Mooring of ships - forces

Mooring of ship - TVS 1ste kan

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Mooring of ships - forces

Kapt. K. De Baere


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Purpose of mooring configuration To bring the ship alongside To keep the ship alongside To assist the ship when un-mooring


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Design criteria of mooring configurations Based on the forces acting upon the ship

Wind Current Waves Swell Other ships passing by (suction effect) Location of the berth – Protected or sea berth Types of ship – size, displacement, draught

etc.


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Protected berths Design criteria – limiting valuesDesign criteria – limiting values

Cross wind up till 15m/sec (6-7 Beaufort)Cross wind up till 15m/sec (6-7 Beaufort) Tidal current of 3 knots in longitudinal Tidal current of 3 knots in longitudinal

directiondirection Cross current of 1 knotCross current of 1 knot

Cargo- and container ship are normally Cargo- and container ship are normally moored along well protected berths => moored along well protected berths => Mooring winches are designed to pull the Mooring winches are designed to pull the ship alongside with 1 headline and 1 stern ship alongside with 1 headline and 1 stern line against a cross wind of 5 Beaufortline against a cross wind of 5 Beaufort


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Sea berths – designed for >wind

Design criteria – limiting valuesDesign criteria – limiting values Cross winds up till 20m/sec or 8 Cross winds up till 20m/sec or 8

Beaufort and gust of winds up till Beaufort and gust of winds up till 10 Beaufort10 Beaufort

Tidal current of 3 knots in Tidal current of 3 knots in longitudinal directionlongitudinal direction

Cross current of 1 knotCross current of 1 knot Waves and swellWaves and swell

Waves and swell with a short period Waves and swell with a short period have a limited influencehave a limited influence


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Fetch The The size of a wave depends on its size of a wave depends on its

fetch. The fetch is the distance a fetch. The fetch is the distance a wave travelswave travels (see next slide) (see next slide). The . The greater the fetch, the larger the greater the fetch, the larger the wave. wave.

If the wind is blowing for a longer If the wind is blowing for a longer period of time in the same direction period of time in the same direction => long fetch with a high wave => long fetch with a high wave height and a longer period => height and a longer period => important dynamic effect on the shipimportant dynamic effect on the ship


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Fetch – DefinitionGrowth rate of wind generated waves

The distance that wind and seas The distance that wind and seas (waves) can travel (waves) can travel toward landtoward land without being blockedwithout being blocked. In areas . In areas without obstructions the wind without obstructions the wind and seas can build to great and seas can build to great strength, but in areas such as strength, but in areas such as sheltered coves and harbours sheltered coves and harbours the wind and seas will be the wind and seas will be calmer. calmer.


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Mooring of VLCC’s Often moored outside the harbours along

sea berths Forces are so great that no winch is

capable of bringing the ship alongside Tugs are always used when mooring and

leaving berth The only criteria is the holding force of the

winches The ship must be maintained in position

related to the shore manifold (chiksans)


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Relation maximum pulling power – Displacement () Figures are used to design shore

facilities (bollards, bits ……….. Etc.) 25% safety margin to be added

8000 ton – 100 kN8000 ton – 100 kN 10.000 ton – 300 kN10.000 ton – 300 kN

20.000 ton – 600 kN20.000 ton – 600 kN 50.000 ton – 600 kN50.000 ton – 600 kN

100.000 ton – 1000 kN100.000 ton – 1000 kN 200.000 ton – 1500 kN200.000 ton – 1500 kN

1 kN = 1 ton pulling power (not scientific)


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Mooring winch with undivided drum


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Mooring winches – Divided drum-polyprop octopus


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Chicksan


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Chicksan One of the biggest One of the biggest

problems with the problems with the fixed fixed loading/discharging loading/discharging systems is the systems is the restricted liberty of restricted liberty of movement of the movement of the shipship

If one of the limits is If one of the limits is breached => breached => EESD-SD-system activatedsystem activated


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Assessing the forces1. Forces due to wind and current are proportional

to the square of their speeds. f.i. the force caused by a wind of 40 knots is 4 times the influence of a wind of 20 knots

2. The wind speed increases with the height above the ground. A wind of 10 knots at 2 meters increases till 60 knots at 40 meters => importance of the freeboard (height of the structure). To obtain comparable figures all winds are recalculated to a standard height of 10 meters


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Maximum wind limits (400.000 dwt ship) in Maximum wind limits (400.000 dwt ship) in function of the breaking power of the function of the breaking power of the wincheswinches


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Wind limits The previous pictures learns us

that;1. The wind limit is determined by the

holding power (breaking power) of the winches

2. The wind limit is determined by the material of the mooring lines


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Assessing the forces3. Influence of a cross current is inverse

proportional with the keel clearance. In case of a small keel clearance the current is obstructed by the ships hull and searches way out via the stem and the stern. A Suction effect is created trying the move the ship away from the berth.


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TheoreticalTheoretical example of the influence example of the influence of the keel clearanceof the keel clearance

A ULCC with a draft of 15 meters is moored alongside a berth with 16.5 meters of water => relation water depth/draft = 1.1

Relative resistance factor in case of cross current = 5.6

In case of unlimited water depth a cross current of 1 knot produces a force of 60 tons


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In case of a limited water depth (example) this force is increased till 5.6 x 60 ton = 336 ton

This equals 9 steel mooring ropes of 40mm diameter


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The relative proportion of the different elements has to be considered

Ballasting decreases the keel clearance but also reduces the lateral wind surface. The wind effect is of greater importance than the the clearance effect (see next slide).


