spacings binside the effective breadth em accordingto 7.10.3.5.1

= int

meb

Figure 7.10.3.6.3.2-2 Stiffening perpendicular to web ofprimary supporting member

a ≥ eme'm = ⋅ <m mn a e

n = ⋅ ≤me2,7 1

ae = width of plating supported according to

7.10.3.5.1.For b ≥ em or a < em, respectively, b and a have

to be exchanged.am and bm for flange plates are in general to be

determined for ψ = 1.

Note:Scantlings of plates and stiffeners are in general

to be determined according to the maximum stresses σx(y) atwebs of primary supporting member and stiffeners, respec-tively. For stiffeners with spacing b under compression ar-ranged parallel to primary supporting members no value lessthan 0,25 ⋅ σF shall be inserted for σx(y=b).

The stress distribution between two primarysupporting members can be obtained by the following for-mula:

( ) ( )2 = ⋅ ⋅

x x1 1 1 2y yy 1 3 c 4 c 2 1 c 2ce e

σ σ − + − − + −

c1 = 2

1

x1

x0 c 1

σ≤ ≤

σ

c2 = ( )" "m1 m2

1,5 e e 0,5e

+⋅ −

e″m1 = proportionate effective breadth em1 or pro-portionate effective width e’m1 of primary sup-porting member 1 within the distance e, as ap-propriate,

e″m2 = proportionate effective breadth em2 or pro-portionate effective width e’m2 of primary sup-porting member 2 within the distance e, as ap-propriate,

σx1, σx2 = normal stresses in flange plates of adjacentprimary supporting member 1 and 2 withspacing e, based on cross-sectional propertiesconsidering the effective breadth or effectivewidth, as appropriate,

y = distance of considered location from primarysupporting member 1.

Shear stress distribution in the flange plates maybe assumed linearly.

7.10.3.6.3.3 Lateral buckling of secondary stiffeners

1≤+

SF

ba

σσσ

σa = uniformly distributed compressive stress,in [N/mm2], in the direction of the stiffeneraxis,

σa = σx , for longitudinal stiffeners,σa = σy , for transverse stiffeners,σb = bending stress, in [N/mm2], in the stiffener

=3

10

10⋅+

stZMM

M0 = bending moment, in [Nmm], due to the de-formation w of stiffener, taken equal to:

zf

zKi pc

wpFM−⋅

=0 , with ( )zf pc − > 0

M1 = bending moment, in [Nmm], due to thelateral load p equal to:

3

2

11024 ⋅

⋅⋅=

abpM , for longitudinal stiffeners,

( )3

2

1108 ⋅⋅

⋅⋅=

scbnbpM , for transverse stiffeners.

n is to be taken equal to 1 for ordinary transversestiffeners.

p = lateral load, in [kN/m²],FKi = ideal buckling force, in [N], of the stiffener

42

210⋅⋅⋅= xKix IE

aF π , for longitudinal stiffeners,

( )4

2

2

10⋅⋅⋅⋅

= yKiy IEbn

F π , for transv. stiffeners,

Ix, Iy = net moments of inertia, in [cm4], of thelongitudinal or transverse stiffener in-cluding effective width of attached platingaccording to 7.10.3.6.3.2. Ix and Iy are tocomply with the following criteria:


2013

4

3

1012 ⋅⋅

≥tbI x

4

3

1012 ⋅⋅

≥taI y

pz = nominal lateral load, in [N/mm2], of thestiffener due to σx ,σy and τ

+⋅⋅+

⋅

= 1

2

22 τσπσ yyxlzx ca

bbtp , for lon-

gitudinal stiffeners

+

⋅

+

⋅⋅

+⋅⋅= 1

2

212 τπσσta

Abnac

atp y

yxlxzy

, for transverse stiffeners

⋅+=

tbAx

xxl 1σσ

cx, cy = factor taking into account the stresses per-pendicular to the stiffener's axis and dis-tributed variable along the stiffener'slength

= ( )ψ+⋅ 15,0 , for 0 ≤ ψ ≤ 1

= ψ−15,0 , for ψ < 0

Ax, Ay= net sectional area, in [mm2], of the longi-tudinal or transverse stiffener, respec-tively, without attached plating

022

21

1 ≥

+⋅−=

bm

amEt Fσττ ,

for longitudinal stiffeners:

≥ba

2,0 : m1 = 1,47 m2 = 0,49

ba

< 2,0 : m1 = 1,96 m2 = 0,37

for transverse stiffeners:

≥⋅bna

0,5 : m1 = 0,37 2296,1

nm =

bna⋅

< 0,5 : m1 = 0,49 2247,1

nm =

w = w0 + w1

w0 = assumed imperfection, in [mm]

)10,250

,250

min(0baw x ≤ , for longitud. stiffeners,

)10,250

,250

min(0bnaw y

⋅≤ , for transverse stiffeners.

Note:For stiffeners sniped at both ends wo must not

be taken less than the distance from the midpoint of plating tothe neutral axis of the profile including effective width ofplating.

w1 = deformation of stiffener, in [mm], at mid-point of stiffener span due to lateral load p.

In case of uniformly distributed load the fol-lowing values for w1 may be used:

xIEabpw

⋅⋅⋅⋅⋅

= 7

4

1 10384 , for longitudinal stiffeners,

( )27

4

1 103845

sy cIEbnpaw

⋅⋅⋅⋅⋅⋅⋅⋅

= , for transverse stiffeners.

cf = elastic support provided by the stiffener, in[N/mm2]

i. For longitudinal stiffeners:

( )pxKixfx ca

Fc +⋅⋅= 12

2π

xa

xpx

cbt

Ic

−

⋅⋅⋅

⋅

+

=

1101291,01

1

3

4

222

+=

ab

bacxa , for a ≥ 2b

22

21

+=

bacxa , for a < 2b

ii. For transverse stiffeners:

( )( )pyKiysfy c

bnFcc +⋅

⋅⋅⋅= 12

2π

ya

ypy

cat

Ic

−

⋅

⋅⋅⋅

+

=

11012

91,01

1

3

4

222

⋅+

⋅=

bna

abncya , for abn 2≥⋅ ,

22

21

⋅

+=abncya , for bn ⋅ < 2a,

cs = factor accounting for the boundary con-ditions of the transverse stiffener

= 1,0 , for simply supported stiffeners,= 2,0 , for partially constraint stiffeners.

Wst= net section modulus of stiffener (long. ortransverse), in [cm³], including effectivewidth of plating according to7.10.3.6.3.2.

If no lateral load p is acting the bending stress σbis to be calculated at the midpoint of the stiffener span for thatfibre which results in the largest stress value. If a lateral load pis acting, the stress calculation is to be carried out for both fi-


2013

bres of the stiffener's cross sectional area (if necessary for thebiaxial stress field at the plating side).

7.10.3.6.3.4 Torsional buckling of secondary stiffeners

7.10.3.6.3.4.1 Longitudinal secondary stiffeners

The longitudinal ordinary stiffeners are to com-ply with the following criteria:

0,1≤⋅⋅

FT

x

KS

σσ

Tκ = coefficient taken equal to:

0,1=Tκ , for 2,0≤Tλ

22

1

TTK

λ−Φ+Φ= , for 2,0>Tλ

( )( )22,021,015,0 TT λλ +−+=Φ

=Tλ reference degree of slenderness takenequal to:

KiT

FT σ

σλ =

⋅+

⋅⋅= T

pKiT I

aI

IE 385,010

2

22επσ ω , in [N/mm2].

For IP, IT, Iω see Figure 7.10.3.6.3.4.1 and Table7.10.3.6.3.4.1.

ef

hw

tw tw tw

bf bf bf

t ft a

tw

ef = hw + tf / 2

C C C C

b1 b2b1

Figure 7.10.3.6.3.4.1 Dimensions of stiffener

IP = net polar moment of inertia of the stiff-ener, in [cm4], related to the point C,

IT = net St. Venant's moment of inertia of thestiffener, in [cm4],

Iω = net sectorial moment of inertia of the stiff-ener, in [cm6], related to the point C,

ε = degree of fixation taken equal to:

+⋅

+= −

334

43

34

43

101

w

w

th

tbI

a

ωπε

hW = web height, in [mm],tw = net web thickness, in [mm],bf = flange breadth, in [mm],tf = net flange thickness, in [mm],Aw = net web area equal to: www thA ⋅=

Af = net flange area equal to: fff tbA ⋅=

2f

wft

he += , in [mm].

Table 7.10.3.6.3.4.1 Moments of inertia

Section IP IT Iω

Flat bar4

3

103 ⋅

⋅ ww th

−

⋅⋅

w

www

htth 63,01

103 4

3

6

33

1036 ⋅

⋅ ww th

Sections withbulb or flange

422

103

−

⋅+

⋅ff

ww eAhA

−

⋅⋅

w

www

htth 63,01

103 4

3

+

−

⋅

⋅

f

fff

bttb

63,01103 4

3

for bulb and angle sections:

+

+

⋅

⋅⋅

Wf

Wffff

AAAAbeA 6.2

1012 6

22

for tee-sections:

6

23

1012 ⋅

⋅⋅ fff etb

7.10.3.6.3.4.2 Transverse secondary stiffeners

For transverse secondary stiffeners loaded bycompressive stresses and which are not supported by longitu-dinal stiffeners, sufficient torsional buckling strength is to bedemonstrated analogously in accordance with 7.10.3.6.3.4.1.


2013

7.10.4 Details of hatch covers

7.10.4.1 Container foundations on hatch covers

Container foundations are to be designed to thesatisfaction of the Register. The substructures of containerfoundations are to be designed for cargo and container loadsaccording to 7.10.2.6, applying the permissible stresses ac-cording to 7.10.3.1.1.

7.10.4.2 Weather tightness

Further to the following requirements IACS Rec.14 is applicable to hatch covers.

7.10.4.2.1 Packing material (General)

The packing material is to be suitable for all ex-pected service conditions of the ship and is to be compatiblewith the cargoes to be transported. The packing material is tobe selected with regard to dimensions and elasticity in such away that expected deformations can be carried. Forces are tobe carried by the steel structure only.

The packings are to be compressed so as to givethe necessary tightness effect for all expected operating con-ditions. Special consideration shall be given to the packing ar-rangement in ships with large relative movements betweenhatch covers and coamings or between hatch cover sections.

7.10.4.2.2 Dispensation of weather tight gaskets

For hatch covers of cargo holds solely for thetransport of containers, upon request by the owners and sub-ject to compliance with the following conditions the fitting ofweather tight gaskets according to 7.10.4.2.1 may be dis-pensed with:

• The hatchway coamings shall be not less than600 mm in height.

• The exposed deck on which the hatch covers arelocated is situated above a depth H(x). H(x) is tobe shown to comply with the following criteria:

hfdxH bfb ++≥)( , in [m],

dfb = draught, in [m], corresponding to the as-signed summer load line,

fb = minimum required freeboard, in [m], deter-mined in accordance with ICLL Reg. 28 asmodified by further regulations as applicable

h = 4,6 m for 750,Lx

LL

≤

= 6,9 m for 750,Lx

LL

>

• Labyrinths, gutter bars or equivalents are to befitted proximate to the edges of each panel inway of the coamings. The clear profile of theseopenings is to be kept as small as possible.

• Where a hatch is covered by several hatch coverpanels the clear opening of the gap in betweenthe panels shall be not wider than 50 mm.

• The labyrinths and gaps between hatch coverpanels shall be considered as unprotected open-

ings with respect to the requirements of intactand damage stability calculations.

• With regard to drainage of cargo holds and thenecessary fire-fighting system reference is madeto the sections of the Rules, Part 8 – Piping andPart 17.- Fire protection.

• Bilge alarms should be provided in each holdfitted with non-weathertight covers.

• Furthermore, Chapter 3 of IMO MSC/Circ. 1087is to be referred to concerning the stowage andsegregation of containers containing dangerousgoods.

7.10.4.2.3 Drainage arrangements

Cross-joints of multi-panel covers are to be pro-vided with efficient drainage arrangements.

7.10.5 Hatch coaming strength criteria

7.10.5.1 Local net plate thickness of coamings

The net thickness of weather deck hatch coam-ings shall not be less than the larger of the following values:

F

Apstσ⋅

⋅=95,0

2,14 , in [mm],

1006 1

minLt += , in [mm],

s = stiffener spacing , in [m],L1 = L, need not be taken greater than 300 m.Longitudinal strength aspects are to be observed.

7.10.5.2 Net scantling of secondary stiffeners ofcoamings

The stiffeners must be continuous at the coam-ing stays. For stiffeners with both ends constraint the elasticnet section modulus W, in [cm3], and net shear area AS, in[cm2], calculated on the basis of net thickness, must not be lessthan:

AF

plsW ⋅⋅⋅= 283σ

F

As

plsAσ

⋅⋅⋅= 10

l = secondary stiffener span, in [m], to betaken as the spacing of coaming stays,

s = stiffener spacing, in [m].For sniped stiffeners at coaming corners section

modulus and shear area at the fixed support have to be in-creased by 35 %. The gross thickness of the coaming plate atthe sniped stiffener end shall not be less than

( )F

A slsptσ

5,06,19 −⋅⋅⋅= , in [mm]

Horizontal stiffeners on hatch coamings, whichare part of the longitudinal hull structure, are to be designedaccording to the Rules, Part 2 - Hull.


2013

7.10.5.3 Coaming stays

Coaming stays are to be designed for the loadstransmitted through them and permissible stresses according to7.10.3.1.1.

7.10.5.3.1 Coaming stay section modulus

The net section modulus W of coaming stayswith a height of hs < 1,6 m and which are to be designed forthe load pA, shall not be less than:

AsF

pheW ⋅⋅⋅= 2526σ

, in [cm3]

e = spacing of coaming stays, in [m]Coaming stays of coamings having a height of

1,6 m or more are to be designed using direct calculations un-der consideration of the permissible stresses according to7.10.3.1.1. The effective breadth of the coaming plate shall notbe larger than the effective plate breadth according to7.10.3.5.1.

Coaming stays are to be supported by appropri-ate substructures. Face plates may only be included in the cal-culation if an appropriate substructure is provided and weldingprovides an adequate joint.

7.10.5.3.2 Web thickness of coaming stays

Web gross thickness at the root point shall notbe less than:

SW

AS

Fw t

hphe

t +⋅⋅

⋅=σ2

hw = web height of coaming stay at its lowerend, in [m]

ts = corrosion addition, in [mm], according to7.10.7

Webs are to be connected to the deck by filletwelds on both sides with a throat thickness of a=0,44⋅tw. Thesize of welding for toes of webs at the lower end of coamingstays should be according to the Rules, Part 2 – Hull, Section15.

7.10.5.3.3 Coaming stays under friction load

For coaming stays, which transfer friction forcesat hatch cover supports, sufficient fatigue strength is to beverified according to Rules, Part 2 - Hull, refer to 7.10.6.2.2.

7.10.5.4 Further requirements for hatch coamings

7.10.5.4.1 Longitudinal strength

Hatch coamings which are part of the longitudi-nal hull structure are to be designed according to the require-ments for longitudinal strength of the Rules, Part 2 – Hull,Section 4.

For structural members welded to coamings andfor cutouts in the top of coamings sufficient fatigue strength isto be verified according to Section 16.

Longitudinal hatch coamings with a length ex-ceeding 0,1·L m are to be provided with tapered brackets orequivalent transitions and a corresponding substructure at bothends. At the end of the brackets they are to be connected to thedeck by full penetration welds of minimum 300 mm in length.

7.10.5.4.2 Local details

If the design of local details is not regulated in7.10.5, local details are to comply with the Rules, Part 2 –Hull for the purpose of transferring the loads on the hatch cov-ers to the hatch coamings and, through them, to the deckstructures below. Hatch coamings and supporting structuresare to be adequately stiffened to accommodate the loadingfrom hatch covers, in longitudinal, transverse and vertical di-rections.

Structures under deck are to be checked againstthe load transmitted by the stays.

Unless otherwise stated, weld connections andmaterials are to be dimensioned and selected in accordancewith the Rules, Part 2 – Hull.

7.10.5.4.3 Stays

On ships carrying cargo on deck, such as timber,coal or coke, the stays are to be spaced not more than 1,5 mapart.

