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Q4. Fatigue is one of the main causes of crankshaft failure.

A. Indicate on a Sketch the most likely location of a fatigue crack;

B. How is a fatigue failure is identified;         C. Describe initiation of a fatigue crack;

D. Sketch and Describe the methods used to inhibit fatigue cracks

Q2. Sketch a Main Engine air starting distributor and describe how it operates.

List the safety devices and interlocks incorporated in main engine air starting system and state the purpose of each.

Q8. How are large slow speed engines structured to withstand the following forces?

A. Forces due to combustion load;

B. Guide forces;

C. Inertia forces.

Q7. With reference to the 4-stroke medium speed engines:

A. Define the cause and effect of thermal stressing in cylinder Heads, liners and pistons.

B. Explain why thermal stressing are aggravated with increase in cylinder bore.

C. Explain how stress concentration and its effects are relieved by maintenance and operational practices.

Q6. With reference to piston rings;

A. State the reasons for breakage;

B. How maintenance and engine operation could minimize breakage;

C. Explain the recent developments in the piston rings to minimize breakage;

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.

Q7. With reference to medium speed engine cylinder liners:

A. Explain the cause and effects of Polishing or glazing;

B. Describe, with the aid of sketches, an anti-polishing ring and how it is fitted in the liner;

C. Explain the action of anti-polishing ring during the operation of the engine.

Q2. A. Outline the problems associated with improper lubrication of the liner and piston assembly of a large slow speed engine.

B. Describe and state the causes of each of Clover leafing and Micro-seizure

C. List out the composition of a cylinder oil suitable for an engine operating on VLSFO.

Q5. With reference to mechanical/hydraulic governors explain:

A. Why flyweights are driven at a higher rotational speed than the engine;

B.  How dead band effects are reduced;

C.  How hunting is reduced;

D.  How the output torque is increased.