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SSEP JUNE 2017

Answer any five questions

All Questions carry equal marks.

Q1. In engine rooms that are operated under UMS conditions describe with the aid of sketches how the following are monitored: A. The perforation of a high pressure fuel pipe; B. The imminence or possibility of a scavenge fire; C. Condition that may be conducive to a crankcase explosion

Answer:- (A) High pressure fuel pipes can be fractured by excessive vibration causing the fuel oil at high pressure to spray on the hot exhaust pipe causing a dire. To prevent this dangerous situation especially when the engine room is unattended is to have these HP pipes protected by a casing pipe.

Due to a leaking pipe the csing pipe gets filled up must be evacuated or else the casing pipe gets pressurised. So each casing pipe is connected by a drain pipe to a leak-off tank fitted with a level ialarm probe to indicate when a pipe is fractured or holed, so that suitable corrective action can be immediately taken. Refer to the sketch given under.

(B) The indication of a scavenge fire which is impending is given even before theoily vapour ignites by the temperature bi metal strip contacting the the contact point and closing the circuit instigating the alarm and light signal , so that suitable corrective action can be taken before the fire becomes big.Refer to the sketch given below

(C) CC oil mist detector.:-

Crosshead type slow speed diesel engines use the comparator type of mist detector ,which is described as herewith. The comparator type uses an average oil mist density as the datum. Qil mist is continuously drawn by a motor driven fan through pipes connecting the detector to the engine.Small bore flexible pipes connect the detector to each crank. Chamber,A rotary sampling valve joins each sampling pipe in turn to the measuring tube.Another sample of oil mist from the remaining tubes (average value) is passed to the reference tube..The measuring tube thus receives a sample of oil mist from each crank chamber. In turn and compares the density of that with the reference tube which receives the average oil mist sample from all the remaining crank cases,In addition ,once during each

scanning cycle the rotary valve passes the average sample to the reference tube and compares with a sample of clean air drawn through the measuring tube., At position ‘O’ ‘’clean air is admitted to both reference and measuring tubes for ‘O’ caliberation.. Light from an exciter lamp is reflected by mirrors along the axes of both reference and measuring tubes energising the photo electric cells at the end of each tube.. Under normal working condition the oil mist density is he same in both tubes and hence the outputs from photo cell are balanced and the indicator reading is ‘ O’ or very near to it.

If an increase in oil mist density of an individual chamber is detected the meter needle will advance and the alarm , visual and audible will operate. The obscuration of light beams in the tubes is then unequal, a current flows in the external circuit to operate the alarm. Simultaneously the rotary valve will automatically be stopped by a magnetic control. This indicates the crankchamber where the hot spot has occurred.

Q2 fire in the exhaust gas boiler on a motor ship may develop in two or three stages. With reference to such situations; discuss: A. The factors which could be responsible for initiation and development of: i) Ignition of soot; ii) Small soot fires; iii) High temperature fires; B. State the standing instruction you, as Second Engineer Officer, would issue to watch keepers with respect to the action to be taken in the event of a boiler uptake fire

Answer:- The spaces between the fins in the finned tubes of the exhaust boiler are thickly covered by oily soot having accumulated there for a considerable period. This oily soot when heated up by the exhaust gas during full service speed of the engine causes the oil to vapourise and form a halo around With the engine operating at service speed the excess air supply and its high temperature (3500C) are both favourable to start ignition of the soot. All it needs is a flying cinder to ignite the oil vapour –air mixture.

This is the genesis of the soot fire.

(2) The soot adhering to the fins catch fire and this is the initiation of a soot fire. (3) As the fire develops onwards by burning the accumulated soot the temperatures reached are high and capable of burning and melting the thin walled fin tubes allowing water in circulation through the tubes to leak out. The leaking water quickly converts to steam because of the excessive heat of the fire, the steam gets superheated to a very high temperature when it disassociates into hydrogen and oxygen. The liberatedhydrogen feeds the soot fire which now intensifies into a high temperature fire also named hydrogen fire.

(b) STANDING INSTRUCTIONS: (1) An uptake fire is recognized by the sounding of the uptake

temperature alarm. (2) When this alarm is sounded and recognised. Go to the Fiddley deck or upper platform where the forced circulation exhaust gas economiser is located, feel the casing plates or observe if the paint is blackening indicating existence of a fire. (3) Confirm from Bridge if any flame or sparks leaving the economiser

uptake. (4) Slow down main engine, inform C/E and 2/E, and stop M/E. (5) stop circulation pump to economizer (6) Start boundary cooling of economiser casing plates. (7) When sufficiently cool, open inspection door on casing plate to for inspection.