7.10.5.4.4 Extend of coaming plates

Coaming plates are to extend to the lower edgeof the deck beams; they are to be flanged or fitted with facebars or half-round bars. Fig. 7.10.5.4.4 gives an example.

Fig. 7.10.5.4.4 Example for the extend of coaming plates

7.10.5.4.5 Drainage arrangement at the coaming

If drain channels are provided inside the line ofgasket by means of a gutter bar or vertical extension of thehatch side and end coaming, drain openings are to be providedat appropriate positions of the drain channels.

Drain openings in hatch coamings are to be ar-ranged with sufficient distance to areas of stress concentration(e.g. hatch corners, transitions to crane posts).

Drain openings are to be arranged at the ends ofdrain channels and are to be provided with non-return valvesto prevent ingress of water from outside. It is unacceptable toconnect fire hoses to the drain openings for this purpose.

If a continuous outer steel contact between coverand ship structure is arranged, drainage from the space be-tween the steel contact and the gasket is also to be providedfor.


2013

7.10.6 Closing arrangements

7.10.6.1 Securing devices

7.10.6.1.1 General

Securing devices between cover and coamingand at cross-joints are to be installed to provide weathertight-ness. Sufficient packing line pressure is to be maintained.

Securing devices must be appropriate to bridgedisplacements between cover and coaming due to hull defor-mations.

Securing devices are to be of reliable construc-tion and effectively attached to the hatchway coamings, decksor covers. Individual securing devices on each cover are tohave approximately the same stiffness characteristics.

Sufficient number of securing devices is to beprovided at each side of the hatch cover considering the re-quirements of 7.10.3.4.2. This applies also to hatch coversconsisting of several parts.

The materials of stoppers, securing devices andtheir weldings are to be to the Register satisfaction. Specifica-tions of the materials are to be shown in the drawings of thehatch covers.

7.10.6.1.2 Rod cleats

Where rod cleats are fitted, resilient washers orcushions are to be incorporated.

7.10.6.1.3 Hydraulic cleats

Where hydraulic cleating is adopted, a positivemeans is to be provided so that it remains mechanically lockedin the closed position in the event of failure of the hydraulicsystem.

7.10.6.1.4 Cross-sectional area of the securing devices

The gross cross-sectional area, in [cm2], of thesecuring devices is not to be less than:

lSD ksqA ⋅⋅⋅= 28,0

q = packing line pressure, in [N/mm], mini-mum 5 N/mm,

sSD = spacing between securing devices in [m],not to be taken less than 2 m,

e

Flk

=

σ235 , σF is the minimum yield strength

of the material, in [N/mm2], but is not tobe taken greater than 0,7 · σm, where σm isthe tensile strength of the material, in[N/mm2].

e = 0,75 for 235>Fσ N/mm²

= 1,00 for 235≤Fσ N/mm².

Rods or bolts are to have a gross diameter notless than 19 mm for hatchways exceeding 5 m² in area.

Securing devices of special design in which sig-nificant bending or shear stresses occur may be designed asanti-lifting devices according to 7.10.6.1.5. As load the pack-

ing line pressure q multiplied by the spacing between securingdevices sSD is to be applied.

7.10.6.1.5 Anti lifting devices

The securing devices of hatch covers, on whichcargo is to be lashed, are to be designed for the lifting forcesresulting from loads according to 7.10.2.6.4, refer Figure7.10.6.1.5. Unsymmetrical loadings, which may occur inpractice, are to be considered. Under these loadings theequivalent stress in the securing devices is not to exceed:

lV k

150=σ , in [N/mm2].

Chapter 5.6 of IACS Rec. 14 should be referredto for the omission of anti lifting devices.

Figure 7.10.6.1.5 Lifting forces at a hatch cover

7.10.6.2 Hatch cover supports, stoppers andsupporting structures

7.10.6.2.1 Horizontal mass forces

For the design of the securing devices againstshifting the horizontal mass forces Fh = m⋅a are to be calcu-lated with the following accelerations:

ax = 0,2⋅g in longitudinal direction,ay = 0,5⋅g in transverse direction,m = sum of mass of cargo lashed on the hatch

cover and mass of hatch cover.

7.10.6.2.2 Hatch cover supports

For the transmission of the support forces re-sulting from the load cases specified in 7.10.2.6 and of thehorizontal mass forces specified in 7.10.6.2.1, supports are tobe provided which are to be designed such that the nominalsurface pressures in general do not exceed the following val-ues:

nn pdp ⋅=max, in [N/mm2]

d = 3,75 – 0,015⋅Ldmax = 3,0dmin = 1,0 in general

= 2,0 for partial loading conditions, see7.10.2.6.4.1

pn = see Table 7.10.7.2For metallic supporting surfaces not subjected to

relative displacements the nominal surface pressure applies:


2013

pn max = 3⋅ pn , in [N/mm²]

Drawings of the supports must be submitted. Inthe drawings of supports the permitted maximum pressuregiven by the material manufacturer related to long time stressmust be specified.

Tab. 7.10.6.2.2 Permissible nominal surface pressure pn

pn , in [N/mm²], when loaded bySupport material

Vertical force Horizontal force(on stoppers)

Hull structuralsteel 25 40

Hardened steel 35 50Plastic materials

on steel 50 -

Where large relative displacements of the sup-porting surfaces are to be expected, the use of material havinglow wear and frictional properties is recommended.

If necessary, sufficient abrasive strength may beshown by tests demonstrating an abrasion of support surfacesof not more than 0,3 mm per year in service at a total distanceof shifting of 15 000 m/year.

The substructures of the supports must be ofsuch a design, that a uniform pressure distribution is achieved.

Irrespective of the arrangement of stoppers, thesupports must be able to transmit the following force Ph in thelongitudinal and transverse direction:

dPP V

h ⋅= µ

Pv = vertical supporting forceµ = frictional coefficient

= 0,5 in general.For non-metallic, low-friction support materials

on steel, the friction coefficient may be reduced but not to beless than 0,35 and to the satisfaction of the Rules, Part 24 –Non-Metalic Materials.

Supports as well as the adjacent structures andsubstructures are to be designed such that the permissiblestresses according to 7.10.3.1.1 are not exceeded.

For substructures and adjacent structures of sup-ports subjected to horizontal forces Ph, a fatigue strengthanalysis is to be carried out according to the Rules, Part 2 –Hull, Section 16.

7.10.6.2.3 Hatch cover stoppers

Hatch covers shall be sufficiently securedagainst horizontal shifting. Stoppers are to be provided forhatch covers on which cargo is carried.

The greater of the loads resulting from7.10.2.6.2 and 7.10.6.2.1 is to be applied for the dimensioningof the stoppers and their substructures.

The permissible stress in stoppers and their sub-structures, in the cover, and of the coamings is to be deter-mined according to 7.10.3.1.1. In addition, the provisions in7.10.6.2.2 are to be observed.

7.10.7 Corrosion addition and steel renewal

7.10.7.1 Corrosion addition for hatch covers andhatch coamings

The scantling requirements of the above sectionsimply the following general corrosion additions tS:

Table 7.10.7.1 Corrosion additions tS for hatch covers andhatch coamings

Application Structure ts [mm]

Hatch covers 1,0Weather deckhatches of con-tainer ships, carcarriers, papercarriers, passengervessels

Hatch coamings according to theRules, Part 2 - Hul

Hatch covers in gen-eral 2,0

Weather exposedplating and bottomplating of doubleskin hatch covers

1,5

Internal structure ofdouble skin hatchcovers and closedbox girders

1,0

Hatch coamings notpart of the longitu-dinal hull structure

1,5

Hatch coamings partof the longitudinalhull structure

according to theRules, Part 2 - Hul

Weather deckhatches of allother ship typescovered by theserequirements

Coaming stays andstiffeners 1,5

7.10.7.2 Steel renewal

For single skin hatch covers and for the platingof double skin hatch covers, steel renewal is required wherethe gauged thickness is less than tnet + 0,5 mm. Where thegauged thickness is within the range tnet + 0,5 mm and tnet +1,0 mm, coating (applied in accordance with the coatingmanufacturer’s requirements) or annual gauging may beadopted as an alternative to steel renewal. Coating is to bemaintained in GOOD condition, as defined in the Rules, Part1 – General Requirements, Ch.5.

For the internal structure of double skin hatchcovers, thickness gauging is required when hatch cover top orbottom plating renewal is to be carried out or when this isdeemed necessary, at the discretion of the Register’s surveyor,on the basis of the plating corrosion or deformation condition.In these cases, steel renewal for the internal structures is re-quired where the gauged thickness is less than tnet.

For corrosion addition tS = 1,0 mm the thicknessfor steel renewal is tnet and the thickness for coating or annualgauging is when gauged thickness is between tnet and tnet + 0,5mm.


2013

7.10.8 Hatch covers and hatch coamings of cargoholds of bulk carriers, ore carriers andcombination carriers

7.10.8.1 Application and definitions

These requirements apply to all bulk carriers, orecarriers and combination carriers, as defined in the Rules, Part1 – General requirements, Chapter 1 – General information,4.2 and are for all cargo hatch covers and hatch forward andside coamings on exposed decks in position 1 (see Section7.1.4). Other loadings are also to be considered, if necessary,according to the requirements of the Rules.

The strength requirements are applicable tohatch covers and hatch coamings of stiffened plate construc-tion. The secondary stiffeners and primary supporting mem-bers of the hatch covers are to be continuous over the breadthand length of the hatch covers, as far as practical. When this isimpractical, sniped end connections are not to be used and ap-propriate arrangements are to be adopted to ensure sufficientload carrying capacity.

The spacing of primary supporting membersparallel to the direction of secondary stiffeners is not to exceed1/3 of the span of primary supporting members.

The secondary stiffeners of the hatch coamingsare to be continuous over the breadth and length of the hatchcoamings.

These requirements are in addition to the re-quirements of the ICLL, 1966.

The net minimum scantlings of hatch covers areto fulfil the strength criteria given in:

- Section 7.10.8.3.3, for plating,- Section 7.10.8.3.4, for secondary stiffeners,- Section 7.10.8.3.5, for primary supporting mem-

bers,the critical buckling stress check in Section

7.10.8.3.6 and the rigidity criteria given in Section 7.10.8.3.7,adopting the load model given in Section 7.10.8.2.

The net minimum scantlings of hatch coamingsare to fulfil the strength criteria given in:

- Section 7.10.8.4.2, for plating,- Section 7.10.8.4.3, for secondary stiffeners,- Section 7.10.8.4.4, for coaming stays,

adopting the load model given in Section7.10.8.4.1.

The net thicknesses, tnet, are the member thick-nesses necessary to obtain the minimum net scantlings re-quired by Section 7.10.8.3 and Section 7.10.8.4.

The required gross thicknesses are obtained byadding the corrosion additions, tk, given in Section 7.10.8.6, totnet.

Material for the hatch covers and coamings is tobe steel according to the requirements for ship’s hull.

These requirements do not apply to CSR BulkCarriers.

7.10.8.2 Hatch cover load model

The pressure p, in [kN/m2], on the hatch coverspanels is given by:

For ships of 100 m in length and above:

3.3425.025.0

3.343.34 ≥

−⋅

−+=

Lxpp FP , for

hatch ways located at the freeboard deckpFP = pressure at the forward perpendicular

= 49.1 + (L-100)aa = 0.0726, for type B freeboard ships

0.356, for ships with reduced free-board

L = freeboard length, in [m], as defined inthe ICLL, 1966, to be taken not greaterthan 340 m

x = distance, in [m], of the mid length ofthe hatch cover under examinationfrom the forward end of L.

Where a position 1 hatchway is located at leastone superstructure standard height higher than the freeboarddeck, the pressure p may be 34,3 kN/m2.

For ships less than 100 m in length:

Lx

LxLp ⋅−⋅−⋅+= 6.3)

351(

38.15 ≥ 0.195L+14.9,

for hatch ways located at the freeboard deck.Where two or more panels are connected by

hinges, each individual panel is to be considered separately.

7.10.8.3 Hatch cover strength criteria

7.10.8.3.1 Allowable stress checks

The normal and shear stresses σ and τ in thehatch cover structures are not to exceed the allowable values,σa and τa, in [N/mm2], given by:

σa = 0.8 σFτa = 0.46 σF

σF = being the minimum upper yield stress,in [N/mm2], of the material.

The normal stress in compression of the attachedflange of primary supporting members is not to exceed 0,8times the critical buckling stress of the structure according tothe buckling check as given in Section 7.10.8.3.6.

The stresses in hatch covers that are designed asa grillage of longitudinal and transverse primary supportingmembers are to be determined by a grillage or a FEM analysis.

When a beam or a grillage analysis is used, thesecondary stiffeners are not to be included in the attachedflange area of the primary members.

When calculating the stresses σ and τ, the netscantlings are to be used.

7.10.8.3.2 Effective cross-sectional area of panel flangesfor primary supporting members

The effective flange area Af, in [cm2], of the at-tached plating, to be considered for the yielding and bucklingchecks of primary supporting members, when calculated by


2013

means of a beam or grillage model, is obtained as the sum ofthe effective flange areas of each side of the girder web as ap-propriate:

( )∑=nf

eff tbA 10

where:nf = 2 if attached plate flange extends on

both sides of girder web= 1 if attached plate flange extends on

one side of girder web onlyt = net thickness of considered attached

plate, in [mm]bef = effective breadth, in [m], of attached

plate flange on each side of girder web= bp, but not to be taken greater than

0.165 lbp = half distance, in [m], between the con-

sidered primary supporting memberand the adjacent one

l = span, in [m], of primary supportingmembers

7.10.8.3.3 Local net plate thickness

The local net plate thickness t, in [mm], of thehatch cover top plating is not to be less than:

Fp

psFtσ95.0

8.15=

but to be not less than 1% of the spacing of thestiffener or 6 mm if that is greater.where:

Fp = factor for combined membrane and bendingresponse

= 1.50 in general= 1.90σ / σa, for σ / σa ≥ 0.8, for the attached

plate flange of primary supporting memberss = stiffener spacing, in [m]p = pressure, in [kN/m2], as defined in Section

7.10.8.2σ = as defined in Section 7.10.8.3.5σa = as defined in Section 7.10.8.3.1.

7.10.8.3.4 Net scantlings of secondary stiffeners

The required minimum section modulus, Z, in[cm3], of secondary stiffeners of the hatch cover top plate,based on stiffener net member thickness, are given by:

a

psZσ12

1000 2l=

where:l = secondary stiffener span, in [m], to be

taken as the spacing, in [m], of primarysupporting members or the distance be-tween a primary supporting member andthe edge support, as applicable. Whenbrackets are fitted at both ends of all sec-ondary stiffener spans, the secondary stiff-ener span may be reduced by an amountequal to 2/3 of the minimum brackets armlength, but not greater than 10% of thegross span, for each bracket.

s = secondary stiffener spacing, in [m]p = pressure, in [kN/m2], as defined in Section

7.10.8.2σa = as defined in Section 7.10.8.3.1.

The net section modulus of the secondary stiff-eners is to be determined based on an attached plate width as-sumed equal to the stiffener spacing.

7.10.8.3.5 Net scantlings of primary supportingmembers

The section modulus and web thickness of pri-mary supporting members, based on member net thickness,are to be such that the normal stress σ in both flanges and theshear stress τ, in the web, do not exceed the allowable valuesσa and τa, respectively, defined in Section 7.10.8.3.1.

The breadth of the primary supporting memberflange is to be not less than 40% of their depth for laterally un-supported spans greater than 3.0 m. Tripping brackets attachedto the flange may be considered as a lateral support for pri-mary supporting members.

The flange outstand is not to exceed 15 times theflange thickness.

