MARCH 2018

MARINE ENGINEERING KNOWLEDGE (GENERAL) TIME ALLOWED - 3 HOURS

Instructions .1 Answer SIX questions only. THREE

Questions from each section 2. All questions carry equal marks.

3. Neatness in handwriting and clarity in

expression carries weightage 4. Illustration of an answer with clear

sketches / diagrams carries weightage

Q1. You have been appointed as Second Engineer of an older vessel which is in dry-docking and recently been purchased by your shipping company. Describe, in detail about your inspection, to ensure that the equipment on board ship related to safety equipment (related to firefighting and lifesaving) survey are satisfactorily complied with..

Answer:- (Note:- to write your answer within the time limit follow the tabular method given under to save time and yet complete the answer. Although ship is in D/D it is not within scope of D/D work.)

Assuming the ship is a bulk carrier, the checks i will carry out prior to the survey is given in tabular form as under

S . no

Group Equipment/item

Verify/check

1A documentation

Record of S/equipment

Update the record if any new items replaced(rec is with Master)

2A DO Muster list Update if any new crew joined as replacement

3A DO Safety plans

Check that all plans are in their locations and especially the plans which are kept in W/T tubes outside accommodation and are correct.

4B Water Hoses with couplings

In good condition and as per rec as well as safety plan. *1

5B ---DO -- Hose boxes

In good condition and as per safety plan

6B --DO-- Hydrants In good condition and as per safety plan *2

7B --DO-- Isolating valves

In good condition and as per safety plan *3

8B --DO-- Nozzles As per safety plan and rec. All in good condition.*4

9B --DO-- Drains As per safety plan and in good condition *5

10B --DO-- Intl shore coupling

2nos and stowed in location as per safety plan . *6

11B --DO-- G.S Pump In working condition *712B --DO-- Fire pump ----------DO----- *7

13B --DO-- Ballast pump

-----------DO-----*8

14B --DO-- Emergency fire pump

Location as per safety plan and in good working condition. *9

15B --DO--- Relief valve

Date when last set, to be tried out *10

16B --DO--- Fire main In good condition, no leaks

17C Portable fire extinguishers

Portable fire extinguishers 9 lt

As per safety plan and in good condition *11

18C --DO— Portable 45 lt

As per safety plan and in good condition.

19D Fire sensors accomodation

Heat sensors

As per safety plan, tested and found in working condition

20D --DO—IN E/R

Heat sensors

As per safety plan, tested and found in working condition.

21 D sensors in cargo holds

Smoke sensors

As per safety plan, tested and found in order.

22E Means of shutting of air

Ventilator flaps in cargo holds

As per safety plan , tested and found in good working condition.

23E --DO-- Accomodation doors to machinery space in all decks

As per safety plan , tested and found in good condition *12

23E --DO-- Accomodation doors to machinery space in all decks

As per safety plan , tested and found in good condition *12

24E --DO-- Sky light in E/R

In good working condition

25E --DO-- Funnel flaps

Tried out and working

26E --DO-- Blower flaps in E/R

In good working condition

27F Quick closing valves

Operated from emergency station outside E/R

All tested and found in good condition

28G Remote shut off switches

For oil burning equipment in E/R

All switches tested and found in working condition.

29H CO2

Equipment

alarm Tried out and in working condition *13

30H --DO-- MASTER V/V

Tried out and easy to operate

31H --DO-- Bottles Weighment due and is in progress

32H --DO— Connecting cables and piercers

In good condition

33I Personal gear

Firemans outfit

2 sets . both in good condition and stowed in location as per safety plan

34 I --DO-- S.C.B.A 3 SETS all in good condition and air bottles fully charged. Location as per safety plan

35I --DO-- N.A.Stretcher

In good condition . located in hospital

The above table gives the checks of all fire fighting equipment. Regarding the life saving appliances the checks on them will be carried out by the Chief officer and his staff. Regarding the fire pumps they have been tested before ship went into D/D .During stay in D/D the pumps cannot be tested. They may be tested when ship comes out of D/D

I have checked the lowering and hoisting of all lifeboats and have adjusted the centrifugal and hand brakes of all the winches (only two winches on the port side needed to be adjusted.). All the life boat engines are starting instantaneously and their batteries are fully charged. The reversing gears have also been tried out. The rescue boat engine has also been tried out

Additional information for guidance:-

*1 standard hose lengths vary from 15 M TO 22 M . the standard nominal dia is 64 mm. Minimum hoses required is L/ standard length of hose plus 50% extra

*2 good condition means that the hydrants can be opened and shut by hand (without wheel spanner ) and are not leaking from glands and in shut position.