Q3. With reference to a periodically unattended machinery space of a dry cargo vessel discuss the requirements For A. Protection against flooding; B. Control of propulsion machinery from the navigating bridge.

Answer:- The concept of automation and particularly the requirements of an unattended machinery space has six essential items for constant monitoring and of which the requirement of protection against flooding and protection against fire are considered most essential.

These are:

A rapid response automatic fire detection and alarm system. Centralised fire fighting stations. Bilge alarms or monitoring flooding conditions. Bridge control. Alarm systems for all essential machinery in the machinery

space which includes steering systems also

The reason for selecting these two items may be explained as:

The ship is in the midst of the sea always and hence very vulnerable to flooding by water. Hence monitoring and protection against flooding becomes very important and hence provided for. The monitoring of flooding is provided for all likely spaces in the ship. Particularly the machinery spaces and the hold spaces. The requirement of monitoring the flooding of hold spaces was an ammendment by the SOLAS protocol of 1988 and is introduced in ch 12 of the present SOLAS.

The ships main engines as well as its auxiliary engines use fuel oil , the combustion of which generates the power, The ship has to store this fuel , transfer it as necessary , purify it for optimization of its combustion. These operations make the machinery space vulnerable to any accidental fire . Hence the need for monitoring conditions for propagating the fire and also a protection device to extinguish the fire

The objective of automation which includes the concept of UMS is reduction of man power so that operation costs are reduced . The man power is mainly utilised for

preventive and correctional maintenance with the watch keeping function taken over by instrumentation including automation

On the ship the bridge can never be unmanned since the shipping industry has not yet formulated a safe unmanned navigation system for the ship, although this is possible and may become a routine feature in future As of now all ships navigation bridges have to be manned at all times when the ship is sailing

With manned machinery systems the operation of the engine was being carried out by the engineers in the engine room on the basis of orders issued from the bridge through the telegraph

With the advent of automation and UMS, the engine operation function is provided to the bridge control so that the machinery space can be truly designated as UMS and this provision is very simply provided by having a suitable bridge operating console with the parallel controls for the following:

Air start system. Changing the direction of rotation of the engine. Changing to fuel and setting the speed or load of the

engine

Q4. Sketch a line diagram of an automatic water sprinkler, fire detecting alarm and extinguishing system type fitted in accommodation and service spaces of a passenger vessel. for accommodation spaces; B. Describe the operation of this system; C. State the action that should be taken after the use of the above fire fighting system.

Anseer:- (A)

(B) The structural fire protection is based on zones separated by fire proof bulkheads and having fire proof divisions within them. A network of sprinkler heads is arranged throughout the spaces to be protected. Each sprinkler head is normally kept closed by a quartzoid bulb which is almost filled with a liquid having a high expansion ratio. When the liquid is exposed to abnormal heat it expands rapidly to completely fill the bulb. Further expansion is sufficient to shatter the bulb. Water, maintained under pressure by compressed air, is then expelled from the sprinkler head or heads in the form of a heavy spray. Each head adequately showers a deck area of 16m2 and the heads are arranged so that every part of each space requiring protection, can be covered by water spray. The system shown has a pressure tank which is kept part-filled with fresh water and pressurized to 8 bar compressed air. When the pressure drops below 5.5 bar, a salt water pump cuts in automatically so that if the sprinklers operate a supply of water is maintained.Each installation is divided into sections containing up to 200 sprinkler

heads and each section has an alarm valve When a sprinkler comes into operation water flows through the section alarm valve. The water lifts the non-return valve exposing an annular groove which connects to a diaphragm alarm switch. This switch is coupled to an alarm and to an indicator panel on the bridge which gives audible and visual warning that a sprinkler has operated and fire has probably broken out in the section indicated. Fires have frequently been found to have been extinguished by the system alone. When any occurrence has been dealt with the stop valve, which is usually locked open, may be closed to replace the sprinkler head which has operated and to enable the section to be drained of salt water before being filled with fresh from the system. The sources of water are, fresh water stored in the sprinkler tank for the initial supply followed by sea water pumped by the sprinkler pump

When the liquid is exposed to abnormal heat it expands rapidly to completely fill the bulb. Further expansion is sufficient to shatter the bulb. Water, maintained under pressure by compressed air, is then expelled from the sprinkler head or heads in the form of a heavy spray. Each head adequately showers a deck area of 16m2 and the heads are arranged so that every part of each space requiring protection, can be covered by water spray

In accommodation and service spaces , the sprinklers will come into operation within the temperature range from 680 C to 790 C . In locations such as drying rooms and galleys where high ambient temperatures might be expected the operating temperature may be increased by 300C above the maximum deck head temperature.(C) The action to be taken after use of the system sre as follows: * The sprinkler tank must be replenished with fresh water. * The damaged sprinkler heads must be replaced. * All the valves in the system which were operated should be brought back to the original operating condition.