7.10.8.3.6 Critical buckling stress check

7.10.8.3.6.1 Hatch cover plating

The compressive stress σ in the hatch coverplate panels, induced by the bending of primary supportingmembers parallel to the direction of secondary stiffeners, isnot to exceed 0,8 times the critical buckling stress σC1, to beevaluated as defined below:

σC1 = σE1 when σE1 ≤ σF/2= σF [1 - σF / (4 σE1)] when σE1 > σF/2

where:σF = minimum upper yield stress, in [N/mm2], of

the material

σE1 =2

10006.3

stE

E = modulus of elasticity, in [N/mm2]= 2,06⋅ 105 for steel

t = net thickness, in [mm], of plate panels = spacing, in [m], of secondary stiffeners

The mean compressive stress σ in each of thehatch cover plate panels, induced by the bending of primarysupporting members perpendicular to the direction of secon-dary stiffeners, is not to exceed 0.8 times the critical bucklingstress σC2, to be evaluated as defined below:

σC2 = σE2 when σE2 ≤ σF/2= σF [1 - σF / (4 σE2)] when σE2 > σF/2where:

σF = minimum upper yield stress, in [N/mm2], ofthe material

σE2 =2

10009.0

sstEm


2013

m =1.1

1.21

22

+Ψ

+

s

ssc

l

E = modulus of elasticity, in [N/mm2]= 2.06⋅105 for steel

t = net thickness, in [mm], of plate panelss = length, in [m], of the shorter side of the plate

panells = length, in [m], of the longer side of the plate

panelΨ = ratio between smallest and largest compres-

sive stressc = 1.3 when plating is stiffened by primary

supporting membersc = 1.21 when plating is stiffened by secondary

stiffeners of angle or T typec = 1.1 when plating is stiffened by secondary

stiffeners of bulb typec = 1.05 when plating is stiffened by flat bar

The biaxial compressive stress in the hatch coverpanels, when calculated by means of FEM shell elementmodel, is to be in accordance with the Rules as deemedequivalent to the above criteria.

7.10.8.3.6.2 Hatch cover secondary stiffeners

The compressive stress σ in the top flange ofsecondary stiffeners, induced by the bending of primary sup-porting members parallel to the direction of secondary stiffen-ers, is not to exceed 0.8 times the critical buckling stress σCS,to be evaluated as defined below:

σCS = σES when σES ≤ σF/2= σES [1 - σF / (4 σES)] when σES > σF/2

where:

σF = minimum upper yield stress, in [N/mm2],of the material

σES = ideal elastic buckling stress, in [N/mm2],of the secondary stiffener,

= minimum between σE3 and σE4

σE3 = 0.001 E Ia / (A l2)E = modulus of elasticity, in [N/mm2]

= 2,06⋅105 for steelIa = moment of inertia, in [cm4], of the sec-

ondary stiffener, including a top flangeequal to the spacing of secondary stiff-eners

A = cross-sectional area, in [cm2], of the sec-ondary stiffener, including a top flangeequal to the spacing of secondary stiff-eners

l = span, in [m], of the secondary stiffener

σE4 =p

t

p

wII

EmKm

IIE

385.010 2

224

2+

+

l

π

K = 64

410

wIEC

π

l

m = number of half waves, given by the fol-lowing table:

0 < K < 4 4 < K < 36 36 < K < 144 (m-1)2 m2 < K ≤ m2(m+1)2

m 1 2 3 m

Iw = sectorial moment of inertia, in [cm6], ofthe secondary stiffener about its connec-tion with the plating

= 633

1036

−ww th, for flat bar secondary stiff-

eners

= 623

1012

−wff hbt, for "Tee" secondary

stiffeners

= ( ) ( )[ ] 6222

2310342

12−+++

+wfwwwfff

wf

wf hbthhbbthb

hb

for angles and bulb secondary stiffenersIp = polar moment of inertia, in [cm4], of the

secondary stiffener about its connectionwith the plating

= 43

103

−ww th, for flat bar secondary stiffeners

= 423

103

−

+ ffw

ww tbhth , for flanged secon-

dary stiffeners

It = St Venant's moment of inertia, in [cm4], ofthe secondary stiffener without top flange

= 43

103

−ww th, for flat bar secondary stiffeners

= 433 1063,0131 −

−+

f

fffww b

ttbth , for

flanged secondary stiffenershw, tw = height and net thickness, in [mm], of the

secondary stiffener, respectivelybf, tf = width and net thickness, in [mm], of the

secondary stiffener bottom flange, respec-tively

s = spacing, in [m], of secondary stiffenersC = spring stiffness exerted by the hatch cover

top plating = 3

3

3

310

1000

33,113

−

+

w

pwp

pp

ts

thks

tEk

kp = 1 - ηp to be taken not less than zero; forflanged secondary stiffeners, kp need notbe taken less than 0,1

ηp =1Eσ

σ


2013

σ = as defined in Section 7.10.8.3.5σE1 = as defined in Section 7.10.8.3.6.1tp = net thickness, in [mm], of the hatch cover

plate panel.For flat bar secondary stiffeners and buckling

stiffeners, the ratio h/tW is to be not greater than 15·k0,5, where:h, tW = height and net thickness of the stiffener,

respectivelyk = 235/σF

σF = minimum upper yield stress, in [N/mm2],of the material.

7.10.8.3.6.3 Web panels of hatch cover primary support-ing members

This check is to be carried out for the web panelsof primary supporting members, formed by web stiffeners orby the crossing with other primary supporting members, theface plate (or the bottom cover plate) or the attached top coverplate.

The shear stress τ in the hatch cover primarysupporting members web panels is not to exceed 0,8 times thecritical buckling stress τC, to be evaluated as defined below:

τC = τE when τE ≤ τF/2= τF [1 - τF / (4 τE)] when τE > τF/2

where:σF = minimum upper yield stress, in

[N/mm2], of the material

τF = σF / 3

τE = 0.9 kt E [tpr,n / (1000 d)]2

E = modulus of elasticity, in [N/mm2]= 2,06⋅105 for steel

tpr,n = net thickness, in [mm], of primarysupporting member

kt = 5,35 + 4,0 / (a / d)2

a = greater dimension, in [m], of webpanel of primary supporting member

d = smaller dimension, in [m], of webpanel of primary supporting member.

For primary supporting members parallel to thedirection of secondary stiffeners, the actual dimensions of thepanels are to be considered.

For primary supporting members perpendicularto the direction of secondary stiffeners or for hatch coversbuilt without secondary stiffeners, a presumed square panel ofdimension d is to be taken for the determination of the stressτC. In such a case, the average shear stress τ between the val-ues calculated at the ends of this panel is to be considered.

7.10.8.3.7 Deflection limit and connections betweenhatch cover panelsLoad bearing connections between the hatch

cover panels are to be fitted with the purpose of restricting therelative vertical displacements.

The vertical deflection of primary supportingmembers is to be not more than 0.0056⋅l, where l is the great-est span of primary supporting members.

7.10.8.4 Hatch coamings and local details

7.10.8.4.1 Load model

The pressure pcoam, in [kN/m2], on the No. 1forward transverse hatch coaming is given by:

pcoam = 220, when a forecastle is fitted in ac-cordance with the Rules, Part 2 - Hull,17.2.

= 290 in the other casesThe pressure pcoam, in [kN/m2], on the other

coamings is given by:pcoam = 220.

7.10.8.4.2 Local net plate thickness

The local net plate thickness t, in [mm], of thehatch coaming plating is given by:

coamcoama

coam Sp

st,

9,14σ

=

where:s = secondary stiffener spacing, in [m]pcoam = pressure, in [kN/m2], as defined in

Section 7.10.8.4.1Scoam = safety factor to be taken equal to

1.15σa,coam = 0.95 σF.The local net plate thickness is to be not less

than 9.5 mm.

7.10.8.4.3 Net scantlings of longitudinal and transversesecondary stiffeners

The required section modulus Z, in [cm3], of thelongitudinal or transverse secondary stiffeners of the hatchcoamings, based on net member thickness, is given by:

coamaP

coamcoam

cmpsS

Z,

21000σl

=

where:m = 16 in general

= 12 for the end spans of stiffenerssniped at the coaming corners

Scoam = safety factor to be taken equal to 1.15l = span, in [m], of secondary stiffenerss = spacing, in [m], of secondary stiffenerspcoam = pressure, in [kN/m2], as defined in

7.10.8.4.1cp = ratio of the plastic section modulus to

the elastic section modulus of the sec-ondary stiffeners with an attached platebreadth, in [mm], equal to 40 t, where tis the plate net thickness

= 1.16 in the absence of more preciseevaluation

σa,coam = 0.95 σF


2013

7.10.8.4.4 Net scantlings of coaming stays

The required minimum section modulus, Z, in[cm3], and web thickness, tw, in [mm], of coaming stays de-signed as beams with flange connected to the deck or snipedand fitted with a bracket (see Fig. 7.10.8.4.4-1 and 7.10.8.4.4-2) at their connection with the deck, based on member netthickness, are given by:

coama

coamC psHZ

,

2

21000

σ=

coama

coamCw h

psHt

,

1000τ

=

HC = stay height, in [m]s = stay spacing, in [m]h = stay depth, in [mm], at the connec-

tion with the deckpcoam = pressure, in [kN/m2], as defined in

7.10.8.4.1σa,coam = 0.95σF

τa,coam = 0.5 σF

For calculating the section modulus of coamingstays, their face plate area is to be taken into account onlywhen it is welded with full penetration welds to the deck plat-ing and adequate underdeck structure is fitted to support thestresses transmitted by it.

For other designs of coaming stays, such as, forexamples, those shown in Fig. 7.10.8.4.4-3 and 7.10.8.4.4-4,the stress levels in 7.10.8.3.1 apply and are to be checked atthe highest stressed locations.

7.10.8.4.5 Local details

The design of local details is to comply with therequirement of the Rules, Part 2 - Hull, 9.5 for the purpose oftransferring the pressures on the hatch covers to the hatchcoamings and, through them, to the deck structures below.Hatch coamings and supporting structures are to be adequatelystiffened to accommodate the loading from hatch covers, inlongitudinal, transverse and vertical directions.

Underdeck structures are to be checked againstthe load transmitted by the stays, adopting the same allowablestresses specified in Section 7.10.8.4.4.

Unless otherwise stated, weld connections andmaterials are to be dimensioned and selected in accordancewith the Rules, Part 2 - Hull, Part 25 - Metallic materials andPart 26 - Welding.

Double continuous welding is to be adopted forthe connections of stay webs with deck plating and the weldthroat is to be not less than 0.44 tW, where tW is the grossthickness of the stay web.

Toes of stay webs are to be connected to thedeck plating with deep penetration double bevel welds ex-tending over a distance not less than 15% of the stay width.

7.10.8.5 Closing arrangements

7.10.8.5.1 Securing devices

The strength of securing devices is to complywith the following requirements:

Panel hatch covers are to be secured by appro-priate devices (bolts, wedges or similar) suitably spacedalongside the coamings and between cover elements.

Arrangement and spacing are to be determinedwith due attention to the effectiveness for weather-tightness,depending upon the type and the size of the hatch cover, aswell as on the stiffness of the cover edges between the secur-ing devices.

The net sectional area of each securing device isnot to be less than:

A = 1.4 a / f , [cm2]where:

a = spacing, in [m], of securing devices,not being taken less than 2 m

f = (σY / 235)e

σY = specified minimum upper yield stress,in [N/mm2], of the steel used for fabri-cation, not to be taken greater than70% of the ultimate tensile strength.

e = 0.75 for σY > 235= 1.0 for σY < 235

Rods or bolts are to have a net diameter not lessthan 19 mm for hatchways exceeding 5 m2 in area.

Between cover and coaming and at cross-joints,a packing line pressure sufficient to obtain weathertightness isto be maintained by the securing devices.

For packing line pressures exceeding 5 N/mm,the cross section area is to be increased in direct proportion.The packing line pressure is to be specified.

The cover edge stiffness is to be sufficient tomaintain adequate sealing pressure between securing devices.The moment of inertia, I, of edge elements is not to be lessthan:

I = 6 p a4 [cm4]p = packing line pressure in [N/mm],

minimum 5 N/mm.a = spacing, in [m], of securing devices.Securing devices are to be of reliable construc-

tion and securely attached to the hatchway coamings, decks orcovers. Individual securing devices on each cover are to haveapproximately the same stiffness characteristics.

Where rod cleats are fitted, resilient washers orcushions are to be incorporated.

Where hydraulic cleating is adopted, a positivemeans is to be provided to ensure that it remains mechanicallylocked in the closed position in the event of failure of the hy-draulic system.

7.10.8.5.2 Stoppers

Hatch covers are to be effectively secured, bymeans of stoppers, against the transverse forces arising from apressure of 175 kN/m2.


2013

With the exclusion of No.1 hatch cover, hatchcovers are to be effectively secured, by means of stoppers,against the longitudinal forces acting on the forward end aris-ing from a pressure of 175 kN/m2.

No. 1 hatch cover is to be effectively secured, bymeans of stoppers, against the longitudinal forces acting onthe forward end arising from a pressure of 230 kN/m2. Thispressure may be reduced to 175 kN/m2 when a forecastle isfitted in accordance with the Rules, Part 2 - Hull, 17.2.

The equivalent stress:i. in stoppers and their supporting structures,

andii. calculated in the throat of the stopper

weldsis not to exceed the allowable value of 0.8 σY.

7.10.8.5.3 Materials and welding

Stoppers or securing devices are to be manufac-tured of materials, including welding electrodes, meeting rele-vant requirements of the Rules, Part 25 - Metallic materialsand Part 26 - Welding.

7.10.8.6 Corrosion addition and steel renewal

7.10.8.6.1 Hatch covers

For all the structure (plating and secondary stiff-eners) of single skin hatch covers, the corrosion addition tk isto be 2.0 mm.

For pontoon hatch covers, the corrosion additionis to be:

- 2.0 mm, for the top and bottom plating- 1.5 mm, for the internal structures.For single skin hatch covers and for the plating

of pontoon hatch covers, steel renewal is required where thegauged thickness is less than tnet + 0,5 mm. Where the gaugedthickness is within the range tnet + 0,5 mm and tnet + 1,0 mm,coating (applied in accordance with the coating manufac-turer’s requirements) or annual gauging may be adopted as analternative to steel renewal. Coating is to be maintained inGOOD condition, as defined in Rules, Part 1 – General re-quirements, Chapter 5 – Surveys of ships in service.

For the internal structure of pontoon hatch cov-ers, thickness gauging is required when plating renewal is tobe carried out or when this is deemed necessary, at the discre-tion of the Register's Surveyor, on the basis of the plating cor-rosion or deformation condition. In these cases, steel renewalfor the internal structures is required where the gauged thick-ness is less than tnet.

7.10.8.6.2 Hatch coamings

For the structure of hatch coamings and coamingstays, the corrosion addition tk is to be 1.5 mm.

Steel renewal is required where the gaugedthickness is less than tnet + 0,5 mm. Where the gauged thick-ness is within the range tnet + 0,5 mm and tnet + 1,0 mm, coat-ing (applied in accordance with the coating manufacturer’s re-quirements) or annual gauging may be adopted as an alterna-tive to steel renewal. Coating is to be maintained in GOODcondition, as defined in Rules, Part 1 – General requirements,Chapter 5 – Surveys of ships in service, Section 1.2.

Fig. 7.10.8.4.4-1

Fig. 7.10.8.4.4-2

Fig. 7.10.8.4.4- 3


2013

Fig. 7.10.8.4.4-4

7.10.9 Construction of portable hatchway coversspecified in 7.10.1.1

7.10.9.1 These covers are to be so constructed as to pre-vent their accidental opening under the effect of sea andweather.

7.10.9.2 Portable beams are to be placed in sockets of thecoamings and locked therein. Where portable beams are ofsliding type, efficient devices are to be provided for lockingthem when the hatchway is either closed or open.

7.10.9.3 If the hatchway covers are jointed on the port-able beam, a vertical flat bar of at least 60 mm in height is tobe attached by welding to the upper flange of the beam.

7.10.9.4 The width of each bearing surface for hatchwaycovers is to be at least 65 mm.

7.10.9.5 Where the covers are made of wood, their fin-ished thickness is to be at least 60 mm for a load intensitysustained by the cover equal to 17,16 kPa and less. If the loadintensity exceeds this value, the above thickness is to be in-creased by 1,5 mm per 0,981 kPa of overload. In all cases, theportable beams of the hatchway provided with wooden coversare to be spaced not more than 1,5 m apart.

Independently of the provisions of 7.10.1 to7.10.8, all covers made of steel are to have the thickness oftheir plating at least 0,01 times the spacing of stiffeners or 6mm, whichever is the greater.

If the covers are made of light alloy, the mini-mum thickness of their top plating is to be specially consid-ered by the Register in each case.