*3 Isolating valves are not leaking in shut position and from glands and can be easily opened and shut.

*4 Jet nozzles are for deck and accommodation. For E/R use spray/ jet nozzles are to be used.

*5 Drains are provided on the fire main on the deck. They are to be kept open in cold weather to prevent ice formation in lines especially when ship is in latitudes beyond 300 north or south.

*6

*7 The f/s pump and G/s pump should be capable of giving a pressure 25 N / cm2 on the deck line with two hoses connected to two nozzles. The pumps should be capable of giving pressure on deck within 5 minutes on starting.

*8 The ballast pump should be capable of giving 40 N/cm2 on deck with two hoses and nozzles connected.

*9 The emergency fire pump is situated normally in the steering flat in the transom space. It has a self priming

device which is capable of priming the suction line in light load condition. This should be tried out .The pump should be capable of giving a pressure of 25N/ cm2 with two hoses and nozzles connected.

*10 The relief valve is set to about 50N/cm2 which ensures that the fire main is saved from excess pressure. Excess pressure happens if none of the hydrants are open and the pumps are on. It also gets activated if shore pumps are connected through the international shore coupling.

*11 All portable extinguishers are of 9 lt capacity. The approved types of portable extinguishers are :

(a) carbon-di-oxide -----water type ( to be used in accommodation and decks)

(b) Only carbon – di –oxide ( to be used for electric fires)

(c) chemical foam ( to be used for oil fires, mainly provided in machinery spaces.)

(d) Dry powder ( for electric fires )

The common checks are as follows ;

(1) to be pressure tested every 5 years.(2) Where Co2 cartridges are used they should be

checked for leaks and renewed accordingly.

(3) 100% spare charges should be available at all times.

(4) When portable extinguishers are used for demonstration or otherwise they should be charged immediately.

(5) Date of last pressure test and when charged should be painted on the body.

(6) All extinguishers must be provided with proper hooks and clamps so that they are never left on the floor without support.

*12 All accommodation doors situated on each deck leading to the machinery space are kept in open condition by a latch, which can be released simultaneously from the emergency remote station provided for quick closing valves and reote switches . This makes closing instantaneous.

*13 The Co2 alarm comes on as soon as the operating cabinet door is opened. It is a twin tone alarm and can be heard all over the accommodation and machinery space. The master valve and operating handle are within the cabinet

Q2. Sketch a high lift safety valve and seat detailing their special features; Describe how such a valve is overhauled and any clearance that should be measured and noted.

Answer:-

Method is as follows: The easing gear cable is disconnected from the easing gear. The easing gear is dismantled by opening the lever bearing keeps. The cotters connecting the caps to the spindles are removed after opening their locking devices and the caps taken out. Note position of both compression nuts by counting the counting the number of exposed threads and noting the same for future reference when assembling the valves.

Unscrew both compression nuts to relieve the springs of their compression. Dismantle the top cover along with compression nuts. Dismantle the Bonnet holding nuts and take out the bonnets along with spindles, springs, spring plates and attached valves. The valves can be dismantled from the spindles . the valves are in complete dismantled condition for inspection. Inspection of parts:- The inspection of the parts and suitable corrective action is as follows: The spindle should be checked for any bends and this can be verified exactly by centering and truing on the lathe. The springs should be checked for any deformity or permanent set and this can be done by comparing their heights and also comparing with the spare spring. Springs should be renewed if they are deformed or permanently set. The compression nut should be tried on the cover and checked for radial and axial play. If the nut is slack it should be renewed. Check the valve and valve seat for any cuts or ridges. Normally such defects do not occur since the valves very rarely open due to excessive pressure The valve requires light lapping using jeweller’s rouge. Ensure the drain hole and connecting drain pipe to the funnel scupper are both clear. The inspection being completed and suitable corrective action taken, the valves can be assembled after survey and compression nuts tightened to the original settings, The caps and easing gear will be assembled after he valves are floated(set) by the surveyor. The clearance normally measured is the compression ring clearance for setting the valve before final floating of the valves. However there can be situations where the valve and/ or valve seat are damaged by groove formation. The valve and/or valve seat will need machining to remove