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Example of cross and longitudinal forces

18.000 & 70.000 SDWT: Wind 60 knots (30m/s), current 5 knots longitudinal and 1 knot cross current

200.000 SDWT: Wind 60 knots, current 3 knots longitudinal and 1 knot cross current


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Conclusions In ballast condition the most important In ballast condition the most important

forces are wind generatedforces are wind generated In loaded condition the most important In loaded condition the most important

forces are current generatedforces are current generated The total force on the ship (alongships + The total force on the ship (alongships +

athwartships) is greater in ballast athwartships) is greater in ballast condition than in loaded condition => condition than in loaded condition => influence of the wind is of greater influence of the wind is of greater importanceimportance


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Different materials 3 different configurations

All steel wire ropes (equipped or not equipped with tails)

All ropes are synthetic Mixed systems (synthetic + steel wire

rope) New materials


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Steel wire rope + tail (ralonge de la touline) Purpose of the tail is to add elasticity to

account for change in tidal heights Always use 8 strands nylon with an MBL

25% > steel wire rope To protect against chafing cover splice of

the tail with leather or plastic The tail is connected to the steel wire

rope by means of a Tonsberg shackle or a Mandal shackle

In case of frequent use tails are changed every 18 months


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Steel wire rope + tail Steel wire rope have a high MBL and are

not elastic. Steel wire rope are stored on winch drums

with a manual brake Steel wire rope are relatively easy to

handle up to 40mm ???? Steel wire ropes last longer than synthetic

ropes Price steel wire = synthetic


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Tonsberg shackles


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Mandal Shackle


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Full synthetic mooring configuration Biggest problem is elasticity This elasticity can give an important

« sway » (balancer) to the ship (breaking out)

3 mooring ropes – different materials – same length (50 m), MBL and load Steel wire – 0.3m elongation Polyprop – 5m elongation Nylon – 8 m elongation


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Breaking out


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Effect of the hawser elasticity on the restraint capacity

1. Materials with the smallest elasticity take the biggest load

2. Short rope = big load

3. Relation - is not linear


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Full synthetic mooring configuration

SSynthetic fibres loose ynthetic fibres loose tensile strength (force tensile strength (force de traction) if de traction) if submitted to cyclic submitted to cyclic tensions attaining 30 to tensions attaining 30 to 50% of their MBL. 50% of their MBL.

Those cyclic tensions Those cyclic tensions are not constant, due are not constant, due to resonance high to resonance high tensions occure during tensions occure during short periods of timeshort periods of time


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Full synthetic mooring configuration Because of;

Cyclic tensions Internal friction Exposure to the marine environment

Tensile strength of synthetic ropes will diminish after 1 year

Tensile strength of steel wire rope will diminish after 5 years => more durable


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Full synthetic mooring configuration

Another side effect Another side effect is sagging is sagging (affaissement)(affaissement)

The « sag » is The « sag » is function of;function of; m-nm-n Weight of the Weight of the

mooring linemooring line Tension in the lineTension in the line Water depthWater depth (suction (suction

effect)effect)


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Full synthetic mooring configuration Consequence of the sagging is that a

synthetic rope can never be pulled as stiff as a wire rope.

A wire rope will « react » faster on a breaking out of the ship.

A synthetic rope will compensate the the sag before reacting

Max. allowed distance between berth and ship is normally limited to 6% of the water depth


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Mixed mooring systems Mix of wire ropes and synthetic

ropes Certainly NOT the best configuration

but the most common one. If possible use steel wire rope as

springs and breasts and use synthetic ropes as head- and stern line


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New materials Composite materials Expensive but excellent mooring

system Kevlar –Aramid ropes are very

strong, light and show little sagging. They react fast in case of breaking out of the ship.


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Efficient mooring The efficiency of a mooring rope The efficiency of a mooring rope

depends on the following factorsdepends on the following factors Material (steel wire or synthetic – Material (steel wire or synthetic –

elongation & MBL)elongation & MBL) LengthLength Angles with longitudinal and transversal Angles with longitudinal and transversal

axis in the horizontal planeaxis in the horizontal plane Angles with the horizontal in the vertical Angles with the horizontal in the vertical

planeplane


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Function of the different ropes Head- and stern lines & the springs are

stabilising the ship alongside Breast line will prevent the ship to break

free from the berth Breast lines must be as perpendicular as

possible to the ships longitudinal axis Springs must be as parallel as possible to

the berth


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Recommendations The function of springs and breast lines is

clear. Springs are preventing longitudinal movement while breast are opposing transversal movements.

The function of head and the stern lines depends on their angle with the longitudinal axis. Great angle => they serve mainly as breast line while small angle => stopping longitudinal movement


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Recommendations The ideal configuration will rarely be

achieved. To obtain a perfect mooring configuration

their must be a perfect harmony between the ships equipment and disposition on board and the configuration ashore

Berthing ships is always a matter of compromises


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Recommendations Following recommendations have

been published by the OCIMF = Oil Company International Maritime Forum

The recommendations are valid for a tanker moored alongside a T-berth


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Recommendations based on OCIMF – Effective mooring

1. The horizontal angles of head-, stern- and breast lines < 15°


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Recommendations based on OCIMF – Effective mooring2. The vertical angle with the horizontal

plane must be < 25° The effective force is proportional to the

cosine of the angle If the angle is 25° the line is effective for

91% If the angle is 45° the efficiency is reduced

to 71% => Springs & breasts must be long

enough and not to steep


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Springs & Breasts


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3. Breast lines are most effective is on the longitudinal axis.