7.10.9.6 The hatchways in positions 1 and 2 are to beprotected by at least two layers of tarpaulins.

Tarpaulins are to be tightly pressed against thehatchway coamings with the aid of battens and wedges, forwhich purpose the coamings, as well as horizontal stiffeners, iffitted, are to be provided with cleats of at least 65 mm wideand 10 mm thick; edges of the cleats are to be rounded so thatthe possibility of cutting the wedges is brought to the mini-mum. Cleats are to be spaced not more than 600 mm centre tocentre; the cleats along each side or end are to not be morethan 150 mm form hatch corners. The cleats are to be somounted as to provide setting of wedges in them in the fore to

aft direction on the side coamings, and from the sides to centreline direction on the end coamings.

Wedges are to be not less than 200 mm in lengthand 50 mm in width with a taper of not more than 1:6, and athickness not less than 13 mm at the thinnest point.

7.10.9.7 Steel bars or other equivalent means are to beprovided in order to efficiently and independently secure eachsection of hatchway covers after the tarpaulins are batteneddown. Sections of hatchway covers of more than 1,5 m inlength are to be secured by at least two such securing appli-ances.

7.10.10 Hatch beams and cover stiffeners of variablecross section (ICLL Regulation 15 and 16)

7.10.10.1 To avoid stresses and deflections exceedingthose given in the above Regulations along construction ele-ments of variable cross section, the required section moduluscalculated as for constriction elements of constant cross sec-tion is to be increased by a factor C1 expressed by:

IW I1W1

l1

l

Figure 7.10.9.1

C1 =407

80231.

..+

−−+

γγα ;

where:

α =ll1 ;

WW1=γ ;

The value of factor C1 obtained by the formula isnot to be less than unity.

l1, l, W1 and W are indicated on the Figure7.10.9.1.

7.10.10.2 The moment of inertia is likewise to be in-creased by the factor C2 expressed by:

ββα⋅+

−+=

320181 3

2 .C ;

The value factor of C obtained by the formula isnot to be less than unity.

I1 and I are indicated on the Figure 7.10.9.1..The use of the above formulae is limited to the

determination of the strength of hatch beams and covers inwhich abrupt changes in the section of the face material do nooccur along the length of the beam or cover.


2013

7.11 HATCHWAYS OF CARGOTANKS IN TYPE "A" SHIPS

7.11.1 Openings for hatchways of the cargo tanks ontankers are to be of round or oval form. Height of the coam-ings of cargo tank hatchways is not to be regulated by theRegister. Construction of the coamings of cargo tank hatch-ways shall comply with the requirements of the Rules, Part 2 -Hull, 17.2.8.

7.11.2 Covers of hatches and tank cleaning openingsare to be made of steel, bronze or brass. Use of other materialsis subject to special consideration by the Register in each case.

In ships carrying flammable liquids in bulk useof light alloys for covers of hatches and tank cleaning open-ings is not permitted.

7.11.3 Covers of the cargo tank hatchways are to bepermanently attached and tight, when secured, under the innerpressure of liquid carried in tanks to a head of at least 2.5 m.Tightness is to be provided by a rubber or other suitable gasketbeing resistant to the liquids which are carried in the cargotanks.

7.11.4 The plate of the cargo tank hatchway covers is tobe at least 12 mm in thickness if it is of steel. The cover plateis to be reinforced by stiffeners made of flat bars not less than80 x 12 mm in size, and spaced at every 600 mm of the coverlength, or the cover is to be of spherical shape.

7.11.5 The hatchway cover is to be provided with asighting port having an inner diameter of 150 mm and closedby a cover of similar construction.

7.11.6 Materials and designs of cargo tank hatchwaycovers in ships intended to carry flammable liquids are to beso selected as to preclude spark formation during opening andclosing the covers.

7.12 OPENINGS IN WATERTIGHTSUBDIVISION BULKHEADS ANDTHEIR CLOSING APPLIANCES

7.12.1 General

7.12.1.1 Unless expressly provided otherwise, the presentchapter covers the ships to which the requirements of theRules, Part 5 - Subdivision apply. For other ships the require-ments of this chapter apply only to bulkheads provided in ac-cordance with the Rules, Part 2 – Hull, 10, for these ships therequirements may be relaxed, and the degree of relaxation is tobe specially considered by the Register in each case.

7.12.2 Openings in watertight bulkheads below thebulkhead deck in passenger ships

7.12.2.1 The number of openings in watertight subdivi-sion bulkheads is to be reduced to the minimum compatiblewith the design and proper working of the ship, satisfactorymeans are to be provided for closing these openings.

7.12.2.2 Where pipes, scuppers, electric cables, etc., arecarried through watertight bulkheads, arrangements are to be

made to ensure the watertight integrity of the bulkheads andthe requirements of the Rules, Part 8 - Piping, 1.6 and Part12-Electrical equipment, 16.8 also is to be taken into consid-eration.

Valves not forming part of a piping system areto not be permitted in watertight bulkheads.

Lead or other heat sensitive materials are to notbe used in systems which penetrate watertight bulkheads,where deterioration of such systems in the event of fire wouldimpair the watertight integrity of the bulkheads.

7.12.2.3 No doors, manholes, or access openings arepermitted in watertight transverse bulkheads dividing a cargospace from an adjoining cargo space, except as provided in7.12.2.20 and in the Rules, Part 5 – Subdivision, 2.12.

7.12.2.4 Subject to requirement 7.12.2.22, not more thanone door, apart from the doors to shaft tunnels, may be fittedin each watertight bulkhead within spaces containing the mainand auxiliary propulsion machinery including boilers servingthe needs of propulsion. Where two or more shafts are fitted,the tunnels are to be connected by an intercommunicating pas-sage. There shall be only one door between the machineryspace and the tunnel spaces where two shafts are fitted andonly two doors where there are more than two shafts. All thesedoors are to be of the sliding type and are to be so located as tohave their sills as high as practicable. The hand gear for oper-ating these doors from above the bulkhead deck is to be situ-ated outside the spaces containing the machinery.

7.12.2.5 Watertight doors, except as provided in7.12.2.20 or in the Rules, Part 5 – Subdivision, 2.12, are to bepower-operated sliding doors complying with the require-ments of 7.12.2.9 to 7.12.2.16 capable of being closed simul-taneously from the central operating console at the navigationbridge in not more than 60 s with the ship in the upright posi-tion.

7.12.2.6 The means of operation whether by power or byhand of any power-operated sliding watertight door are to becapable of closing the door with the ship listed to 15o eitherway. Consideration is to also be given to the forces which mayact on either side of the door as may be experienced whenwater is flowing through the opening applying a static headequivalent to a water height of at least 1 m above the sill onthe centreline of the door.

7.12.2.7 Watertight door controls, including hydraulicpiping and electric cables, are to be kept as close as practica-ble to the bulkhead in which the doors are fitted, in order tominimise the likelihood of them being involved in any damagewhich the ship may sustain. The positioning of watertightdoors and their controls is to be such that if the ship sustainsdamage within one fifth of the breadth of the ship, such dis-tance being measured at right angles to the centreline at thelevel of the deepest subdivision draught, the operation of thewatertight doors clear of the damaged portion of the ship is notimpaired.

7.12.2.8 All power-operated sliding watertight doors areto be provided with means of indication which will show at allremote operating positions whether the doors are open orclosed. Remote operating positions are only to be at the navi-gation bridge as required by paragraph 7.12.2.9.5 and at thelocation where hand operation above the bulkhead deck is re-quired by paragraph 7.12.2.9.4.


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7.12.2.9 Each power-operated sliding watertight door:.1 is to have a vertical or horizontal motion;.2 is to, subject to requirement 7.12.2.22, be

normally limited to a maximum clearopening width of 1.2 m. The Register maypermit larger doors only to the extent con-sidered necessary for the effective opera-tion of the ship provided that other safetymeasures, including the following, aretaken into consideration:.1 special consideration is to be given to

the strength of the door and its closingappliances in order to prevent leak-ages; and

.2 the door is to be located inboard thedamage zone B/5;

.3 is to be fitted with the necessary equip-ment to open and close the door usingelectric power, hydraulic power, or anyother form of power that is acceptable tothe Register;

.4 is to be provided with an individual hand-operated mechanism. It is to be possible toopen and close the door by hand at thedoor itself from either side, and in addi-tion, close the door from an accessible po-sition above the bulkhead deck with an allround crank motion or some other move-ment providing the same degree of safetyacceptable to the Register. Direction ofrotation or other movement is to be clearlyindicated at all operating positions. Thetime necessary for the complete closure ofthe door, when operating by hand gear, isnot to exceed 90 s with the ship in the up-right

.5 is to be provided with controls for openingand closing the door by power from bothsides of the door and also for closing thedoor by power from the central operatingconsole at the navigation bridge;

.6 is to be provided with an audible alarm,distinct from any other alarm in the area,which will sound whenever the door isclosed remotely by power and which shallsound for at least 5 s but no more than 10 sbefore the door begins to move and shallcontinue sounding until the door is com-pletely closed. In the case of remote handoperation it is sufficient for the audiblealarm to sound only when the door ismoving. Additionally, in passenger areasand areas of high ambient noise the Reg-ister may require the audible alarm to besupplemented by an intermittent visualsignal at the door; and

.7 is to have an approximately uniform rateof closure under power. The closure time,from the time the door begins to move tothe time it reaches the completely closedposition shall in no case be less than 20 sor more than 40 s with the ship in the up-right position.

7.12.2.10 The electrical power required for power-operated sliding watertight doors is to be supplied from theemergency switchboard either directly or by a dedicated dis-tribution board situated above the bulkhead deck. The associ-ated control, indication and alarm circuits are to be suppliedfrom the emergency switchboard either directly or by a dedi-cated distribution board situated above the bulkhead deck andbe capable of being automatically supplied by the transitionalsource of emergency electrical power in the event of failure ofeither the main or emergency source of electrical power.

7.12.2.11 Power-operated sliding watertight doors are tohave either:

.1 a centralised hydraulic system with twoindependent power sources each consistingof a motor and pump capable of simulta-neously closing all doors. In addition,there shall be for the whole installationhydraulic accumulators of sufficient ca-pacity to operate all the doors at least threetimes, i.e. closed-open-closed, against anadverse list of 15º. This operating cycle isto be capable of being carried out when theaccumulator is at the pump cut-in pressure.The fluid used is to be chosen consideringthe temperatures liable to be encounteredby the installation during its service. Thepower operating system is to be designedto minimise the possibility of having a sin-gle failure in the hydraulic piping ad-versely affect the operation of more thanone door. The hydraulic system is to beprovided with a low-level alarm for hy-draulic fluid reservoirs serving the power-operated system and a low gas pressurealarm or other effective means of moni-toring loss of stored energy in hydraulicaccumulators. These alarms are to be audi-ble and visual and are to be situated on thecentral operating console at the navigationbridge; or

.2 an independent hydraulic system for eachdoor with each power source consisting ofa motor and pump capable of opening andclosing the door. In addition, there shall bea hydraulic accumulator of sufficient ca-pacity to operate the door at least threetimes, i.e. closed-open-closed, against anadverse list of 15º. This operating cycle isto be capable of being carried out when theaccumulator is at the pump cut-in pressure.The fluid used is to be chosen consideringthe temperatures liable to be encounteredby the installation during its service. A lowgas pressure group alarm or other effectivemeans of monitoring loss of stored energyin hydraulic accumulators are to be pro-vided at the central operating console onthe navigation bridge. Loss of stored en-ergy indication at each local operating po-sition is also to be provided; or

.3 an independent electrical system and mo-tor for each door with each power sourceconsisting of a motor capable of openingand closing the door. The power source is


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to be capable of being automatically sup-plied by the transitional source of emer-gency electrical power in the event of fail-ure of either the main or emergency sourceof electrical power and with sufficient ca-pacity to operate the door at least threetimes, i.e. closed-open-closed, against anadverse list of 15º, see also the Rules, Part12-Electrical equipment, 5.10.

For the systems specified in 7.12.2.11.1,7.12.2.11.2 and 7.12.2.11.3, provision is to be made as fol-lows: Power systems for power-operated watertight slidingdoors are to be separate from any other power system. A sin-gle failure in the electric or hydraulic power-operated systemsexcluding the hydraulic actuator is not to prevent the hand op-eration of any door.

7.12.2.12 Control handles are to be provided at each sideof the bulkhead at a minimum height of 1.6 m above the floorand are to be so arranged as to enable persons passing throughthe doorway to hold both handles in the open position withoutbeing able to set the power closing mechanism in operationaccidentally. The direction of movement of the handles inopening and closing the door is to be in the direction of doormovement and is to be clearly indicated.

7.12.2.13 As far as practicable, electrical equipment andcomponents for watertight doors are to be situated above thebulkhead deck and outside hazardous areas and spaces.

7.12.2.14 The enclosures of electrical components neces-sarily situated below the bulkhead deck shall provide suitableprotection against the ingress of water.*

* Refer to the following IEC publication529(1976):

.1 electrical motors, associated circuits andcontrol components; protected to IPX 7 stan-dard;

.2 door position indicators and associated cir-cuit components; protected to IPX 8 standard;and

.3 door movement warning signals; protectedto IPX 6 standard.Other arrangements for the enclosures of electri-

cal components may be fitted provided the Administration issatisfied that an equivalent protection is achieved. The waterpressure IPX 8 shall be based on the pressure that may occurat the location of the component during flooding for a periodof 36 h.

7.12.2.15 Electric power, control, indication and alarm cir-cuits are to be protected against fault in such a way that a fail-ure in one door circuit will not cause a failure in any otherdoor circuit. Short circuits or other faults in the alarm or indi-cator circuits of a door are not to result in a loss of power op-eration of that door. Arrangements are to be such that leakageof water into the electrical equipment located below the bulk-head deck will not cause the door to open.

7.12.2.16 A single electrical failure in the power operatingor control system of a power-operated sliding watertight dooris not to result in a closed door opening. Availability of thepower supply is to be continuously monitored at a point in theelectrical circuit as near as practicable to each of the motors

required by 7.12.2.11. Loss of any such power supply shouldactivate an audible and visual alarm at the central operatingconsole at the navigation bridge.

7.12.2.17 The central operating console at the navigationbridge is to have a “master mode” switch with two modes ofcontrol: a “local control” mode which shall allow any door tobe locally opened and locally closed after use without auto-matic closure, and a “doors closed” mode which shall auto-matically close any door that is open. The “doors closed”mode shall automatically close any door that is open. The“doors closed” mode shall permit doors to be opened locallyand shall automatically re-close the doors upon release of thelocal control mechanism. The “master mode” switch is nor-mally to be in the “local control” mode. The “doors closed”mode is only to be used in an emergency or for testing pur-poses. Special consideration is to be given to the reliability ofthe “master mode” switch.

7.12.2.18 The central operating console at the navigationbridge is to be provided with a diagram showing the locationof each door, with visual indicators to show whether each dooris open or closed. A red light shall indicate a door is fully openand a green light shall indicate a door is fully closed. Whenthe door is closed remotely the red light shall indicate the in-termediate position by flashing. The indicating circuit is to beindependent of the control circuit for each door.

7.12.2.19 It is not to be possible to remotely open any doorfrom the central operating console.

7.12.2.20 If the Register is satisfied that such doors are es-sential, watertight doors of satisfactory construction may befitted in watertight bulkheads dividing cargo between deckspaces. Such doors may be hinged, rolling or sliding doors butare not to be remotely controlled. They are to be fitted at thehighest level and as far from the shell plating as practicable,but in no case are to the outboard vertical edges be situated ata distance from the shell plating which is less than one fifth ofthe breadth of the ship, as defined in regulation 2, such dis-tance being measured at right angles to the centreline at thelevel of the deepest subdivision draught.

7.12.2.21 Should any such doors be accessible during thevoyage, they are to be fitted with a device which prevents un-authorised opening. When it is proposed to fit such doors, thenumber and arrangements shall receive the special considera-tion of the Register.

7.12.2.22 Portable plates on bulkheads are not to be per-mitted except in machinery spaces.

The Register may permit not more than onepower-operated sliding watertight door in each watertightbulkhead larger than those specified in paragraph 7.12.2.9.2 tobe substituted for these portable plates, provided these doorsare intended to remain closed during navigation except in caseof urgent necessity at the discretion of the master. These doorsneed not meet the requirements of paragraph 7.12.2.9.4 re-garding complete closure by hand-operated gear in 90 s.