the groove. This operation will alter the lip clearance and hence the lip clearance has to be measured. The method to find the altered lip clearance is not directly possible using a feeler gauge. Hence an indirect method is used whereby 4 lead balls made from lead wire available on board for clearance measurements is used. The balls are placed in four locatons under the lip as shown in the sketch (Fig.63) and compressed by the valve using the spindle , cover and gagging tool. The 4 balls are then taken out and their thickness measured using a vernier gauge. The average thickness is obtained which is the existing clearance. Assume this clearance is 2.7 mm. This clearance is to be increased to 3.2 mm which is done by adequately machining the valve lip accordingly

Q3. With regards to boiler water level control. Explain the following A. Shrink and swell phenomenon; B. Cascade control; C. Split control; D. Condensing chamber – Function and location.

Answer:- Repeat question. Refer to Q8 EKG AUG 2018.

Q4. With regards to steering control system. Explain following with the aid of suitable diagram. (a) Safematic concepts; (b) The flow reversal of main hydraulic pump and advantages; (c) The flow volume variation of hydraulic pump and method of achieve; (d) Hunting lever functioning.

Answer:- (a)The main safematic concept is the provision of the shock valves which allow the heavy swell to momentarily turn the rudder till the swell passes off and the rudder returns to its original position. This prevents damage ,by twisting , of the rudder stock.

Another safematic concept in modern steering systems especially the single failure concept system is the auto change over to the standby system if fracture of the pipes or any fault with the running system occurs. The change over occurs within 45 seconds of the break down.(b)The flow reversal helps in reversing the rudder movement without changing the direction of rotation of the pump an at constant running speed. Referring to the sketch given below it can be seen that when the floating ring connected to the pistons is at centre concentric with the suction and discharge manifold, no pumping action takes place. * when it is moved to the right it sucks from port A and delivers to port B. The distance moved

from the centre is proportional to the stroke of each pump and therefore proportional to the quantity delivered. * when it is moved to the left from centre it sucks from port B and delivers to port A, thereby reversal of flow has occurred. The quantity of flow is proportional to the distance moved same as in the previous case. (c) The advantage in variation of quantity or flow is also achieved by the distance the floating ring moves away from centre. Increasing the delivery rate which increases the rate of turn of the rudder.

(d)

Q5. A. With reference to fatigue of engineering components explain the influence of stress level at cyclical frequency on expected operating life.; B. Explain the influence of material defects on the safe operating life of engineering component; C. State the factors which influence the possibility of fatigue cracking of a bed plate transverse girder and explain how the risk of such cracking can be minimized.

Answer:- Repeat question Refer to Q5 EKG FEB 2018’

Q6. With respect to tankers describes: - A. How a pump room is ventilated? B. How cargo tanks are ventilated? C. Cargo tank

protection as per SOLAS 1974; D. Additional alarms provided for inert gas systems of the ‘inert gas generator’ type.

Answer:- (a) The pump room is ventilated by a powerful blower leading air from the blower suction placed on top of the pump room through ducting to the bottom of the pump room and spread out to the port and starboard sides by two branch ducts. In addition there are two exhaust blowers which connect the exhausts to the mast risers, so that the exhaust is discharged at a high level thereby preventing any risk of an explosion or fire.

(b)Cargo tanks are ventilated by high velocity vents during the loading operation and whilst on voyage they are ventilated by pressure/ vacuum valves.

(c)As per SOLAS 1974 the cargo tanks of both crude oil carriers and product tankers are to be inerted by inert gas produced in

an oil burning auxiliary boiler or an approved type oil burning gas generator. The equipment and the systems have to be approved by the Administration.