Q5. With reference to arresting the headway of vessels of considerable mass, give reasoned opinions on EACH of the following statements: A. Full power availability for astern running of the propeller is inconsequential; B. Results have been disappointing in those instances where rudders have been adapted to act as retarders; C. Discreet use of transverse thrust units may reduce stopping distance.

Answer:- (A) Full power availability for astern running.

The reasons on non availability of full power for astern running are:

The existence of the stern body of the ship prevents free flow of the wake when going astern.

The ships propeller is designed to provide the necessary pitch utilising the driving face of the propeller which is the ahead driving face. The astern driving face is not designed for optimization. Only in the case of the controllable pitch propeller both faces are equally designed.

With both these drawbacks the power available for astern propulsion is therefore reduced and about 85 percent is only available. (B) The use of rudders: The rudder has an area which is about 1/60 of the product of the length of the ship and the depth of the ship or the profile area of the immersed body This area is a small fraction of the immersed profile and if utilised as a turning force it can only create a small deviation in direction which in most cases is not adequate to prevent a collision. The rudder is also not effective beyond 350 on both sides.

(C) Use of transverse thrusters : Ships provided with transverse Bow thrusters can use this device as it is capable of giving maximum torque and it is not dependent on the ahead or astern speed of the ship, unlike the regular rudder which is dependent on the speed of the ship for its steering action. To summarize the above statements and to find a safe solution to avoid collisions , it is essential to carry out a crash stop test on all single screw ships and record the results in the distance travelled by the ship before coming to dead stop and have these results displayed on the Bridge for the guidance of pilots and navigators, so that preventive action can be taken in the correct time and distance.

Q6. Briefly describe the environmental impact of NOx and SOx and allowable limitations are per Annex VI of MARPOL in emission control areas and outside emission control areas. B. Briefly describe methods to control NOx emission.Answer:- (A) NOX are the oxides of nitrogen and SOX is mainly sulphur di oxide. Both these gases are toxic in nature and hencepollute the atmosphere and the air we breathe causing respiratory disorders and hence needs to be controlled . The heavy fuel we burn in the ship’s engines contains small quantity of sulphue and as per the tier 2 era (till 2020) it is restricted to 3.5 percent max (m/m). After 2020 the restriction is reduced to 1.5 percent. During the process of combustion in the engine the sulphur in the fuel burns to sulphur –di-oxide utilising the oxygen from the air for combustion. Nitrogen oxides are not normal products of combustion. When the fuel is burnt in the boiler nitrogen oxides are not formed because the maximum temperature of combustion in the boiler is 17000 C. For the formation of NOX the temperature combustion should be over 20000 C and this occurs in the combustion process within the main engine and aux engines because of the optimization of the quality of combustion ny supercharging the air, proper atomisation of the fuel, proper penetration and turbulence given to the air fuel mixture.All these added qualities result in a high combustion temperature crossing 20000C. As per Tier 2 standards the limitations of SOX and NOX are as follows:

Out side emission control areas SOX is limited by using fuel containing sulphur not more than 3.5 percent. NOX is limited as follows :(a)For slow speed main engines it is 3.4 g/KWh with engine RPM not more than 130 (b)For medium speed aux engines it is 9*n0.2 when n is the RPM of the engine and is less than 2000 RPM.(c)For high sped aux engines over 2000 RPM the NOX limitation is 2.0g/KWh.* Emission control areas: The limitation of sulphur content in the fuel oil 0.1 percent m/m NOX limitations are same as given for outside areas. These values are valid up to 1st JAN 2020

(B) Primary methods:- When engines have been delivered to ship builders , they have been prepared to meet the Annexe 6 NOX limitations in accordance with the speed requirements .This is achieved by adjusting a small delay in injection timing resulting in a reduction of peak pressure corresponding to lower peak temperature of combustion. It should be understood that NOX occurs when combustion temperatures go over 22000 c . This compliance with the regulation results in an increase of S.F.O.C from 3% to 5%

Secondary method:- Water emulsification resulting in NOX reduction 20%--50%. The NOX reducing mechanism is created by the introduction of water into the combustion space which whilst improving the atomisation results in better combustion ,and at the same time reducing the combustion temperature to a value below 2200 0 c.