7.12.2.23 Where trunkways or tunnels for access fromcrew accommodation to the stokehold, for piping, or for anyother purpose are carried through watertight bulkheads, theyare to be watertight and in accordance with the requirementsof the Rules, Part 2-Hull, 11.7. The access to at least one endof each such tunnel or trunkway, if used as a passage at sea, isto be through a trunk extending watertight to a height suffi-


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cient to permit access above the bulkhead deck. The access tothe other end of the trunkway or tunnel may be through a wa-tertight door of the type required by its location in the ship.Such trunkways or tunnels are not to extend through the firstsubdivision bulkhead abaft the collision bulkhead.

7.12.2.24 Where it is proposed to fit tunnels piercing wa-tertight bulkheads, these shall receive the special considerationof the Register.

7.12.2.25 Where trunkways in connection with refriger-ated cargo and ventilation or forced draught trunks are carriedthrough more than one watertight bulkhead, the means of clo-sure at such openings are to be operated by power and be ca-pable of being closed from a central position situated abovethe bulkhead deck.

7.12.2.26 Doors are to be made of steel. Use of other ma-terials for doors is to be specially considered by the Register ineach case.

7.12.2.27 Doors shall withstand the pressure of water headof a height measured from the lower edge of the doorway tothe underside of the bulkhead deck plating at the centre line,but not less than 5 m of water column.

7.12.2.28 Stresses in the door frame and door plate underthe pressure head specified in 7.12.2.27 are not to exceed 0,6times the upper yield stress of their material.

7.12.2.29 When closed, doors are to be tight under thepressure of water head of the height specified in 7.12.2.27.

7.12.2.30 For doors in watertight bulkheads located in wayof the internal watertight subdivision boundaries and the ex-ternal watertight boundaries necessary to ensure compliancewith the relevant subdivision and damage stability regulationsIACS unified interpretation SC 156 is to be applied.

This unified interpretation does not apply todoors located in external boundaries above equilibrium or in-termediate waterplanes.

7.12.2.31 For the requirements relating to the accesses thatlead to spaces below the bulkhead deck specified in SOLASRegulation II-1/17-1, Integrity of the hull and superstructure,damage prevention and control on ro-ro passenger ships, seealso IACS unified interpretation SC 220.

7.12.3 Openings in watertight bulkheads andinternal decks in cargo ships

7.12.3.1 The number of openings in watertight subdivi-sions is to be kept to a minimum compatible with the designand proper working of the ship. Where penetrations of water-tight bulkheads and internal decks are necessary for access,piping, ventilation, electrical cables, etc., arrangements are tobe made to maintain the watertight integrity. The Register maypermit relaxation in the watertightness of openings above thefreeboard deck, provided that it is demonstrated that any pro-gressive flooding can be easily controlled and that the safetyof the ship is not impaired.

7.12.3.2 Doors provided to ensure the watertight integrityof internal openings which are used while at sea are to besliding watertight doors capable of being remotely closed fromthe bridge and are also to be operable locally from each side ofthe bulkhead. Indicators are to be provided at the control posi-tion showing whether the doors are open or closed, and an

audible alarm is to be provided at the door closure. The power,control and indicators are to be operable in the event of mainpower failure. Particular attention is to be paid to minimisingthe effect of control system failure. Each power-operatedsliding watertight door is to be provided with an individualhand-operated mechanism. It is to be possible to open andclose the door by hand at the door itself from both sides.

7.12.3.3 Access doors and access hatch covers normallyclosed at sea, intended to ensure the watertight integrity of in-ternal openings, are to be provided with means of indicationlocally and on the bridge showing whether these doors orhatch covers are open or closed. A notice is to be affixed toeach such door or hatch cover to the effect that it is not to beleft open.

7.12.3.4 Watertight doors or ramps of satisfactory con-struction may be fitted to internally subdivide large cargospaces, provided that the Register is satisfied that such doorsor ramps are essential. These doors or ramps may be hinged,rolling or sliding doors or ramps, but are not to be remotelycontrolled. Should any of the doors or ramps be accessibleduring the voyage, they are to be fitted with a device whichprevents unauthorised opening.

7.12.3.5 Other closing appliances which are kept perma-nently closed at sea to ensure the watertight integrity of inter-nal openings are to be provided with a notice which is to be af-fixed to each such closing appliance to the effect that it is to bekept closed. Manholes fitted with closely bolted covers neednot be so marked.

7.12.3.6 In all tankers, where there is permanent accessfrom a pipe tunnel to the cargo pump room, a watertight dooris to be fitted. A watertight door, in addition to bridge opera-tion, is to be capable of being manually closed from outsidethe cargo pump-room entrance.

7.12.3.7 For doors in watertight bulkheads located in wayof the internal watertight subdivision boundaries and the ex-ternal watertight boundaries necessary to ensure compliancewith the relevant subdivision and damage stability regulations,see IACS unified interpretation SC 156.

7.12.4 Manholes in watertight subdivision bulkheads

7.12.4.1 The requirements of 7.9 relating to the manholeslocated on the freeboard deck, raised quarter deck or the firsttier of superstructures are generally applicable to the manholesfitted in the watertight subdivision bulkheads.

No manholes are permitted:.1 in the collision bulkhead below the bulkhead

deck for ships having subdivision distinguishingmark in the class notation, and below the free-board deck for other ships;

.2 in watertight subdivision bulkheads separating acargo space from an adjacent cargo space or afuel oil tank.

7.12.5 Construction and initial tests of watertightdoors, sidescuttles, etc.

7.12.5.1 In all ships:.1 the design, materials and construction of

all watertight doors, sidescuttles, gangwayand cargo ports, valves, pipes, ash-chutes


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and rubbish-chutes referred to in theseregulations are to be to the satisfaction ofthe Register;

.2 such valves, doors and mechanisms are tobe suitably marked to ensure that they maybe properly used to provide maximumsafety; and

.3 the frames of vertical watertight doors areto have no groove at the bottom in whichdirt might lodge and prevent the doorclosing properly.

7.12.5.2 In passenger ships and cargo ships watertightdoors are to be tested by water pressure to a head up to thebulkhead deck or freeboard deck respectively. Where testingof individual doors is not carried out because of possible dam-age to insulation or outfitting items, testing of individual doorsmay be replaced by a prototype pressure test of each type andsize of door with a test pressure corresponding at least to thehead required for the intended location. The prototype test isto be carried out before the door is fitted. The installationmethod and procedure for fitting the door on board shall cor-respond to that of the prototype test. When fitted on board,each door is to be checked for proper seating between thebulkhead, the frame and the door.

7.13 STRENGTH AND SECURINGOF SMALL HATCHES ON THE

EXPOSED FORE DECK

7.13.1 General

7.13.1.1 The strength of, and securing devices for, smallhatches fitted on the exposed fore deck are to comply with therequirements of this Section.

7.13.1.2 Small hatches in the context of this Section arehatches designed for access to spaces below the deck and arecapable to be closed weather-tight or watertight, as applicable.Their opening is normally 2.5 square meters or less.

7.13.1.3 Hatches designed for use of emergency escapeare to comply with the requirements of this Section, excepting7.13.4.1 (i) and (ii), 7.13.5.3 and 7.13.6.

7.13.1.4 Securing devices of hatches designed for emer-gency escape are to be of a quick-acting type (e.g., one actionwheel handles are provided as central locking devices forlatching/unlatching of hatch cover) operable from both sidesof the hatch cover.

7.13.2 Application

7.13.2.1 These requirements are applicable to smallhatches on the exposed deck over the forward 0.25L for:

All ship types of sea going service of length 80m or more, where the height of the exposed deck in way of thehatch is less than 0.1L or 22 m above the summer load water-line, whichever is the lesser.

7.13.2.2 The ship length L is as defined in 1.2.2.1.

7.13.2.3 These requirements do not apply to CSR BulkCarriers and Oil Tankers.

7.13.3 Strength

7.13.3.1 For small rectangular steel hatch covers, theplate thickness, stiffener arrangement and scantlings are to bein accordance with Table 7.13.3.1, and Figure 7.13.3.1-1.Stiffeners, where fitted, are to be aligned with the metal-to-metal contact points, required in 7.13.5.1, see Figure 7.13.3.1-1. Primary stiffeners are to be continuous. All stiffeners are tobe welded to the inner edge stiffener, see Figure 7.13.3.1-2.

7.13.3.2 The upper edge of the hatchway coamings is tobe suitably reinforced by a horizontal section, normally notmore than 170 to 190 mm from the upper edge of the coam-ings.

7.13.3.3 For small hatch covers of circular or similarshape, the cover plate thickness and reinforcement is to be ac-cording to the requirements of the Rules.

7.13.3.4 For small hatch covers constructed of materialsother than steel, the required scantlings are to provide equiva-lent strength.

7.13.4 Primary Securing Devices

7.13.4.1 Small hatches located on exposed fore decksubject to the application of this Section are to be fitted withprimary securing devices such that their hatch covers can besecured in place and weather-tight by means of a mechanismemploying any one of the following methods:

i) Butterfly nuts tightening onto forks(clamps),

ii) Quick acting cleats, oriii) Central locking device.

7.13.4.2 Dogs (twist tightening handles) with wedges arenot acceptable.

7.13.5 Requirements for Primary Securing

7.13.5.1 The hatch cover is to be fitted with a gasket ofelastic material. This is to be designed to allow a metal tometal contact at a designed compression and to prevent overcompression of the gasket by green sea forces that may causethe securing devices to be loosened or dislodged. The metal-to-metal contacts are to be arranged close to each securing de-vice in accordance with Figure 7.13.3.1-1, and of sufficientcapacity to withstand the bearing force.

7.13.5.2 The primary securing method is to be designedand manufactured such that the designed compression pressureis achieved by one person without the need of any tools.

7.13.5.3 For a primary securing method using butterflynuts, the forks (clamps) are to be of robust design. They are tobe designed to minimise the risk of butterfly nuts being dis-lodged while in use; by means of curving the forks upward, araised surface on the free end, or a similar method. The platethickness of unstiffened steel forks is not to be less than 16mm. An example arrangement is shown in Figure 7.13.3.1-2

7.13.5.4 For small hatch covers located on the exposeddeck forward of the fore-most cargo hatch, the hinges are to befitted such that the predominant direction of green sea willcause the cover to close, which means that the hinges are nor-mally to be located on the fore edge.

7.13.5.5 On small hatches located between the mainhatches, for example between Nos. 1 and 2, the hinges are to


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be placed on the fore edge or outboard edge, whichever ispracticable for protection from green water in beam sea andbow quartering conditions.

7.13.6 Secondary Securing Device

Small hatches on the fore deck are to be fittedwith an independent secondary securing device e.g. by meansof a sliding bolt, a hasp or a backing bar of slack fit, which iscapable of keeping the hatch cover in place, even in the eventthat the primary securing device became loosened or dis-lodged. It is to be fitted on the side opposite to the hatch coverhinges.

Table 7.13.3.1Scantlings for Small Steel Hatch Covers on the Fore Deck

Primary stiffeners Secondary stiffenersNominal size[mm x mm]

Cover plate thickness[mm] Flat Bar [mm x mm]; number

630 x 630 8 - -630 x 830 8 100 x 8 ; 1 -830 x 630 8 100 x 8 ; 1 -830 x 830 8 100 x 10 ; 1 -

1030 x 1030 8 120 x 12 ; 1 80 x 8 ; 21330 x 1330 8 150 x 12 ; 1 100 x 10 ; 2


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Nominal size 630 x 630 Nominal size 630 x 830



Hinge Primary stiffener

• Securing device / metal to metal contact Secondary stiffener

Figure 7.13.3.1-1Arrangement of stiffeners


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(Note: Dimensions in millimetres)

1. butterfly nut2. bolt3. pin4. centre of pin5. fork (clamp) plate6. hatch cover7. gasket8. hatch coaming9. bearing pad welded on the bracket of a toggle bolt for metal to metal contact10. stiffener11. inner edge stiffener

Figure 7.13.3.1-2Example of a primary securing method

7.14 STRENGTH REQUIREMENTSFOR FORE DECK FITTINGS AND

EQUIPMENT

7.14.1 General

7.14.1.1 This Section provides strength requirements toresist green sea forces for the following items located withinthe forward quarter length:

air pipes, ventilator pipes and their closing de-vices, the securing of windlasses.

7.14.1.2 For windlasses, these requirements are addi-tional to those appertaining to the anchor and chain perform-ance criteria in Section 3.

7.14.1.3 Where mooring winches are integral with theanchor windlass, they are to be considered as part of thewindlass.

7.14.2 Application

7.14.2.1 These requirements are applicable to the deckfittings and equipment on the exposed deck over the forward0.25L for:

All ship types of sea going service of length 80m or more, where the height of the exposed deck in way of theitem is less than 0.1L or 22 m above the summer load water-line, whichever is the lesser.

7.14.2.2 The ship length L is as defined in 1.2.2.1.


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7.14.2.3 These requirements do not apply to CSR OilTankers. The requirements of this Section concerning wind-lasses do not apply to CSR Bulk Carriers.

7.14.3 Applied Loading

7.14.3.1 Air pipes, ventilator pipes and their closingdevices

7.14.3.1.1 The pressures p, in [kN/m2], acting on air pipes,ventilator pipes and their closing devices may be calculatedfrom:

psd CCCVp 25.0 ⋅= ρwhere:

ρ = density of sea water (1.025 t/m3)V = velocity of water over the fore deck

(13.5 m/sec)Cd = shape coefficient

= 0.5 for pipes, 1.3 for air pipe or venti-lator heads in general, 0.8 for an airpipe or ventilator head of cylindricalform with its axis in the vertical direc-tion.

Cs = slamming coefficient (3.2)Cp = protection coefficient:

= 0.7, for pipes and ventilator heads lo-cated immediately behind a breakwateror forecastle,

= 1.0, elsewhere and immediately behinda bulwark.

7.14.3.1.2 Forces acting in the horizontal direction on thepipe and its closing device may be calculated from 7.14.3.1.1using the largest projected area of each component.

7.14.3.2 Windlasses

7.14.3.2.1 The following pressures and associated areas areto be applied (see Figure 7.14.3.2.1):

- 200 kN/m2 normal to the shaft axis and awayfrom the forward perpendicular, over the pro-jected area in this direction,

- 150 kN/m2 parallel to the shaft axis and actingboth inboard and outboard separately, over themultiple of f times the projected area in this di-rection, where f is defined as:f = 1+ B/H, but not greater than 2.5

where:B = width of windlass measured parallel to

the shaft axis,H = overall height of windlass.

7.14.3.2.2 Forces in the bolts, chocks and stoppers securingthe windlass to the deck are to be calculated. The windlass issupported by N bolt groups, each containing one or morebolts, see Figure 7.14.3.2.2.

7.14.3.2.3 The axial force Ri in bolt group (or bolt) i, posi-tive in tension, may be calculated from:

xiixxi IAxhPR /⋅=

yiiyyi IAyhPR /⋅=

and Ri = Rxi + Ryi - Rsi

where:Px = force, in [kN], acting normal to the

shaft axisPy = force, in [kN], acting parallel to the

shaft axis, either inboard or outboardwhichever gives the greater force inbolt group i

h = shaft height above the windlassmounting, in [cm]

xi , yi = x and y coordinates of bolt group ifrom the centroid of all N bolt groups,positive in the direction opposite tothat of the applied force, in [cm]

Ai = cross sectional area of all bolts ingroup i, in [cm2]

Ix = ΣAi xi2 for N bolt groups

Iy = ΣAi yi2 for N bolt groups

Rs = static reaction at bolt group i, due toweight of windlass.

7.14.3.2.4 Shear forces Fxi , Fyi applied to the bolt group i,and the resultant combined force Fi may be calculated from:

NgMPF xxi /)( α−=

NgMPF yyi /)( α−=

and5.022 )( yixii FFF +=

where:α = coefficient of friction (0.5)M = mass of windlass, in [tonnes]g = gravity acceleration (9.81 m/sec2)N = number of bolt groups.

7.14.3.2.5 Axial tensile and compressive forces in7.14.3.2.3 and lateral forces in 7.14.3.2.4 are also to be con-sidered in the design of the supporting structure.