If is 45° we have to increase the force in the breast line till 141 ton to obtain an effective transversal force of 100 ton


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4. Springs offer the greatest holding power in the longitudinal direction. Their length is 60 meters


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5. The impact of the head and the stern lines on the total holding power of the mooring configuration is less important than the influence of springs and breasts. This mainly because these lines are too long.

Never the less they are important to compensate the dynamical forces.

Length 110m = ½ coil


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6. Very short lines must be avoided. They always take the most important part of the load, especially when the ship is moving

Short length = important vertical angle


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Short breast lines

Long breast line: 52ton load is sufficient to Long breast line: 52ton load is sufficient to obtain an effective holding power of 50 tonobtain an effective holding power of 50 ton

Short breast line: Load has to be increased Short breast line: Load has to be increased till 88 ton to obtain same resulttill 88 ton to obtain same result


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7. All the mooring ropes in the same group (working in the same direction)must have a same tension. If not, the weakest line will break first. Total load will have to be received by the remaining lines => increased risk of breaking (chain reaction)

Groups are f.i. aft spring + head lines, Stern lines + forward spring, breast lines


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8. Their must be an equilibrium between the 4 groups (head- and stern lines, springs and breasts.

Example: Optimal mooring configuration is determined after studying the static and dynamical forces for a specific berth.


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Mooring example Maximum breaking out from the berth = 1

meter Direction of the wind: 110° -> 290° Frequency 58% 25.2% 3 à 4 Beaufort 0.65% > 8 Beaufort Proposed configuration all nylon 80mm

(MBL 110 ton): 4 breast lines (aft) + 1 stern line 3 headlines + 3 breast lines (fore)

The fore ship will resist a wind pressure of 32 knots The fore ship will resist a wind pressure of 32 knots while the stern will resist a wind pressure of 33 while the stern will resist a wind pressure of 33 knots => The berth will be operational till 7 knots => The berth will be operational till 7 Beaufort => not operational 5.8% per yearBeaufort => not operational 5.8% per year

The configuration of the berth is not ideal since the The configuration of the berth is not ideal since the horizontal angles > 15°horizontal angles > 15°


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9. The number of lines is function of the size of the ship and the prevailing weather conditionsA – Panamax (75.000 dwt) - 12 lines (2 headlines – 4 breasts – 4 springs – 2 stern lines: 2 –2 – 2 fore and aft)B – VLCC (150.000 dwt) 16 lines (4 headlines – 4 breasts – 4 springs – 4 stern lines: 4 –2 – 2 fore and aft)


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A – Panamax & B - VLCC


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Mooring configurations bulk carriers

Cape Size: 4 –2 – 2 (fore and aft) Panamamax: 4 –1– 1 (fore and aft) Handy Size: 4 –1 (fore and aft) Mini Bulker: 3 –1 (fore and aft) Mini Bulker – moored so it can shift

forward and backwards during loading/discharging


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Mooring configurations bulk carriers


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10. Mooring lines must be passed ashore using the deck fittings (fairleads) because of friction and the curvature relation.Curvature relation = curvature deck fitting/ mooring lineIn case of a mooring wire relation has to be > 20 to reduce loss in tensile strength


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Mooring configuration –concentrated on the fore ship


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Deck fittings(accessoires de pont)

OCIMF equipment:Panamahawse- hole Pedestal Fairleads (Chaumard)


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Info

Suez & Panama Canal


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Suez Canal Total length is 190.25 km Water surface width is 280.345 m Width between the buoys is 195.215 m Canal depth is 22.5 m Maximum ship draught allowed is 62ft Speed allowed for loaded carriers is 13 km/h Speed allowed for unloaded carriers is 14

km/h. Average transit time is 14 hours

Suez Canal


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Panama Canal The Panama Canal is approximately 80

kilometers. The Canal uses a system of locks The locks function as water lifts: they raise

ships from sea level (the Pacific or the Atlantic) to the level of Gatun Lake (26 meters above sea level)


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Panama Canal Each set of locks bears the name of the

townsite where it was built: Gatun (on the Atlantic side), and Pedro Miguel and Miraflores (on the Pacific side).

The maximum dimensions of ships that can transit the Canal are: 32.3 meters in beam; draft 12 meters in Tropical Fresh Water; and 294.1 meters long

The narrowest portion of the Canal is Culebra Cut


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Panama Canal


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Gatun Lock

Gaillard Cut


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Pedro Miguel Locks


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Mira Flores Locks

4-roller fear lead Towing Bracket


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Smit Towing Bracket


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Chocks and buttons


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Bits and Bollards


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Panama chocks


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Roller Chocks


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Roller Fairleads


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Towing pads (point d’attache pour le câble de remorque)


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Emergency Towing Systems SOLAS Requirement Regulation Chapter II-1, A-1, 3-4 Since 1996, January 1, all tankers exceeding,

20,000 DWT are to have an emergency towing arrangement fitted at the aft and forward. This IMO resolution MSC35(63) which covers the installation of emergency towing arrangements on tankers was decreed after the unfortunate disaster of the MV Braer in 1993.