E.G.R .system:- Exhaust gas re circulation system. The NOX reduction is achieved by reducing the local maximum combustion temperature in the combustion chamber and reducing the concentration of oxygen by circulating part exhaust gas with air or introducing water vapour with air into the combustion chamber.

Scavenge air moisturising:- In this system ,after the turbocharger compressor, with the assistance of the E.G.R. blower ,high pressure water spray humidification is the most suitable solution for large two- stroke slow speed engines.

Q7. Why is ballast water treatment important and needed? What regulations are guiding BWT? B. What is current status of the IMO BWM convention ratification and what is included in the certification and type approval process?

Answer:- (A) Ballast in the form of sea water carried by the ship is a necessity for the stability and trim correction requirements of the ship under different loading conditions. Hence the need for ballast water is very essential for the safe operation of the ship.

About sixty years back the ships were not big enough to cause changes in the densities and composition of sea water in different regions in the world since the quantities carried and transferred were not large . But of late with the sizes of ships crossing 300,ooo DWT , the damage to the marine ecology systems has caused concern and this has resulted in the need for a ballast water convention which will regulate the transfer as well as the treatment of ballast water.

The International Convention for the Control and Management of Ships' Ballast Water and Sediments (Ballast Water Management Convention) 2004, is an international maritime treaty which requires Signatory flag

states to ensure that ships flagged by them comply with standards and procedures for the management and control of ships’ ballast water and sediments The Convention aims to prevent the spread of harmful aquatic organisms from one region to another and halt damage to the marine environment from ballast water discharge, by minimising the uptake and subsequent discharge of sediments and organisms From 2024 all ships are required to have approved Ballast Water Management Treatment System, according to the D2 standard (see below). Existing ships are required to install an approved system, which may cost up to 5 million USD per ship to install.[2] To assist with implementation the IMO has released 14 Guidance documents in regards to the Convention including the G2 Guidelines for Ballast Water Sampling, G4 Guidelines for Ballast Water management and G6 Guidelines for Ballast Water Exchange.

GUIDELINES FOR APPROVAL OF BALLAST WATER MANAGEMENT SYSTEMS (G8) 1

INTRODUCTION The 2016 Guidelines for approval of ballast water management systems (G8) are aimed primarily at Administrations, or their designated bodies, in order to assess whether ballast water management systems meet the standard as set out in regulation D-2 of the "International Convention for the Control and Management of Ships' Ballast Water and Sediments," hereafter referred to as "the Convention". In addition, these guidelines can be used as guidance for manufacturers and shipowners on the evaluation procedure that equipment will undergo and the requirements placed on ballast water management systems. These Guidelines should be applied in an objective, consistent and transparent way and their application should be evaluated periodically by the Organization.

Goal and purpose The goal of these Guidelines is to ensure uniform and proper application of the standards contained in the Convention. As such the Guidelines are to be updated as the state of knowledge and technology may require. The purpose of these Guidelines is to provide a uniform interpretation and application of the requirements of regulation D-3 and to: .1 define test and performance requirements for the approval of ballast water management systems; .2 assist Administrations in determining appropriate design, construction and operational parameters necessary for the approval of ballast water management systems; .4 provide guidance to Administrations, equipment manufacturers and shipowners in determining the suitability of equipment to meet the requirements of the Convention and of the environmental acceptability of treated water; and .5 assure that ballast water management systems approved by Administrations are capable of achieving the standard of regulation D-2 in land-based and shipboard evaluations and do not cause unacceptable harm to the ship, crew, the environment or public health.

(B) The current status of the convention ratification is that this convention and its regulations have come into force from 8th SEPTEMBER 2017.

In the certificate the the management process as per guidelines D-3 is specified.

The results of tests carried out are included in the type approval certificate.