7.14.4 Strength Requirements

7.14.4.1 Air pipes, ventilator pipes and their closingdevices

7.14.4.1.1 These requirements are additional to the Rules,Part 8 – Pipes, 5.1 and 1.3.

7.14.4.1.2 Bending moments and stresses in air and venti-lator pipes are to be calculated at critical positions: at penetra-tion pieces, at weld or flange connections, at toes of support-ing brackets. Bending stresses in the net section are not to ex-ceed 0.8 σy , where σy is the specified minimum yield stress or0.2% proof stress of the steel at room temperature, see theRules, Part 25 – Metallic materials, 2.5. Irrespective of corro-sion protection, a corrosion addition to the net section of 2.0mm is then to be applied.

7.14.4.1.3 For standard air pipes of 760 mm height closedby heads of not more than the tabulated projected area, pipethicknesses and bracket heights are specified in Table7.14.4.1.3. Where brackets are required, three or more radialbrackets are to be fitted.

Brackets are to be of gross thickness 8 mm ormore, of minimum length 100 mm, and height according toTable 7.14.4.1.3 but need not extend over the joint flange forthe head. Bracket toes at the deck are to be suitably supported.


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7.14.4.1.4 For other configurations, loads according to7.14.3.1 are to be applied, and means of support determined inorder to comply with the requirements of 7.14.4.1.2. Brackets,where fitted, are to be of suitable thickness and length ac-cording to their height. Pipe thickness is not to be taken lessthan as indicated in the Rules, Part 8 – Pipes, 1.3.

7.14.4.1.5 For standard ventilators of 900 mm heightclosed by heads of not more than the tabulated projected area,pipe thicknesses and bracket heights are specified in Table7.14.4.1.5. Brackets, where required are to be as specified in7.14.4.1.3.

7.14.4.1.6 For ventilators of height greater than 900 mm,brackets or alternative means of support are to be fitted ac-cording to the requirements of the Rules, Part 2 - Hull. Pipethickness is not to be taken less than as indicated in the Rules,Part 8 – Pipes, 1.3.

7.14.4.1.7 All component parts and connections of the airpipe or ventilator are to be capable of withstanding the loadsdefined in 7.14.3.1

7.14.4.1.8 Rotating type mushroom ventilator heads are un-suitable for application in the areas defined in 17.4.2.

7.14.4.2 Windlass Mounts

7.14.4.2.1 Tensile axial stresses in the individual bolts ineach bolt group i are to be calculated. The horizontal forces Fxiand Fyi are normally to be reacted by shear chocks. Where

"fitted" bolts are designed to support these shear forces in oneor both directions, the von Mises equivalent stresses in the in-dividual bolts are to be calculated, and compared to the stressunder proof load. Where pour-able resins are incorporated inthe holding down arrangements, due account is to be taken inthe calculations.

The safety factor against bolt proof strength is tobe not less than 2.0.

7.14.4.2.2 The strength of above deck framing and hullstructure supporting the windlass and its securing bolt loads asdefined in 7.14.3.2 is to be according to the requirements ofthe Rules, Part 2 – Hull, 9.2.

Table 7.14.4.1.3760 mm air pipe thickness and bracket standards

Nominal pipe diameter

[mm]

Minimum fitted gross thickness, theRules, Part 8 – Pipes, 1.3

[mm]

Maximum projected area ofhead[cm2]

Height (1) of brackets

[mm]

40A(3) 6.0 - 52050A(3) 6.0 - 52065A 6.0 - 48080A 6.3 - 460100A 7.0 - 380125A 7.8 - 300150A 8.5 - 300175A 8.5 - 300200A 8.5(2) 1900 300 (2)

250A 8.5(2) 2500 300 (2)

300A 8.5(2) 3200 300 (2)

350A 8.5(2) 3800 300 (2)

400A 8.5(2) 4500 300 (2)

(1) Brackets (see 7.14.4.1.3) need not extend over the joint flange for the head.(2) Brackets are required where the as fitted (gross) thickness is less than 10.5 mm, or where the tabulated projected head area is

exceeded.(3) Not permitted for new ships - reference the Rules, Part 8 – Pipes, 1.3.Note: For other air pipe heights, the relevant requirements of section 7.14.4 are to be applied.


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Table 7.14.4.1.5900 mm ventilator pipe thickness and bracket standards

Nominal pipe diameter

[mm]

Minimum fitted gross thickness, theRules, Part 8 – Pipes, 1.3

[mm]

Maximum projected area ofhead[cm2]

Height of brackets

[mm]

80A 6.3 - 460100A 7.0 - 380150A 8.5 - 300200A 8.5 550 -250A 8.5 880 -300A 8.5 1200 -350A 8.5 2000 -400A 8.5 2700 -450A 8.5 3300 -500A 8.5 4000 -

Note: For other ventilator heights, the relevant requirements of section 7.14.4 are to be applied.

Note:Py to be examined from both inboard andoutboard directions separately - see7.14.3.2.1. The sign convention for yi isreversed when Py is from the oppositedirection as shown.

Centreline ofwindlass

Centreline of vessel

Fore

Py

H

h

Px

B

Px

Px

Figure 7.14.3.2.1Direction of forces and weight


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Figure 7.14.3.2.2Sign convention

Centreline ofwindlass

Centroid of bolt groups

Px

Py

Coordinates xi and yi are shown aseither positive (+) or negative (-).

Y3 (+)

X3 (-)

X1 (+)

Y1 (+)

X2 (+)

Y4 (+)

X4 (-)

Y2 (+)


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8 ARRAGNEMENT ANDEQUIPMENT OF SHIP'S SPACES


The requirements for the arrangement andequipment of machinery spaces are specified in the Rules,Part 7 - Machinery installation, 1.11 and 1.12, and those re-lating to refrigerating machinery spaces, refrigerant storerooms as well as refrigerated cargo spaces are set forth in theRules, Part 11 -Refrigerating plant, 3.

8.2 LOCATION OF SPACES

8.2.1 The ship's control station is to be located in anenclosed space of the wheelhouse on the navigating bridge.All navigational aids and signalling means are to be concen-trated in that place.

It is to be ensure:- proper visual control of the ship's running,- good visibility with maximum view of water

surface,- good audibility of sound signals of ap-

proaching ships.It is recommended to arrange the rudder wheel

in the ship's centre line.

8.2.2 The chart room is to be located in a space adja-cent to the wheelhouse, and a common space is to be used forboth services.

8.2.3 No accommodation spaces are to be arrangedforward of the collision bulkhead and abaft of the after peakbulkhead bellow the bulkhead deck.

8.3 EQUIPMENT OF DRY CARGOHOLDS

8.3.1 When in ships not having double bottomwooden ceiling is placed on top of the floors, it is to be solidand shall extend up to the bilge. The ceiling is recommendedto be made of portable sections of such dimensions and soconstructed as to allow of their ready removal at any place.

The thickness of a pine ceiling is to be:- at least 40 mm for ships 30 m in length and

less;- at least 60 mm for ships over 30 m in length;- at least 70 mm under cargo hatchways.

8.3.2 When in ships having double bottom woodenceiling is fitted, it is to have a thickness as follows:

- at least 50 mm for ships 60 m in length andless;

- at least 65 mm for ships over 60 m in length.The application of the ceiling made from syn-

thetic material is subject to special consideration by the Reg-ister in each case.

8.3.3 Where cargo is discharged by grabs or othermechanism, the thickness of the wooden ceiling fitted undercargo hatchways is to be doubled.

8.3.4 In holds intended for carriage of grain and otherbulk cargoes the wooden ceiling on the inner bottom, or, incase the latter is omitted, on the top of floors, is to be fitted soas to prevent wells, bilges and suction pipes of the bilgepumping from clogging.

8.3.5 The wooden ceiling is not to be laid directly onthe inner bottom, but is to be embedded in an approved bitu-minous or epoxy composition, or placed on battens along thefloors providing a clear space of 25-30 mm for drainage.

The wooden ceiling over the bilges is to beplaced so as to be readily removable.

8.3.6 The bulkheads of the deep tanks are to besheathed by wood from hold side.

8.3.7 In holds intended for the carriage of general car-goes, cargo battens made of wood or metal are to be fitted onthe sides.

The thickness of wooden battens is to be as fol-lows:

- at least 25 mm - on ships up to 20 m inlength,

- at least 40 mm - on ships up to 70 m inclu-sive,

- at least 50 mm - on ships over 70 m inlength.

The spacing between wooden battens is not toexceed 300 mm. Battens are to be attached to the side frame insuch a way as to make for easy removal and replacement. Itmay not be necessary to provided battens if Register approvesthis on the basis of the type of cargo and ship construction.

8.3.8 All projecting parts of various equipment in theholds (manholes, air pipes sounding pipes, etc.) are to be pro-tected with wooden screens, grids, chutes etc. Requirementsfor laying of piping in cargo holds are given in the Rules, Part8 – Piping, 5.5.

8.3.9 Construction of container cellular guides

8.3.9.1 For determining scantlings of substructures forcell guide systems and lashing devices the following designforces are to be used which are assumed to act simultaneouslyin the centre of gravity of stock.

- ship's transverse direction:Y = 0.5 ⋅ g ⋅ G, in [kN];

- ship's vertical direction:Z = (1 + av) ⋅ g ⋅ G, in [kN];

where:G = stack mass, in [t];av = see the Rules, Part 2 - Hull, 3.3.

8.3.9.2 The permissible stresses are to be taken as fol-lows:

normal: σ = 0.67 ReH;shear: τ = 0.45 ReH;

equivalent: σe = eHR.7703 22 =+ τσ


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8.3.10 Movable decks, platforms, ramps and othersimilar structures

8.3.10.1 The present requirements apply to the movabledecks, platforms, ramps and other similar structures designedto be installed in two positions:

- in working position when they are used forcarriage, loading or unloading of vehicles orother cargoes;

- in non-working position when they are notused for carriage, loading or unloading ofvehicles or other cargoes.

8.3.10.2 The movable decks, platforms, ramps and othersimilar structures and also their supporting elements at ship'ssides, decks and bulkheads, the pillars or suspensions fordecks and platforms ensuring their proper installation in theworking position are to be designed in accordance with theRules, Part 2 - Hull.

8.3.10.3 Arrangements are to be provided for reliable se-curing of the movable decks, platform ramps and other similarstructures in the non-working position.

8.3.10.4 When the movable decks, platforms, ramps andother similar structures are secured in the non-working posi-tion, the hoisting gear and elements thereof are not generallyto be kept under the load.

It is not permitted to secure the movable decks,platforms, ramps and other similar structures by suspendingthem on ropes.

8.3.10.5 The structural elements of the arrangementsmentioned in 8.3.10.3 and also the associated supportingstructures are to be designed to withstand the forces resultingform the application of the loads Px, Py, Pz, as obtained fromthe formulae given below, to the centres of gravity of the con-sidered section of the deck, platform, ramp or other similarstructures:

Px = m ⋅ g ⋅ ax, in [N],Py = m ⋅ g ⋅ ay, in [N],Pz = m ⋅ g ⋅ (1 + az), in [N],

where:Px = horizontal load parallel to the centre

plane of the ship, n; (consideration is tobe given to the cases when the load Px isdirected both forward and aft);

Py = horizontal load parallel to the midstationplane, in [N], (consideration is to begiven to the cases when the load Py is di-rected both to the nearest ship's side andto the opposite side);

Pz = vertical load directed downward, in [N];m = mass of the considered section, in [kg];g = 9.81 m/s2;

ax,ay,az = dimensionless accelerations, see theRules, Part 2 - Hull, 3.5.

8.3.10.6 When determining the forces affecting thestructural elements of the arrangements specified in 8.3.10.3and the associated supporting structures with regard to theprovisions of 8.3.10.5, the loads Px, Py and Pz are regarded asseparately applied i.e. no account is taken of their combinedaction and of the frictional forces originating on the surfacesof the considered sections of decks, platforms, ramps or other

similar structures which are in contact with the associatedsupporting structures.

8.3.10.7 When the structural elements of the arrange-ments specified in 8.3.10.3 and the associated supportingstructures are under the effect of the loads determined ac-cording to the provisions of 8.3.10.5 and 8.3.10.6, the stressesin their parts are not to exceed 0,7 times the upper yield stressof material.

Under the effect of these loads the safety factorof the wire ropes in relation to their actual breaking strength isnot to be less than 4; the safety factor of the chain cables inrelation to the proof load of the chain is not to be less than 2;the margin of safety against buckling of the elements sub-jected to the compression stress is not to be less than 2.

8.3.10.8 Wire ropes used in the arrangements specified in8.3.10.3 shall satisfy the Rules, Part 25 - Metallic materials, 8.

8.4 EXITS, DOORS, CORRIDORS,STAIRWAYS AND VERTICAL

LADDERS

8.4.1 General

Location and arrangement of exits, doors, corri-dors, stairways and vertical ladders shall ensure ready accessof persons from spaces to the places of embarkation into life-boats and liferafts.

8.4.2 Exits and doors

8.4.2.1 In passenger ships and in special purpose shipseach watertight compartment of similarly restricted space orgroup of spaces situated below the bulkhead deck is to have atleast two means of escape, in any case one of which is to beindependent of the door in the subdivision bulkhead.

8.4.2.2 In passenger ships and in special purpose shipsabove the bulkhead deck, each main vertical fire zone, see theRules, Part 17 - Fire protection, 2.2, or similarly restrictedspace or group of spaces shall have at least two means of es-cape one of which shall give access to a stairway forming avertical escape.

8.4.2.3 In passenger ships the number and location ofmeans of escape from special category spaces, see the Rules,Part 17 - Fire protection, 2.2, are subject to special considera-tion by the Register, and the degree of safety for escape fromthese spaces to the places of embarkation into lifeboats andliferafts shall at least correspond to that specified in 8.4.2.1and 8.4.2.2.

Two means of escape are to be provided from amachinery control room located within machinery space, atleast one which will provide continuous fire shelter to a safeposition outside the machinery space.

For cargo ships in all ro-ro cargo spaces wherethe crew is normally employed the number and locations ofescape routes to the open deck are subject to special consid-eration by the Register, but shall in no case be less than twoand are to be widely separated.

8.4.2.4 In cargo ships of 500 tons gross tonnage andupwards at each level of accommodation spaces there shall be


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at least two means of escape, as widely separated as possible,from each restricted space or group of spaces; from the spacessituated below the open deck the main means of escape are tobe formed by a stairway, the other means of escape may beformed by a casing with a vertical ladder or by a stairway.

From the spaces situated above the open deckthe means of escape are to be formed by doors of stairwaysleading to the open deck or combination thereof.

8.4.2.5 Exceptionally, the Register may dispense withone of the means of escape specified in 8.4.2.1 or 8.4.2.4, dueregard being paid to the purpose and location of spaces and tothe number of persons who normally might be quartered oremployed there.

8.4.2.6 In hydrofoil boats each passenger space is tohave at least two independent means of escape arranged at theopposite ends of the space and ensuring ready access to thelife-saving appliances.

8.4.2.7 Stairways serving only a space and a balcony inthat space, as well as lifts are not to be considered as means ofescape specified in 8.4.2.1, 8.4.2.2 to 8.4.2.4 and 8.4.2.6.

8.4.2.8 Each public room in passenger ships is to beprovided with at least two means of escape. Both exits are tobe spaced from each other as wide as practicable. A readilyseen inscription "Exit" or "Emergency exit" is to be providedabove every such exit.

8.4.2.9 The wheelhouse is to have two exits, one to eachside of the navigation bridge, with a passageway through thehouse from side to side.

8.4.2.10 The total width of exits from halls is to be de-termined on the basis of 0,8 m per 50 persons, however, thewidth of each exit is not to be less than 1,1 m, when the num-ber of seats is more than 50, and not less than 0,8 m when thenumber of seats is not more than 50.

The width of each exit from accommodation andservice spaces is not to be less than 600 mm. The size of theladderways from cargo holds is not to be less than 0,6 m.

8.4.2.11 The exit doors and ladderway covers are to be soarranged that they can be operated from both sides.

Doors shall open as follows:.1 doors of accommodation and service space

giving access to a corridor inside thespaces;

.2 doors of public rooms, outside or eachside;

.3 doors in the end bulkheads of superstruc-ture and in external transverse bulkheadsof deckhouse outside in the direction of thenearest side;

.4 doors in the external longitudinal bulkheadof deckhouses, outside in the forward di-rection.