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Emergency Towing Systems- Aft beneath deck


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Emergency Towing SystemsTypical Arrangements Fwd


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Demo


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Mooring alongside a classic berth (quay)


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Mooring alongside a classic berth (quay) Different methods – see lab ship’s

technique Practical techniques – see lab ship’s

technique


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Mooring alongside a classic berth (quay)


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Mooring alongside a T-berth


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Mooring with 2 anchors


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Ship to ship


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SPM – Single Point Mooring Buoy


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SPM - buoy


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SPM - buoy


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FPSO – single point mooring


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FSO - operations


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STL – Submerged Turret Loading


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STP – Submerged Turret Production


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STP – Submerged Turret Production


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Safe fibre ropes1.1. Ropes should be covered when they are Ropes should be covered when they are

not being handled, and stowed away when not being handled, and stowed away when not in use at sea, to prevent not in use at sea, to prevent contamination by oils and chemicals, and contamination by oils and chemicals, and degradation by sunlight.degradation by sunlight.

2.2. Ropes must be kept away from heat, oil, Ropes must be kept away from heat, oil, paint and chemicals.paint and chemicals.

3.3. Ropes should be stowed on gratings for Ropes should be stowed on gratings for ventilation and drainage.ventilation and drainage.

4.4. Ropes must be examined regularly for Ropes must be examined regularly for wear, stranding, melting and powdering, wear, stranding, melting and powdering, and replaced if serious defects are found. and replaced if serious defects are found.


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Safe Wire Rope1.1. Wires should be lubricated regularly with Wires should be lubricated regularly with

an approved lubricant.an approved lubricant.2.2. Everyone who handles wires should wear Everyone who handles wires should wear

leather -palmed gloves to protect their leather -palmed gloves to protect their hands from snags.hands from snags.

3.3. Wires must be examined regularly for Wires must be examined regularly for wear, stranding, dry core, kinks, and wear, stranding, dry core, kinks, and excessively flattened areas. excessively flattened areas. They must be They must be replaced if the number of broken strands replaced if the number of broken strands (snags) exceed 10% of the strands in any (snags) exceed 10% of the strands in any length equal to eight diameters, or if any length equal to eight diameters, or if any other serious defects are found.other serious defects are found.


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Safe line handling – see lab1.1. Flake out all mooring lines on the deck, Flake out all mooring lines on the deck,

clclear, and ready to send. This will ensure ear, and ready to send. This will ensure that any fibre lines which have become that any fibre lines which have become buried on reels can be freed in advance, buried on reels can be freed in advance, when there is less likelihood of accidents. when there is less likelihood of accidents. Do not use a wire direct from a reel Do not use a wire direct from a reel designed only for stowing.designed only for stowing.

2.2. Have all necessary heaving lines, Have all necessary heaving lines, messengers, tails and stoppers available messengers, tails and stoppers available at the mooring station, and rat guards at the mooring station, and rat guards ready for use.ready for use.


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Flaking out mooring lines

Lover les aussières à la française

De trossen zijn klaar gelegd in franse bochten

To avoid that someone puts his foot/feet in a loop


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Safe position between mooring ropes

Position yourself away from the whip


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Putting the mooring rope on the warping head of the winch

The anchor winch has maximum power when it runs in the sense of picking up the anchor (anti-clock wise)


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Safe line handling – see lab3.3. Have sufficient crew available. Have sufficient crew available. 4.4. All crew should wear safety helmets and All crew should wear safety helmets and

safety shoes, and have no loose clothing safety shoes, and have no loose clothing which could become entangled in the which could become entangled in the winches or trapped by the lines. Gloves winches or trapped by the lines. Gloves should be tight fitting, to reduce the risk should be tight fitting, to reduce the risk of becoming trapped by lines, and should of becoming trapped by lines, and should have a leather palm to protect the hand have a leather palm to protect the hand against abrasion and prevent wounds against abrasion and prevent wounds caused by snags of wires; they should caused by snags of wires; they should provide adequate insulation in cold provide adequate insulation in cold weather.weather.


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Safe line handling – see lab5.5. When one seaman is handling a line on a When one seaman is handling a line on a

drum end, he should not stand too close drum end, he should not stand too close to the drum to avoid being drawn in. to the drum to avoid being drawn in. There should be an additional seamen There should be an additional seamen whose duty is to clear the loose line when whose duty is to clear the loose line when heaving, and supply the loose line when heaving, and supply the loose line when slacking.slacking.

6.6. The person operating the winch controls The person operating the winch controls should have a clear view of the entire should have a clear view of the entire area including any seaman handling lines area including any seaman handling lines with that winch.with that winch.


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Traditional stopper A traditional A traditional

stopper using a stopper using a single line may be single line may be used used onlyonly on a on a mooring line made mooring line made of natural of natural materials, as shown materials, as shown below, but such below, but such mooring lines are mooring lines are no longer common no longer common on board shipon board ship


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Safe line handling – see lab15.15. Stand well Stand well clclear of all lines under tension. ear of all lines under tension.

This means everybody, not just those This means everybody, not just those handling that line.handling that line.

16.16. Synthetic fibre ropes may break without Synthetic fibre ropes may break without warning, and the resultant whiplash may warning, and the resultant whiplash may cause severe injuries or even death.cause severe injuries or even death.