Q8. Receiving of bunkers is an important aspect of a Senior Engineers responsibility A. Stale the safety precautions that should be observed when bunkering; B. Explain the importance of taking samples when bunkering; C. Explain a preferred method of collecting samples. D. State the effect of each in a fuel oil – i. High density; ii. Lowpour point; iii. High water content, iv. High amount of cat fines

Answer:- The function of receiving bunkers is a regular feature of shipboard operations and a necessary operation. It should always be considered as a critical operation because of the imminent danger of an oil spill or overflow. Even when we are very careful an oil spill can occur caused by vapour /gas lock pressure in ships which are badly trimmed

Emergency preparedness ;- For example consider tanker discharging cargo at an oil terminal and she is trimmed heavily by stern a position arranged by the C/O for ensuring efficient stripping of the cargo tanks. In this situation the bunkering operation is also proceeding. Assuming the ship has a deep tank for D/O which is being bunkered .In this situation there is a possibility of a powerful vapour lock being created in the tank ,especially if the air pipe is aft of the tank. The situation can be understood from the following sketch

.

Hence in such situations bunkering should not be done ,but stopped till the trim is corrected. How ever the emergency or contingency action would be to use approved oil spill dispersant on the spill and this should be kept handy at the bunkering station. Follow up action suggested are:

(1) Identify the source of spill/leak and initiate measures to stop or minimise the out flow.

(2) Transfer the spilled oil by handy containers into overflow tank through air-pipe after dismantling flame trap.

(3) The possibility of leakage from defective valves should not be discounted. Pressure on these valves should be relieved ,if possible by draining the lines into an empty tank available.

To overcome this criticality and ensuring that the bunkering operation is carried out safely, the check list itself should be a contingency plan. This check list is so designed that it takes care of all such situations This check list should be filled up before commencing bunkering operations, and also checked during the bunkering operation.

BUNKERING CHECK LIST

SL No

ACTIVITY VERIFICATION

1 BUNKER PLAN NO1&2(P) and NO1,2 (S) made empty to receive bunkers.

2 HOSE CONNECTION Connected to manifold and flanges tightened with new joint.

3 DECK SCUPPERS All properly plugged and cemented on main deck and other Decks

4SEQUENCE OF BUNKERING

no1(p) and no 1(s), on completion no 2(p) and no2(s) Total bunkers tobe taken is 90% of total tank capacity

5 DRAFT FORWARD 9.5 METRES

6 DRAFT AFT 9.6 METRES trim negligible. No list

7 PIPE ALIGN MENT

Deck master valve open .Tank 1(p) and 1(s)open at the tanks. Manifold valves i(p) and 1(s) open and to be controlled by duty Engineer in E/R

8 OVERFLOW TANK Empty and ready to take any over flow

9 OVERFLOW LINES Checked. alarms and indicators, working.

10SOUNDING EQUIPMENT

pneumercator gauge tested and found in order

11SOUNDING INSTRUCTIONS

soundings to be taken every 15 minutes whilst bunkering and list to be corrected by suitably controlling flow in tanks.

12 COMMUNICATION

Bunkering station to E/R Control room tested and working Bunkering station to Barge by walkY talkie tested and channel Selected.

13 OIL SPILL DISPERSANT made available at the bunkering station

14 FIRE PROTECTION one portable foam extinguisher made available at bunkering Station. One

fire hose with spray& jet nozzle readily Connected to hydrant made available.

(B) Bunker samples are needed to be taken for future testing in the event that the bunkers supplied are not as per the specifications which has become evident by faulty working of the engine due to the sub standard quality of the fuel bunkered. For this reason old existing bunkers must not be mixed with new bunkers so that the faulty bunker parcel can be identified.

(C) During bunkering operations ,if the bunkers are supplied from a barge find out from which all tanks in the barge the bunkers are supplied from. accordingly two samples must be taken for each tank of the barge from where bunkers were supplied. The samples are taken out of a drain cock at the bunkering manifold situated within a drip tray .as shown in sketch.

Before taking out a sample take out at least 3 to 4 buckets of oil initially to clear out any superficial sludge. This will give a proper representative sample .The barge master takes one sample and the ship will retain the other sample. For future reference if needed in a

quality dispute.. The sampling drain has an internal pipe extending to the centre of the manifold. This arrangement enables the oil sample truly representative.

If bunkers are supplied from shore tanks 2 samples must be taken from each tank from which bunkers have been supplied.

(D) High density of oil:- This requires special purification technique , especially when the density is greater than the density of water. Ships should be fitted with special purifiers specially adapted for this type of bunkers.

Low pour point:- When the fuel oil has a low pour point it becomes difficult for the transfer of daily fuel requirement for the engine. Especially in cold weather. To cope up with this difficulty the bunker tanks should be fitted with steam heating lines.

High water content:- the purification throughput is to be reduced so that purification quality is improved.

High amount of cat fines:- To remove the tiny particles of cat fines the oil has to be passed through a clarifier which operates in series with the purifier.