On ships of 30 m or less in length, the doorsmentioned in .1 may open outward if they are located at theend of a blind corridor and if they do not block exits fromother spaces.

The doors discussed in .3 and .4 may also openinward, but this is subject to special consideration.

No sliding doors are permitted on exits, otherthan watertight doors on bulkheads.

8.4.2.12 Doors of accommodations are to have in theirlower portions detachable panels 0,4 x 0,5 m in size; whichmay be knocked out these panels of the passenger cabin doorsare to be provided with the following inscriptions: "Means ofescape-knock out in case of emergency".

The detachable panels need not be fitted wherethe spaces are provided with opening type side scuttles of atleast 400 mm in diameter or windows the smaller side ofwhich being at least 400 mm and on condition that personsmay get to the corridor or open deck through these side scut-tles or windows.

The appropriate means are to be provided, ifnecessary, to facilitate exit through side scuttles or windows.

8.4.3 Corridors and passageways

8.4.3.1 All corridors and passageways shall ensure freemovement of persons along them.

Vestibules, corridors or parts of corridors withonly one means of escape are not permissible for passengerships and special purpose ships having more than 50 personsof special personnel on board.

In cargo ships and special purpose ships havingless than 50 persons of special personnel on board blind corri-dors longer than 7 m are not permitted.

Blind corridor is corridor, lobby or part of corri-dor from which there is only one route of escape.

8.4.3.2 The width of main corridors in way of passen-gers and crew's accommodation spaces is not to be less than0,9 m, and that of side corridors is to be at least 0,8 m. Wherethe number of passengers and crew using the corridor sur-passes 50 persons, the widths referred to above are to be in-creased by 0,1 m.

In ships (including the tugs) below 500 tonsgross tonnage and in tugs of less than 370 kW the width of themain corridors and side corridors may be reduced down to 0,8and 0,6 m, respectively.

8.4.3.3 The width of passageways in the cinema hall andin the entrance hall is not to be less than 1,1 m and 1,4 m, re-spectively.

The width of the main passageways in the res-taurant or dining room and also the messroom is not to be lessthan 0,9 m and that of the side passageways are to be at least0,65 m. In ships of less than 500 tons gross tonnage the widthof main passageways in the messroom may be reduced downto 0,65 m.

8.4.3.4 The width of the main passageway in the seatingpassenger space is to be at least 1 m with number of passen-gers up to 50 and at least 1,1 m with number of passengers inexcess of 50.

8.4.3.5 In passenger ships the main corridors adjacent toengine and boiler casings are to be at least 1,2 m in width,however, in ships of less than 500 tons gross tonnage thiswidth may be reduced down to 0,9 m.

8.4.3.6 The width of passageway on the bridge is not tobe less than 0,8 m in ships of 500 tons gross tonnage and overand at least 0,6 m in ships of less than 500 tons gross.


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8.4.3.7 In passenger ships and special purpose ships thewidth of the deck passageways providing access to the lifeboatand liferaft embarkation deck is not to be less than:

.1 - 0,9 m if the number of seats in lifeboats isnot more than 50 on each side of ship;

.2 - 1,0 m if the number of seats in lifeboats is50 and over, but less than 100 on each sideof ship:

.3 - 1,2 m if the number of seats in lifeboats is100 and over, but less than 200 on eachside of ship.

If number of seats in lifeboats is 200 and over oneach side of ship, the width of the passageways is to be spe-cially considered by the Register in each case.

In other ships the width of the passageways re-ferred to above is not to be less than 0,8 m.

8.4.4 Stairways and vertical ladders

8.4.4.1 All between deck stairways are to be of steelframe construction or of equivalent material on agreementwith the Register. Special requirements for arrangement ofstairway enclosures and protection of means of escape arespecified in the Rules, Part 17 - Fire protection, 2.1.

In passenger ships and special purpose shipshaving more than 50 persons of special personnel on board thestairways and escape routes shall comply with following re-quirements:

.1 Stairways are not to be less than 900 mmin clear width.Stairways are to be fitted with handrails oneach side. The minimum clear width ofstairways is to be increased by 10 mm forevery one person provided for in excess of90 persons. The maximum clear widthbetween handrails where stairways arewider than 900 mm is to be 1.800 mm. Thetotal number of persons to be evacuated bysuch stairways is to be assumed to be twothirds of the crew and the total number ofpassengers in the areas served by suchstairways.

.2 All stairways sized for more than 90 per-sons are to be aligned fore and aft.

.3 Doorways and corridors and intermediatelandings included in means of escape areto be sized in the same manner as stair-ways.

.4 Stairways are not to exceed 3.5 m in verti-cal rise without the provision of a landingand are not to have an angle of inclinationgreater than 45.

.5 Landings at each deck level are not to beless than 2 m in area and are to increase by1 m for every 10 persons provided for anexcess of 20 persons but need not exceed16 m2, except for those landings servicingpublic spaces having direct access ontostairway enclosure.

8.5 GUARD RAILS, BULWARKAND GANGWAYS

8.5.1 All exposed parts of the freeboard decks, super-structure decks and deckhouse tops are to be provided with ef-ficient guard rails or bulwarks; in case of ships intended forcarriage of timber deck cargo collapsible railing or storm railsare to be fitted on this cargo.

8.5.2 The height of the bulwark or guard rails abovethe deck is not to be less than 1 m. However, where this heightwould interfere with the normal operation of the ship, a lesserheight may be approved provided the adequate protection ofpassengers and crew is ensured to the satisfaction of the Reg-ister.

8.5.3 The distance between the stanchions of theguard rails is not to be more than 1,5 m. At least every thirdstanchion is to be supported by a stay.

Removable and hinged stanchions are to be ca-pable of being locked in the upright position.

8.5.4 Hand rails and guard rails are generally to be ofrigid construction. Chains and wire ropes may be accepted inlieu of guard rails by the Register in special circumstances. Inthat case, chains and wire ropes are to be made taut by meansof turnbuckles.

8.5.5 The opening below the lowest course of theguard rails is not to exceed 230 mm. The other courses of railsare not to be more than 380 mm apart. An exception is madefor the guard rails above the timber deck cargo where theheight from the base to the lowest course and other coursespacing are not to exceed 330 mm. In the case of ships withrounded gunwale, the guard rails supports are to be placed onthe flat of the deck.

8.5.6 Type "A" ships with bulwarks as well as Type"B" ships with a freeboard reduced to that required for Type"A" ships shall have open rails fitted for at least half the lengthof the exposed parts of the weather deck, or other effectivewater freeing arrangements. The upper edge of the sheerstrake is not to be greater than 150 mm.

Where superstructures are connected by trunks,open rails are to be fitted for the whole length of the exposedparts of the freeboard deck.

8.5.7 The bulwark, if arranged, shall comply with theRules, Part 2 - Hull, 5.6.

8.5.8 Satisfactory means in the form of life lines,gangways, under deck passages, etc. are to be provided for theprotection of the crew in getting to and from their quarters, themachinery space and all other parts used in the necessary workof the ship.

The type, design and arrangement are to be spe-cially considered by the Register in each case depending onthe ship's type and freeboard height.

8.5.9 The gangway is to be designed in compliancewith the Rules, Part 2 - Hull.


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8.6 ACCESS TO THE CARGOAREA OF OIL TANKERS AND BULK

CARRIERS

Special measures are to be taken for safe accessto and working in spaces in and forward of the cargo area oftankers and bulk carriers for the purpose of maintenance andcarrying out surveys.

NOTE: This requirement is considered to be compliedwith where SOLAS, Chapter II-1, Reg. 3-6, is adhered to.

For the application of this requirement see alsoIACS Unified Interpretations (UI) SC190 (2004) andSC191(Rev. 5, May 2013).

Abstract of this Regulation is given in the fol-lowing sections:

8.6.1 Means of access and safe access to cargoholds, cargo tanks, ballast tanks and otherspaces

8.6.1.1 Means of access to cargo and other spaces

8.6.1.1.1 Each space shall be provided with a permanentmeans of access to enable, throughout the life of a ship, over-all and close-up inspections and thickness measurements ofthe ship’s structures to be carried out by the Administration,the company, as defined in regulation IX/1, and the ship’s per-sonnel and others as necessary. Such means of access shallcomply with the requirements of paragraph 8.6.3.10 to8.6.3.12 and with the Technical provisions for means of accessfor inspections, adopted by the Maritime Safety Committee byresolution MSC.133(76), as may be amended by the Organi-zation, provided that such amendments are adopted, broughtinto force and take effect in accordance with the provisions ofarticle VIII of the SOLAS Convention concerning the amend-ment procedures applicable to the Annex other than Chapter 1.

Interpretation:Each space for which close-up inspection is not

required such as fuel oil tanks and void spaces forward ofcargo area, may be provided with a means of access necessaryfor overall survey intended to report on the overall conditionsof the hull structure.

8.6.1.1.2 Where a permanent means of access may be sus-ceptible to damage during normal cargo loading and unloadingoperations or where it is impracticable to fit permanent meansof access, the Administration may allow, in lieu thereof, theprovision of movable or portable means of access, as specifiedin the Technical provisions, provided that the means of at-taching, rigging, suspending or supporting the portable meansof access forms a permanent part of the ship's structure.

All portable equipment is to be capable of beingreadily erected or deployed by ship's personnel.

8.6.1.1.3 The construction and materials of all means ofaccess and their attachment to the ship’s structure shall be tothe satisfaction of the Administration. The means of accessshall be subject to survey prior to, or in conjunction with, itsuse in carrying out surveys in accordance with regulation I/10.

8.6.1.2 Safe access to cargo holds, cargo tanks, bal-last tanks and other spaces

8.6.1.2.1 Safe access to cargo holds, cofferdams, ballasttanks, cargo tanks and other spaces in the cargo area are to bedirect from the open deck and such as to ensure their completeinspection. Safe access to double bottom spaces may be from apump-room, deep cofferdam, pipe tunnel, cargo hold, doublehull space or similar compartment not intended for the car-riage of oil or hazardous cargoes.

8.6.1.2.2 Tanks, and subdivisions of tanks, having alength of 35 m or more, are to be fitted with at least two accesshatchways and ladders, as far apart as practicable. Tanks lessthan 35 m in length are to be served by at least one accesshatchway and ladder.

When a tank is subdivided by one or more swashbulkheads or similar obstructions which do not allow readymeans of access to the other parts of the tank, at least twohatchways and ladders are to be fitted.

8.6.1.2.3 Each cargo hold is to be provided with at leasttwo means of access as far apart as practicable.

In general, these accesses are to be arranged di-agonally, for example one access near the forward bulkheadon the port side, the other one near the aft bulkhead on thestarboard side.

8.6.2 Definitions

8.6.2.1 Rung

Rung means the step of a vertical ladder or stepon the vertical surface.

8.6.2.2 Tread

Tread means the step of an inclined ladder orstep for the vertical access opening.

8.6.2.3 Flight of an inclined ladder

Flight of an inclined ladder means the actualstringer length of an inclined ladder. For vertical ladders, it isthe distance between the platforms.

8.6.2.4 Stringer

Stringer means:- the frame of a ladder; or- the stiffened horizontal plating structure

fitted on the side shell, transverse bulk-heads and/or longitudinal bulkheads in thespace.

For the purpose of ballast tanks of less than 5 mwidth forming double side spaces, the horizontal platingstructure is credited as a stringer and a longitudinal permanentmeans of access, if it provides a continuous passage of 600mm or more in width past frames or stiffeners on the side shellor longitudinal bulkhead. Openings in stringer plating utilisedas permanent means of access are to be arranged with guardrails or grid covers to provide safe passage on the stringer orsafe access to each transverse web.


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8.6.2.5 Vertical ladder

Vertical ladder means a ladder of which the in-clined angle is 70º and over up to 90º. A vertical ladder is notto be skewed by more than 2º.

8.6.2.6 Overhead obstructions

Overhead obstructions mean the deck or stringerstructure including stiffeners above the means of access.

8.6.2.7 Distance below deck head

Distance below deck head means the distancebelow the plating.

8.6.2.8 Cross deck

Cross deck means the transverse area of themain deck which is located inboard and between hatch coam-ings.

8.6.3 Technical provisions

8.6.3.1 Structural members subject to the close-up in-spections and thickness measurements of the ship's structure,except those in double bottom spaces, are to be provided witha permanent means of access to the extent as specified in Ta-ble 8.6.3.1 and Table 8.6.3.2, as applicable. For oil tankers andwing ballast tanks of ore carriers, approved alternative meth-ods may be used in combination with the fitted permanentmeans of access, provided that the structure allows for its safeand effective use.

8.6.3.2 Permanent means of access should as far as pos-sible be integral to the structure of the ships, thus ensuring thatthey are robust and at the same time contributing to the overallstrength of the structure of the ship.

8.6.3.3 Elevated passageways forming sections of apermanent means of access, where fitted, are to have a mini-mum clear width of 600 mm, except for going around verticalwebs where the minimum clear width may be reduced to 450mm, and have guard rails over the open side of their entirelength. Sloping structures providing part of the access are tobe of a non-skid construction. Guard rails are to be 1,000 mmin height and consist of a rail and an intermediate bar 500 mmin height and of substantial construction. Stanchions are to benot more than 3 m apart.

8.6.3.4 Access to permanent means of access and verti-cal openings from the ship's bottom are to be provided bymeans of easily accessible passageways, ladders or treads.Treads are to be provided with lateral support for the foot.Where the rungs of ladders are fitted against a vertical surface,the distance from the centre of the rungs to the surface is to beat least 150 mm. Where vertical manholes are fitted higherthan 600 mm above the walking level, access is to be facili-tated by means of treads and hand grips with platform land-ings on both sides.

8.6.3.5 Permanent inclined ladders are to be inclined atan angle of less than 70º. There shall be no obstructions within750 mm of the face of the inclined ladder, except that in wayof an opening this clearance may be reduced to 600 mm.Resting platforms of adequate dimensions are to be provided,normally at a maximum of 6 m vertical height. Ladders andhandrails are to be constructed of steel or equivalent material

of adequate strength and stiffness and securely attached to thestructure by stays. The method of support and length of stay isto be such that vibration is reduced to a practical minimum. Incargo holds, ladders are to be designed and arranged so thatcargo handling difficulties are not increased and the risk ofdamage from cargo handling gear is minimised.

8.6.3.6 The width of inclined ladders between stringersis not to be less than 400 mm. The treads are to be equallyspaced at a distance apart, measured vertically, of between 200mm and 300 mm. When steel is used, the treads are to beformed of two square bars of not less than 22 mm by 22 mmin section, fitted to form a horizontal step with the edgespointing upward.

The treads are to be carried through the sidestringers and attached thereto by double continuous welding.All inclined ladders are to be provided with handrails of sub-stantial construction on both sides, fitted at a convenient dis-tance above the treads.

8.6.3.7 For vertical ladders or spiral ladders, the widthand construction are to be in accordance with international ornational standards accepted by the Administration.

8.6.3.8 No free-standing portable ladder is to be morethan 5 m long.

8.6.3.9 Alternative means of access include, but are notlimited to, such devices as:

– hydraulic arm fitted with a stable base– wire lift platform– staging– rafting– root arm or remotely operated vehicle

(ROV)– portable ladders more than 5 m long are

only to be utilised if fitted with a mechani-cal device to secure the upper end of theladder

– other means of access, approved by andacceptable to the Administration.

Means for safe operation and rigging of suchequipment to and from and within the spaces are to be clearlydescribed in the Ship Structure Access Manual.

8.6.3.10 For access through horizontal openings, hatchesor manholes, the minimum clear opening is not to be less than600 mm x 600 mm. When access to a cargo hold is arrangedthrough the cargo hatch, the top of the ladder is to be placed asclose as possible to the hatch coaming. Access hatch coamingshaving a height greater than 900 mm is to also have steps onthe outside in conjunction with the ladder.

8.6.3.11 For access through vertical openings, or man-holes, in swash bulkheads, floors, girders and web frames pro-viding passage through the length and breadth of the space, theminimum opening is not to be less than 600 mm x 800 mm ata height of not more than 600 mm from the passage unlessgratings or other foot holds are provided.