17.17. Synthetic fibre mooring ropes should be Synthetic fibre mooring ropes should be stoppered using two tails of fibre rope, half stoppered using two tails of fibre rope, half hitched under the mooring rope, with the hitched under the mooring rope, with the two free ends criss-crossed over and under, two free ends criss-crossed over and under, as shown in the diagram below: (This is as shown in the diagram below: (This is sometimes known as a Chinese stopper.)sometimes known as a Chinese stopper.)


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Safe line handling – see lab18.18. Mooring wires should be stoppered using Mooring wires should be stoppered using

a chain stopper with a well-spaced cow a chain stopper with a well-spaced cow hitchhitch (Lark’s head)( (Lark’s head)(Deux demi clefs Deux demi clefs renversées)renversées)(it is recommended that the (it is recommended that the two hitches are at least 25 cm. apart) and two hitches are at least 25 cm. apart) and with the remainder of the chain and its with the remainder of the chain and its rope tail turned up several times against rope tail turned up several times against the lay, as shown in the diagram below. the lay, as shown in the diagram below. The cow hitch is used because it is easily The cow hitch is used because it is easily pulled loose when no longer required, a pulled loose when no longer required, a clove hitchclove hitch (mastworp - (mastworp -Deux demi clefs à Deux demi clefs à capeler (noeud de cabestan))capeler (noeud de cabestan)) is likely to is likely to jam. jam.


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Chain stopper

Safe mooring1.1. All operations must be carried out ONLY under All operations must be carried out ONLY under

the direct orders of the supervising officer.the direct orders of the supervising officer.2.2. The supervising officer must ensure that The supervising officer must ensure that

communications with the bridge are -communications with the bridge are -CONTINUOUSLY maintained. If using radios all CONTINUOUSLY maintained. If using radios all calls should start with the ship’s name (to calls should start with the ship’s name (to avoid confusion), and then the caller should avoid confusion), and then the caller should immediately identify himself and who he is immediately identify himself and who he is calling to avoid confusion on one’s own ship A calling to avoid confusion on one’s own ship A spare fully-charged battery should be carried spare fully-charged battery should be carried whenever portable radios are used. A back up whenever portable radios are used. A back up system must be readily available at all times.system must be readily available at all times.


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Safe mooring3.3. Check with the bridge before sending the Check with the bridge before sending the

first lines, and before making any lines first lines, and before making any lines fast.fast.

4.4. Keep the bridge informed of distances off Keep the bridge informed of distances off the quay, any obstructions and other the quay, any obstructions and other moored ships, lighters or other floating moored ships, lighters or other floating objects.objects.

5.5. Advise the bridge if there is any Advise the bridge if there is any possibility that a slack line may become possibility that a slack line may become entangled in the propeller - or thrusters.entangled in the propeller - or thrusters.

6.6. Warn the bridge if any lines become Warn the bridge if any lines become excessively taut.excessively taut.


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Safe mooring7.7. Make fast and cast off tugs only on orders Make fast and cast off tugs only on orders

from the bridge.from the bridge.

8.8. When heaving lines are being thrown, When heaving lines are being thrown, ensure that all personnel ashore and on ensure that all personnel ashore and on board are alerted, and stand well board are alerted, and stand well clclear.ear.

9.9. The supervising officer must make sure The supervising officer must make sure he can always see both the winch he can always see both the winch operators and the particular line when operators and the particular line when giving orders for adjusting the tension in giving orders for adjusting the tension in a line.a line.


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Safe mooring10.10. Secure the lines as per the Master’s Secure the lines as per the Master’s

orders. i.e. which lines to leave on the orders. i.e. which lines to leave on the drums, which lines to make fast on bitts, drums, which lines to make fast on bitts, Which lines to leave in auto/self-tension, Which lines to leave in auto/self-tension, if any, and what level to set the controls.if any, and what level to set the controls.

11.11. Ensure rat guards are properly fitted to Ensure rat guards are properly fitted to all lines.all lines.

12.12. The supervising officer must remain at The supervising officer must remain at the mooring station, with his full crew, the mooring station, with his full crew, until he is dismisseduntil he is dismissed by the Master.by the Master.


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Plague Control ? Deratisation Rat guards


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Self Tensioning Winches Self tensioning winches can be set to a Self tensioning winches can be set to a

certain holding force. If this value is certain holding force. If this value is exceeded, then the winch automatically exceeded, then the winch automatically adjusts the length of wire to the new force adjusts the length of wire to the new force (too much holding force: slacking; too little (too much holding force: slacking; too little holding force: heaving). This system is holding force: heaving). This system is frequently used by ships that load and frequently used by ships that load and discharge quickly (container ships and Rodischarge quickly (container ships and Ro--Ro-vessels) or if there is a large tidal range Ro-vessels) or if there is a large tidal range in the port.in the port.