(d) The additional alarms to be fitted in the inert gas system are as follows:

(1) Blower failure alarm.

(2)High gas temperature alarm.

(3) Low gas pressure alarm and auto switch off.

(4) High gas pressure alarm and auto by-pass to atmosphere.

(5) High oxygen content alarm and auto switch off.

(6) High water level alarm in scrubber unit.

(7) Low water level alarm in scrubber unit.

Q7. Describe the possible faults which may be found during a dry-dock inspection of the following; A. Stern frame; B. Sea chest; C. Bilge keel; D. Anodes; E. Rudders.

Answer:- (a) Stern frame :- The stern frame is normally fabricated from steel plates and U channel section of steel of higher tensile strength and toughness, to which the hull strakes of the particular grade of steel are attached by welding and this is carried out in the hull shop during the construction stage. It is possible that inherent defects during the fabrication process may appear at a later stage during service, caused by locked

in stresses if proper welding sequence is not observed. These defects exhibit as cracks commencing from the junction of the welded joints as shown in the attached sketch

Another location is the welding at the aft coffin plate which can be cracked. This can be caused by the above stated reason as well that during the docking process this spot is subjected to a high concentrated reaction due to the trim that has been arranged.

Seachest:- After scraping off the barnacle growth and cleaning the chest,the chest plating must be gauged for its residual thickness especially if the ship is old. The chest must be painted internally with one coat of primer, two coats of finished paint and one coat of anti fouling paint. The anodes inside the box are to be renewed and the grating thoroughly cleaned ,refitted and all the stainless steel bolts locked by stainless steel wire.

Bilge keel:- Portions of damaged keel should be renewed.

Anodes:-All sacrificial anodes must be renewed even if some are not corroded. A good quality anode should be corroded completely by the subsequent dry docking.

Rudder:-The following inspections are carried out on the rudder:

(1) Rudder pintle clearances to be measured. If excessive the bushes are to be

renewed. Allowable clearance is 1.5 mm total for pintles upto200 mm dia, proportionally increased for larger diameters

(2) Jumping clearance to be compared against the clearance at tiller cross head, if clearance at cross head has increased, then the pedestal bearing has to be dismantled, built up by suitable welding and then machined to suit.

(3) The rudder bottom plug must be opened to check for water entry. If water has collected it means there is a crack or hole on the rudder plating. The crack or hole must be found out and suitably repaired and finally hydrostatically tested to prove that the repair is good.

Q8. With reference to oily water separators: - A. Describe with the aid of a sketch, the working of such a separator; B. Explain the consequence if the interface detector position is incorrect; C. Enumerate the various possibilities by which oil / water interface can be disturbed.

Answer:- (A) The sketched separator is an improvement of the simplex Turbulo oil/water separator to satisfy the more stringent requirement of limitation of oil pollution from E.R. bilges as specified in the amendment to MARPOL 73/78, when the limitation was reduced from 100 ppm to 15ppm.

In this separator the filtering chamber which has a two stage filter removes any small droplets of oil in the discharge and cause them to be held until they form larger droplets (coalesce. As they form larger globules , they rise to the oil collecting space..The rest of the operation is similar to the simplex turbulo separator.

(B) (b)If the interface position is incorrect, the oil can collected can be discharged into the sea, if the detector position is at the true water level, the water will be discharged in the oil collection tank(sludge tank), if the detector position is higher and is the true oil level.

(c) The various possibilities by which the oil/ water interface is disturbed is: * by over heating the oil water mixture whereby the mixture is boiling.

* In heavy sea condition due to pitching and rolling of the ship, the interface is disturbed.

Q9. A. State the advantages of using steam turbine propulsion power for vessels carrying LNG cargo. B. With regard to the use of L.N.G. cargo as boiler fuel explain: (i)The safety precautions relating to the gas pipeline supplying the boiler and burning the gas in the boiler, (ii) The means of getting rid of “excess gases” during loading or discharge.

Answer:- Repeat question. Refer to Q6 EKG FEB 2018 .