8.6.3.12 For oil tankers of less than 5000 tonnes dead-weight, the Administration may approve, in special circum-stances, smaller dimensions for the openings referred to in8.6.3.10 and 8.6.3.11, if the ability to traverse such openingsor to remove an injured person can be proved to the satisfac-tion of the Administration.


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8.6.3.13 For bulk carriers, access ladders to cargo holdsand other spaces are to be:

8.6.3.13.1 Where the vertical distance between the uppersurface of adjacent decks or between deck and the bottom ofthe cargo space is not more than 6 m, either a vertical ladderor an inclined ladder.

8.6.3.13.2 Where the vertical distance between the uppersurface of adjacent decks or between deck and the bottom ofthe cargo space is more than 6 m, an inclined ladder or seriesof inclined ladders at one end of the cargo hold, except the up-permost 2,5 m of a cargo space measured clear of overheadobstructions and the lowest 6 m may have vertical ladders,provided that the vertical extent of the inclined ladder or lad-ders connecting the vertical ladders is not less than 2,5 m.

The second means of access at the other end ofthe cargo hold may be formed of a series of staggered verticalladders, which should comprise of one or more ladder linkingplatforms spaced not more than 6 m apart vertically and dis-placed to one side of the ladder. Adjacent sections of ladderare to be laterally offset from each other by at least the widthof the ladder. The uppermost entrance section of the ladder di-rectly exposed to a cargo hold is to be vertical for a distance of2,5 m measured clear of overhead obstructions and connectedto a ladder-linking platform.

8.6.3.13.3 A vertical ladder may be used as a means of ac-cess to topside tanks, where the vertical distance is 6 m or lessbetween the deck and the longitudinal means of access in thetank or the stringer or the bottom of the space immediatelybelow the entrance. The uppermost entrance section from deckof the vertical ladder of the tank is to be vertical for a distanceof 2,5 m measured clear of overhead obstructions and com-prise a ladder linking platform, unless landing on the longitu-dinal means of access, the stringer or the bottom within thevertical distance, displaced to one side of a vertical ladder.

8.6.3.13.4 Unless allowed in 8.6.3.13.3 above, an inclinedladder or combination of ladders is to be used for access to atank or a space where the vertical distance is greater than 6 mbetween the deck and a stringer immediately below the en-trance, between stringers, or between the deck or a stringerand the bottom of the space immediately below the entrance.

8.6.3.13.5 In case of 8.6.3.13.4 above, the uppermost en-trance section from deck of the ladder is to be vertical for adistance of 2,5 m clear of overhead obstructions and con-nected to a landing platform and continued with an inclinedladder.

The flights of inclined ladders are not to be morethan 9 m in actual length and the vertical height is not nor-mally to be more than 6 m. The lowermost section of the lad-ders may be vertical for a distance of not less than 2,5 m.

8.6.3.13.6 In double-side skin spaces of less than 2,5 mwidth, the access to the space may be by means of verticalladders that comprise of one or more ladderlinking platformsspaced not more than 6 m apart vertically and displaced to oneside of the ladder.

Adjacent sections of ladder are to be laterally offset from eachother by at least the width of the ladder.

8.6.3.13.7 A spiral ladder is considered acceptable as analternative for inclined ladders. In this regard, the uppermost

2,5 m can continue to be comprised of the spiral ladder andneed not change over to vertical ladders.

8.6.3.13.8 The uppermost entrance section from deck of thevertical ladder providing access to a tank is to be vertical for adistance of 2,5 m measured clear of overhead obstructions andcomprise a ladder linking platform, displaced to one side of avertical ladder.

The vertical ladder can be between 1,6 m and 3m below deck structure if it lands on a longitudinal or athwart-ship permanent means of access fitted within that range.

8.6.4 Ship structure access manual

8.6.4.1 A ship's means of access to carry out overall andclose-up inspections and thickness measurements are to be de-scribed in a Ship structure access manual approved by theAdministration, an updated copy of which is to be kept onboard. The Ship structure access manual shall include the fol-lowing for each space in the cargo area:

– plans showing the means of access to thespace, with appropriate technical specifi-cations and dimensions,

– plans showing the means of access withineach space to enable an overall inspectionto be carried out, with appropriate techni-cal specifications and dimensions. Theplans shall indicate from where each areain the space can be inspected.

– plans showing the means of access withinthe space to enable close-up inspections tobe carried out, with appropriate technicalspecifications and dimensions. The plansshall indicate the positions of criticalstructural areas, whether the means of ac-cess is permanent or portable and fromwhere each area can be inspected.

– instructions for inspecting and maintainingthe structural strength of all means of ac-cess and means of attachment, taking intoaccount any corrosive atmosphere thatmay be within the space,

– instructions for safety guidance whenrafting is used for close-up inspections andthickness measurements,

– instructions for the rigging and use of anyportable means of access in a safe manner,

– an inventory of all portable means of ac-cess,

– records of periodical inspections andmaintenance of the ship's means of access.

8.6.4.2 For the purpose of these regulations "criticalstructural areas" are locations which have been identified fromcalculations to require monitoring or from the service historyof similar or sister ships to be sensitive to cracking, buckling,deformation or corrosion which would impair the structuralintegrity of the ship.

8.6.4.3 It is recommended that IACS Rec. 90 and 91 betaken into account when compiling the Ship structure accessmanual described in Section 8.6.4.


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8.6.5 Safe access to tanker bows

8.6.5.1 Every tanker is to be provided with the means toenable the crew to gain safe access to the bow even in severeweather conditions.

8.6.5.2 For the purpose of this regulation, tankers in-clude oil tankers as defined in SOLAS, Chapter II-1, Reg.2,chemical tankers as defined in regulation VII/8.2 and gas car-riers as defined in regulation VII/11.2.

8.6.5.3 Such means of access are to be in accordancewith the requirements of guidelines for safe access to tankerbow (Res. MSC. 62(67)) and are to be approved by the Regis-ter. Interpretation of SOLAS II-1/3-3.2, Safe access to tankerbows, for all vessels subject to that regulation, is provided inIACS unified interpretations SC 138 and LL 50.

Table 8.6.3.1 Means of access for ballast and cargo tanks of oil tankers

1. Water ballast tanks except those specified in the rightcolumn, and cargo oil tanks

2. Water ballast wing tanks of less than 5 m widthforming double side spaces and their bilge hopper sec-tions

Access to the underdeck and vertical structure

1.1 For tanks of which the height is 6 m and over containinginternal structures, permanent means of access are to beprovided in accordance with .1 to .6:

.1 continuous athwartship permanent access arrangedat each transverse bulkhead on the stiffened sur-face, at a minimum of 1.6 m to a maximum of 3 mbelow the deck head;

.2 at least one continuous longitudinal permanentmeans of access at each side of the tank. One ofthese accesses is to be at a minimum of 1.6 m to amaximum of 6 m below the deck head and the otheris to be at a minimum of 1.6 m to a maximum of 3m below the deck head;

.3 access between the arrangements specified in .1 and.2 and from the main deck to either .1 or .2;

.4 continuous longitudinal permanent means of accesswhich are integrated in the structural member onthe stiffened surface of a longitudinal bulkhead, inalignment, where possible, with horizontal girdersof transverse bulkheads are to be provided for ac-cess to the transverse webs unless permanent fit-tings are installed at the uppermost platform for useof alternative means, as defined in paragraph8.6.3.9 of the Technical provisions, for inspectionat intermediate heights;

.5 for ships having cross-ties which are 6 m or moreabove tank bottom, a transverse permanent meansof access on the cross-ties providing inspection ofthe tie flaring brackets at both sides of the tank,with access from one of the longitudinal permanentmeans of access in .4; and

.6 alternative means as defined in paragraph 8.6.3.9 ofthe Technical provisions may be provided for smallships as an alternative to .4 for cargo oil tanks ofwhich the height is less than 17 m.

2.1 For double side spaces above the upper knuckle point ofthe bilge hopper sections, permanent means of access areto be provided in accordance with .1 to .3:

.1 the vertical distance between horizontal uppermoststringer and deck head is 6 m or more, one continu-ous longitudinal permanent means of access is to beprovided for the full length of the tank with a meansto allow passing through transverse webs installed ata minimum of 1.6 m to a maximum of 3 m below thedeck head with a vertical access ladder at each end ofthe tank;

.2 continuous longitudinal permanent means of access,which are integrated in the structure, at a verticaldistance not exceeding 6 m apart; and

.3 plated stringers are, as far as possible, to be in align-ment with horizontal girders of transverse bulkheads.


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1.2 For tanks of which the height is less than 6 m, alterna-tive means as defined in paragraph 8.6.3.9 of the Tech-nical provisions or portable means may be utilised inlieu of the permanent means of access.

2.2 For bilge hopper sections of which the vertical distancefrom the tank bottom to the upper knuckle point is 6 mand over, one longitudinal permanent means of access isto be provided for the full length of the tank. It is to beaccessible by vertical permanent means of access ateach end of the tank.

2.2.1 The longitudinal continuous permanent meansof access may be installed at a minimum 1.6 mto maximum 3 m from the top of the bilge hop-per section. In this case, a platform extendingthe longitudinal continuous permanent means ofaccess in way of the webframe may be used toaccess the identified structural critical areas.

2.2.2 Alternatively, the continuous longitudinal per-manent means of access may be installed at aminimum of 1.2 m below the top of the clearopening of the web ring allowing a use of port-able means of access to reach identified struc-tural critical areas.

Fore peak tanks

1.3 For fore peak tanks with a depth of 6 m or more at thecentre line of the collision bulkhead, a suitable means ofaccess are to be provided for access to critical areas suchas the underdeck structure, stringers, collision bulkheadand side shell structure.

1.3.1 Stringers of less than 6 m in vertical distancefrom the deck head or a stringer immediatelyabove are considered to provide suitable accessin combination with portable means of access.

1.3.2 In case the vertical distance between the deckhead and stringers, stringers or the loweststringer and the tank bottom is 6 m or more, al-ternative means of access as defined in para-graph 3.9 of the Technical provisions are to beprovided.

2.3 Where the vertical distance referred to in 2.2 is less than6 m, alternative means as defined in paragraph 3.9 of theTechnical provisions or portable means of access maybe utilised in lieu of the permanent means of access. Tofacilitate the operation of the alternative means of ac-cess, in-line openings in horizontal stringers are to beprovided.

The openings are to be of an adequate diameter and areto have suitable protective railings.


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Table 8.6.3.2Means of access for bulk carriers 1)

1. Cargo holds 2. Ballast tanks

Access to the underdeck structure

1.1 Permanent means of access are to be fitted to provideaccess to the overhead structure at both sides of thecross deck and in the vicinity of the centreline.

Each means of access are to be accessible from thecargo hold access or directly from the main deck and in-stalled at a minimum of 1.6 m to a maximum of 3 mbelow the deck.

1.2 An athwartship permanent means of access fitted on thetransverse bulkhead at a minimum 1.6 m to a maximum3 m below the cross-deck head is accepted as equivalentto 1.1.

1.3 Access to the permanent means of access to overheadstructure of the cross deck may also be via the upperstool.

1.4 Ships having transverse bulkheads with full upper stoolswith access from the main deck which allows monitor-ing of all framing and plates from inside do not requirepermanent means of access of the cross deck.

1.5 Alternatively, movable means of access may be utilisedfor access to the overhead structure of the cross deck ifits vertical distance is 17 m or less above the tank top.

Top side tanks

2.1 For each topside tank of which the height is 6 m andover, one longitudinal continuous permanent means ofaccess are to be provided along the side shell webs andinstalled at a minimum of 1.6 m to a maximum of 3 mbelow deck with a vertical access ladder in the vicinityof each access to that tank.

2.2 If no access holes are provided through the transversewebs within 600 mm of the tank base and the web framerings have a web height greater than 1 m in way of sideshell and sloping plating, then step rungs/grab rails areto be provided to allow safe access over each transverseweb frame ring.

2.3 Three permanent means of access, fitted at the end bayand middle bay of each tank, are to be provided span-ning from tank base up to the intersection of the slopingplate with the hatch side girder. The existing longitudi-nal structure, if fitted on the sloping plate in the spacemay be used as part of this means of access.

2.4 For topside tanks of which the height is less than 6 m,alternative means as defined in paragraph 8.6.3.9 of theTechnical provisions or portable means may be utilisedin lieu of the permanent means of access.

Access to the vertical structure

1.6 Permanent means of vertical access are to be providedin all cargo holds and built into the structure to allow foran inspection of a minimum of 25 % of the total numberof hold frames port and starboard equally distributedthroughout the hold including at each end in way oftransverse bulkheads. But in no circumstance shall thisarrangement be less than 3 permanent means of verticalaccess fitted to each side (fore and aft ends of hold andmid-span).

Permanent means of vertical access fitted between twoadjacent hold frames is counted for an access for the in-spection of both hold frames. A means of portable ac-cess may be used to gain access over the sloping platingof lower hopper ballast tanks.

1.7 In addition, portable or movable means of access are tobe utilised for access to the remaining hold frames up totheir upper brackets and transverse bulkheads.

1.8 Portable or movable means of access may be utilised foraccess to hold frames up to their upper bracket in placeof the permanent means required in 1.6. These means ofaccess are to be carried on board the ship and readilyavailable for use.

1.9 The width of vertical ladders for access to hold frames isto be at least 300 mm, measured between stringers.

Bilge hopper tanks

2.5 For each bilge hopper tank of which the height is 6 mand over, one longitudinal continuous permanent meansof access are to be provided along the side shell websand installed at a minimum of 1.2 m below the top ofthe clear opening of the web ring with a vertical accessladder in the vicinity of each access to the tank.

2.5.1 An access ladder between the longitudinal con-tinuous permanent means of access and the bot-tom of the space is to be provided at each end ofthe tank.

2.5.2 Alternatively, the longitudinal continuous per-manent means of access can be located throughthe upper web plating above the clear opening ofthe web ring, at a minimum of 1.6 m below thedeck head, when this arrangement facilitatesmore suitable inspection of identified structur-ally critical areas. An enlarged longitudinalframe can be used for the purpose of the walk-way.

For double-side skin bulk carriers, the longitudi-nal continuous permanent means of access maybe installed within 6 m from the knuckle pointof the bilge, if used in combination with alterna-tive methods to gain access to the knuckle point.

2.6 If no access holes are provided through the transversering webs within 600 mm of the tank base and the webframe rings have a web height greater than 1 m in wayof side shell and sloping plating, then step rungs/grabrails are to be provided to allow safe access over eachtransverse web frame ring.


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1.10 A single vertical ladder over 6 m in length is acceptablefor the inspection of the hold side frames in a single skinconstruction.

1.11 For double-side skin construction no vertical ladders forthe inspection of the cargo hold surfaces are required.Inspection of this structure is to be provided from withinthe double hull space.

2.7 For bilge hopper tanks of which the height is less than 6m, alternative means as defined in paragraph 8.6.3.9 ofthe Technical provisions or portable means may be util-ised in lieu of the permanent means of access. Suchmeans of access are to be demonstrated that they can bedeployed and made readily available in the areas whereneeded.

Double-skin side tanks

2.8 Permanent means of access are to be provided in accor-dance with the applicable sections of Table 8.6.3.1.

Fore peak tanks

2.9 For fore peak tanks with a depth of 6 m or more at thecentreline of the collision bulkhead, a suitable means ofaccess are to be provided for access to critical areas suchas the underdeck structure, stringers, collision bulkheadand side shell structure.

2.9.1 Stringers of less than 6 m in vertical distancefrom the deck head or a stringer immediatelyabove are considered to provide suitable accessin combination with portable means of access.

2.9.2 In case the vertical distance between the deckhead and stringers, stringers or the loweststringer and the tank bottom is 6 m or more, al-ternative means of access as defined in para-graph 8.6.3.9 of the Technical provisions are tobe provided.

Note:1) For ore carriers, permanent means of access are to be provided in accordance with the applicable sections of Table 8.6.3.1 and

Table 8.6.3.2.

Rules for the classification of ships, Part 3, 2013 - crs.hr for the... · RULES FOR THE CLASSIFICATION OF SHIPS Part 3 ... draught to be assigned to the ship, see the Rules, Part

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