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Self Tensioning Winches

1.1. Control lever for the Control lever for the winchwinch

2.2. Cooling fanCooling fan

3.3. Control for the self-Control for the self-tension settingtension setting


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Self Tensioning Winches The heaving power of a winch is always lower than its The heaving power of a winch is always lower than its

render force.render force. This means that if a winch is left in self- This means that if a winch is left in self-tension, and the external forces increase, the line will pay tension, and the external forces increase, the line will pay out, and out, and it may not be possible to heave it in again until it may not be possible to heave it in again until such external forces reducesuch external forces reduce. Also, the render force of the . Also, the render force of the winch is much less than the holding power of the brakewinch is much less than the holding power of the brake

Self-tensioning winches at opposite ends of the ship can Self-tensioning winches at opposite ends of the ship can work against each other, so that the ship can sometimes work against each other, so that the ship can sometimes ‘walk’ along the berth, when an external force is applied ‘walk’ along the berth, when an external force is applied at one end.at one end.


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Self Tensioning Winches Hence it is recommended that mooring lines are Hence it is recommended that mooring lines are NOTNOT left left

in self-tension once the ship is secure alongside. With in self-tension once the ship is secure alongside. With short breast lines in fair weather, these controls may be short breast lines in fair weather, these controls may be useful during rapid load/discharge operations. However, useful during rapid load/discharge operations. However, those winches which are directly counteracting any those winches which are directly counteracting any external forces external forces mustmust be left on the brake. be left on the brake.

Self-tensioning winches are useful during berthing Self-tensioning winches are useful during berthing operations with reduced manning, as once the line is operations with reduced manning, as once the line is ashore and the controls set, they will reel in any slack, ashore and the controls set, they will reel in any slack, maintain the tension in the line, and prevent the line being maintain the tension in the line, and prevent the line being damaged throughdamaged through excessive strain.excessive strain.


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Keeping moorings taut The OOW must ensure that the mooring lines are kept The OOW must ensure that the mooring lines are kept

sufficiently taut at all times to keep the ship firmly sufficiently taut at all times to keep the ship firmly alongside. At rapid loading or discharging berths, the alongside. At rapid loading or discharging berths, the Chief Officer may assign additional crew to assist the Chief Officer may assign additional crew to assist the OOW, as the operation of adjusting the lines may have to OOW, as the operation of adjusting the lines may have to be done frequently. The 00W must never attempt to be done frequently. The 00W must never attempt to adjust a mooring line by himself, unless it is permanently adjust a mooring line by himself, unless it is permanently wound on its own drum.wound on its own drum.

If the lines are not in equal tension, they may part in If the lines are not in equal tension, they may part in succession if the ship is subject to exceptional high forces, succession if the ship is subject to exceptional high forces, such as very strong winds, large swells or water surges such as very strong winds, large swells or water surges from other ships passing too close and/or too fast. from other ships passing too close and/or too fast.


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Keeping moorings taut Brake linings can lose their grip when oil and rust are present, Brake linings can lose their grip when oil and rust are present,

and are susceptible to loss of holding power during periods of and are susceptible to loss of holding power during periods of rain or high humidity. rain or high humidity.

The OOW should remember to adjust any fire wires as the The OOW should remember to adjust any fire wires as the ship’s freeboard changes, to ensure that their ends remain ship’s freeboard changes, to ensure that their ends remain clear of the water.clear of the water.

It is essential for the OOW to check the moorings when other It is essential for the OOW to check the moorings when other ships are arriving at or leaving from the berth immediately ships are arriving at or leaving from the berth immediately ahead or astern of their ship. ahead or astern of their ship.

It is good practice for the OOW to be in attendance forward It is good practice for the OOW to be in attendance forward or aft whenever the adjacent ship is arriving or sailing to or aft whenever the adjacent ship is arriving or sailing to watch out for contact damage, or other incidents, in addition watch out for contact damage, or other incidents, in addition to monitoring the moorings.to monitoring the moorings.

Fire wire Strong steel wire 1 end is put on a

bollard Other end is hanging

overboard +/- 1 meter above the water

The outer end is held in position by means of a weak line.

Middle part is flaked out on deck

In case of fire a tugboat can grab the outer eye and pull the tanker free of the berth


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Excerpt from terminal rules and Excerpt from terminal rules and regulations - Saoudi Arabiaregulations - Saoudi Arabia

TOWING-OFF WIRES OF ADEQUATE STRENGTH AND CONDITION MUST BE MADE FAST TO BOLLARDS ON THE TANKER. FORWARD AND AFT, AND THEIR EYES RUN OUT AND MAINTAINED AT OR ABOUT THE WATERLINE. THE WIRES MUST BE OVER THE OFFSHORE SIDE.

IN ORDER THAT SUFFICIENT WIRE CAN BE PUT OUT TO ENABLE THE TUGS TO TOW EFFECTIVELY, ENOUGH SLACK MUST BE RETAINED BETWEEN THE BOLLARD AND CHECK AND PREVENTED FROM RUNNING OUT BY A ROPEYARN OR OTHER EASILY BROKEN MEANS


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Chafing (Frotter – Raboter) The OOW must check the moorings at least hourly during The OOW must check the moorings at least hourly during

his watch, not only to ensure they remain taut but also to his watch, not only to ensure they remain taut but also to look out for chafing, where the rope rubs against an look out for chafing, where the rope rubs against an obstruction, and may part. This may occur when the ship obstruction, and may part. This may occur when the ship is surging back and forth along the quay due to a large is surging back and forth along the quay due to a large swell, or when there is excessive movement of a mooring swell, or when there is excessive movement of a mooring buoy. Synthetic fibre ropes possess very low resistance to buoy. Synthetic fibre ropes possess very low resistance to chafing when under load; the friction generates heat chafing when under load; the friction generates heat which causes them to melt and fuse, and the rope is then which causes them to melt and fuse, and the rope is then permanently weakened, and may part quite quickly.permanently weakened, and may part quite quickly.


