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Q4. Explain each of the following:

A. Why wear down in main bearings is critical to the condition of the crankshaft and propeller shaft system.

B. Why total reliance is placed on frictional grip in conventional built up crankshaft

C. Why hole oils are given large fillets in crankpin and journals.

Q2. Explain EACH of the following; A. Effect of worn out main bearings on the condition of the crankshaft and propeller shaft system

B. The reliance on frictional grip in conventional built up crankshaft. C. The reasons for providing large fillets to oil holes in crankpins and journals

Q6. With reference to bridge control of a large slow speed propulsion engine.

A. How is starting and reversing achieved?

B. Investigate and suggest remedial action required if the engine,

(i) Fails to turn on air.

(ii) Turns on air but fails to fire on fuel;

(iii) Fails to reverse.

Q4. A. Explain the possible reasons T/C vibration while operating at a steady speed.

B. State how the incidence of turbo charger vibration might be minimized.

C. Explain the action to be taken in order to maintain 2 stroke engine operation in the event of turbo charger having to be taken out of service.

D. Indicate the effect this action will have on engine operation.

{How is the engine operation affected when operated with a by-passed T/C}

Q5. With reference to the crankshaft and running gear of an engine, explain static balance, Dynamic balance, Torque reaction couple, and Critical speed

Q8. (a) Describe, with the aid of a sketch, the main engine auxiliary equipment for automatic monitoring and regulation of the fuel viscosity.

(b) Explain the operation of the system, which incorporates the equipment described in Q.8(a).

(c) For an engine which is maneuvered on distillate fuel but operated on heavy residual oil at sea, static, as second engineer, the standing orders you would issue for the procedure to be adopted when changing form distillate fuel to heavy residual oil and vice versa.

Q9. With reference to timing chains:

A. State the cause of chain elongation in service, using a sketch of a section of a camshaft roller chain to illustrate your answer;

B. State: i. The effects of increased chain length:

ii. The method of assessing percentage increase in length:

C. Explain how the effects of elongation are corrected:

D. State why a limit is placed on percentage chain elongation and give typical example.

Q8. With reference to bottom end bolts for medium speed four stroke engines:

A. Explain why bottom end bolts will ultimately fail under normal operating conditions;

B. Identify the features incorporated into bolt design to inhibit failure;

C. Explain how bolt failure may be hastened when maintenance is carried out;

D. Describe, as Second Engineer, your strategy for preventing bolt failure.

Q5. With reference to crankcase diaphragm glands: Explain why effectiveness deteriorates in service.

A. Describe the procedure for renewal of parts so that efficiency is restored. (6)

B. Describe how effectiveness is restored if spares are unavailable. (5)

C. Explain the functions of the upper and lower sections. (5)

Q8. During the past 4 months since you have joined the ship as second engineer a number of main engine exhaust valves have suffered cracking and corrosion at the seating faces. Write a report to the superintendent covering the following points;

A. An explanation detailing how the problem became evident.

B. Your action upon recognising the extent and seriousness of the problem

C. Your reasoned views regarding the positive causes of the problem

D. Your recommendations to avoid future incidents.