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Q3. With reference to 2-Stroke Slow Speed Engine:

A. Sketch and describe Main Engine Exhaust Valve.

B. List out a procedure for test of Main Engine Exhaust Valve after overhaul.

Q2. a) Sketch a cylinder relief valve suitable for a large slow speed engine.

b) Describe its salient design features.

c) State the purpose of fitting such a device.

d) State the possible circumstances when the relief valve may lift and indicate the action to be taken to prevent damage to the engine.

Q3. With reference to the burning of heavy residual fuel in the main engine:

a) State with reasons FOUR modifications which need to be made as compared with the same engine burning distillate fuels.

b) State with reasons SIX properties you would require seeing in the specification for residual fuel indicating the effect EACH of these properties might have with respect to the storage and burning of the fuel.

Q4. Enumerate the causes of vibration in diesel machinery and shafting. Describe procedures by which it may be reduced by operating personnel, suitable design and devices. State the possible effects of vibration on machinery and crewmembers.

Q5. a) Describe how propeller shaft/stern bearing clearance is measured.

b) Identify with reasons the major factors which substantially determine the range of permissible clearance.

c) State with reasons what parts of propeller shafts should receive particularly close inspection upon withdrawal of such shafts for survey.

d) State why some propeller shafts require less frequent inspection than others.

Q1. Sketch and show all parts of a two-stroke engine stuffing box. Describe the procedure of overhauling two stroke engine stuffing box, without removing piston. Answer should include all safety precautions and necessary tools used for stuffing box overhaul.

Q7.a) What is the purpose of the main thrust bearing?

b) When checking the main thrust bearing, what dimensional checks would be necessary?

c) How is a thrust bearing cooled?

d) Describe, with a sketch, the special chocking arrangements normal to thrust bearing.

Q6. (a) Explain why highly efficient diesel engines tend to produce more NOx than low performance diesel engines.

(b) Describe, with the aid of a sketch, a Selective Catalytic Reduction (SCR) unit for a marine propulsion diesel engine.

(c) Explain why accurate monitoring of the exhaust gas flows entering and leaving a Selective Catalytic Reduction unit are required and how these readings are used to control the reduction chemical supplied to the SCR unit.

Q6. A. Sketch and describe a flywheel that would be fitted to a large marine diesel engine; B. Show in the sketches how it is fitted and secured; C. What is the purpose of the flywheel? Recently some engine makers have considerably reduced the size of the flywheel. Explain how this can be done.