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Chafing (Frotter – Raboter) Ropes may chafe by rubbing against each other, or Ropes may chafe by rubbing against each other, or

against the ropes of another ship. The officers on stand-by against the ropes of another ship. The officers on stand-by fore and aft during mooring operations must be alert for fore and aft during mooring operations must be alert for this when sending ropes to different bollards ashore this when sending ropes to different bollards ashore through different leads on board. through different leads on board. IIf they notice any f they notice any chafing, they should have that line removed and sent from chafing, they should have that line removed and sent from a different lead. Short leads with substantial dips are a different lead. Short leads with substantial dips are prone to chafing on the ship’s structure.prone to chafing on the ship’s structure.


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Chafing Sometimes a change in freeboard, or some external Sometimes a change in freeboard, or some external

factors such as a change in the sea state, may cause lines factors such as a change in the sea state, may cause lines to start chafing. If he notices any chafing, OOW must to start chafing. If he notices any chafing, OOW must clear the obstruction, change the lead of the mooring clear the obstruction, change the lead of the mooring rope, or wrap the rope in canvas or some other material rope, or wrap the rope in canvas or some other material to bear the rubbing and wearing away action. The outside to bear the rubbing and wearing away action. The outside of the canvas may be greased to reduce the friction, but of the canvas may be greased to reduce the friction, but this grease must not be allowed to remain in contact with this grease must not be allowed to remain in contact with fibre ropes as it will cause them to deteriorate. The OOW fibre ropes as it will cause them to deteriorate. The OOW must always advise the Chief Officer of his observations must always advise the Chief Officer of his observations and actions.and actions.


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Emergencies Occasionally unexpected changes of load may cause the Occasionally unexpected changes of load may cause the

brakes of the mooring line drums to slip, and the vessel brakes of the mooring line drums to slip, and the vessel is at risk of moving off the berth. DO is at risk of moving off the berth. DO NOTNOT RELEASE RELEASE THE BRAKES AND ATTEMPT TO HEAVE THE THE BRAKES AND ATTEMPT TO HEAVE THE SHIP BACK ALONGSIDE USING ONLY THE SHIP BACK ALONGSIDE USING ONLY THE POWER OF THE WINCH.POWER OF THE WINCH.

The recommended action is:The recommended action is:1.1. If the winches are in self-tension apply the brakes IN If the winches are in self-tension apply the brakes IN

ADDITION.ADDITION.2.2. If the brakes are in use, tighten them, put the winch in If the brakes are in use, tighten them, put the winch in

gear and heave on as many lines as possible.gear and heave on as many lines as possible.


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Emergencies3.3. Inform the senior officers, and seek extra crew Inform the senior officers, and seek extra crew

assistanceassistance4.4. Summon tug assistance if necessary.Summon tug assistance if necessary.5.5. Consider reducing the freeboard by ballasting.Consider reducing the freeboard by ballasting.6.6. The OOW should remember that brake holding power The OOW should remember that brake holding power

is always greater than winch heaving power, but that is always greater than winch heaving power, but that the two together increase the load.the two together increase the load.

For example:For example:Winch render force Winch render force = 35 tonnes.= 35 tonnes.Brake holding power Brake holding power = 65 tonnes.= 65 tonnes.Total holding power Total holding power = 100 tonnes.= 100 tonnes.


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Emergencies

He should be careful this does not exceed the breaking He should be careful this does not exceed the breaking strain of the rope, or the safe working load of the leads strain of the rope, or the safe working load of the leads and rollers. However, in an emergency it will usually be and rollers. However, in an emergency it will usually be preferable to endeavour to hold the ship in position and preferable to endeavour to hold the ship in position and risk breaking the lines.risk breaking the lines.


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Mooring equipment ashore


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Equipment ashore Bollards and bitts Winches - capstans Quick release hooks Laser docking systems Mooring line monitoring systems Fenders


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Bitts and bollards


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Capstans


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Quick Release Hooks The basic starting point to any

integrated mooring system Can be released manually or

(electric, hydraulic or telemetry) and can incorporate load pins for optional multipoint computer-based remotely mooring line tension monitoring systems


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Quick Release Hooks


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Quick release hooks

Explosion proof double hook unit

Quad. hook with load monitoring and remoter release system


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Mooring Line Monitoring System

The vessel Mooring The vessel Mooring Line Monitoring system Line Monitoring system (MLM), provides real (MLM), provides real time monitoring of all time monitoring of all mooring lines and mooring lines and warns of excessive or warns of excessive or out-of-range loads. out-of-range loads.

Changing weather Changing weather conditions or current conditions or current loading can cause loading can cause unequal load sharing unequal load sharing within the mooring within the mooring system. This can lead system. This can lead to potential failure of to potential failure of mooring lines and mooring lines and damage to jettydamage to jetty


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Mooring Line Monitoring System

Load on the hooks is measured by load pins

Data is transferred to the jetty control room

Data is completed with environmental data and data concerning the movement of the ship alongside


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Environmental data Data is collected

by a buoy and presented on graphic display


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Laser docking systems The primary benefit of a Docking Aid System or

DAS is the provision of real time data of the vessel’s position and progress relative to the jetty by measuring distance from the jetty and speed of approach in the critical 0 to 200 meters zone.

With this data the vessel’s master and pilot can better direct tug and shipboard personnel in the safe manoeuvring of the vessel towards the jetty and minimize any potential for damage to the berth


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Laser docking systems Typically, two sensors are located

on the jetty measuring distance to bow and stern sections of the ship.

This together with average speed are captured at the jetty control unit and displayed to the ship and mooring crew on wireless monitor, computer screen or jetty mounted display board, as required.

Earlier systems used radar sensors, however today laser sensors are the most reliable technology employed for vessel docking.


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Laser docking systems


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Docking systems – GPS based f.i. e-fix system

Ship trials (speed and manoeuvring)

Oil and gas tanker approaches and docking operations

SPM/FSO Docking and Drift Warning

Oil rig positioning Navigation of ships

into locks & docks Ferry operations


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Docking systems – GPS based f.i. e-fix system It should be noted that the E-Sea Fix system can be It should be noted that the E-Sea Fix system can be

integrated into existing Laser Docking Systems. integrated into existing Laser Docking Systems. All data from an existing Laser Docking System All data from an existing Laser Docking System

(such as environmental data, load arm monitoring, (such as environmental data, load arm monitoring, mooring load monitoring and drift warning mooring load monitoring and drift warning information) can be relayed and displayed on the information) can be relayed and displayed on the pilot monitor.pilot monitor.

A receiver is capable of receiving signals from both A receiver is capable of receiving signals from both the US constellation as well as the Soviet based the US constellation as well as the Soviet based GLONASS constellation. This dual constellation GLONASS constellation. This dual constellation ensures that the number of satellites visible to the ensures that the number of satellites visible to the receivers is maximised. receivers is maximised.


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Accuracy Speed accuracy better than any ship’s

log, ± 1 cm per second i.e. ± 0.02 knots Heading accuracy better than any gyro

system, approximately ± 0.01 degree Rate of turn better than any rate gyro

system, approximately ± 0.02 degree/second and up

Position accuracy to a few centimetres


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Docking systems – GPS based f.i. e-fix system

Signal is used as input for an ECDIS based on C-map or S-57 maps.

Portable version exists


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Berth management systems A « Berth Manager» monitors the vessel

approach, mooring load and environmental situation in a single integrated system, with a range of optional displays, readouts and functions, and provides the port operator with comprehensive reporting on the behaviour of vessels while in the confines of the port. The system assists the docking procedure and monitors mooring performance.


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Berth management systems


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Fenders Used to:

Divide the load Protect the berth Protect the ship

Fenders can be fixed or mobile


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Yokohama Fenders


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Yokohama Fenders


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Fixed fenders


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Mooring equipment on board


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Mooring equipment on board Heaving line (ligne d’attrape) Messenger (grelin) Tails


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Heaving line (ligne d’attrape)


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heaving line (Ligne d’attrape)


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Messenger - grelin


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Tail (allongement de la touline)


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Passing ropes ashore Before arriving at the dock all crewmembers should Before arriving at the dock all crewmembers should

put on their Personal Protective Equipment and put on their Personal Protective Equipment and move out onto the deck. All lines should be move out onto the deck. All lines should be prepared for docking making sure that they will feed prepared for docking making sure that they will feed out freely.out freely.

There should always be someone on the dock to There should always be someone on the dock to receive the line. receive the line.

Do not attempt to throw the line to the bitt.Do not attempt to throw the line to the bitt. If the boat is to be moored some distance from the If the boat is to be moored some distance from the

dock a messenger linedock a messenger line (grelin) (grelin) with a monkey’s fist with a monkey’s fist can be thrown and then hauled in to transfer the can be thrown and then hauled in to transfer the mooring line safely to the dock.mooring line safely to the dock.


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Passing ropes ashore If you are sharing the bitt or bollard with another If you are sharing the bitt or bollard with another

vessel feed the eye of the mooring line through the vessel feed the eye of the mooring line through the eye of the line already on the bitt and then place the eye of the line already on the bitt and then place the eye over the bitt.eye over the bitt.

This will allow you or the other vessel to quickly This will allow you or the other vessel to quickly remove a line without disturbing the remaining line.remove a line without disturbing the remaining line.


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Passing ropes ashore


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Putting 2 ropes on the same bitt

1.Wrong2.Correct

The « other » ship can leave without disturbing our mooring configuration


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Passing ropes ashore While handling lines you must be very conscious of While handling lines you must be very conscious of

the placement of your hands and feet in proximity the placement of your hands and feet in proximity to the line. Never put your hand in the bight of the to the line. Never put your hand in the bight of the line at the bitt, and watch that you do not step into line at the bitt, and watch that you do not step into the bight of the line on the deck with your foot. If the bight of the line on the deck with your foot. If the boat surges you can be caught in an instant, the boat surges you can be caught in an instant, resulting in serious injury or death.resulting in serious injury or death.


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Passing ropes ashore Never place yourself in Never place yourself in

a position where the a position where the line can pinch you up line can pinch you up against the bulwarks or against the bulwarks or equipment on deck. equipment on deck. You will never be able You will never be able to move quick enough to move quick enough to get out of the way or to get out of the way or have the strength to have the strength to keep the line off you!keep the line off you!

Mooring of ships - forces

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