DieselShip's Online Content Library

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.

Q1. Explain the reason why the modern camshaft-less engines are known as intelligent engines. Describe briefly. The advantages and reliability of such an engine in comparison with the conventional marine diesels engines

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

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.

Q7. A. State, with reasons, THREE properties required of crankcase oil which is to be used for a trunk piston main engine.

B. Explain how a representative sample of crankcase oil would be obtained from a trunk piston engine. C. Briefly describe the action to be taken if the crankcase oil charge cannot immediately be replaced and analysis shows – (i) Water is present; (ii) Alkalinity has fallen; (iii) Viscosity has changed appreciably; (iv) Carbon content has increased.

Q9. A.  Difficulty has been experienced in maintaining engine speed at the set value; State THREE possible causes. State how each of these causes may be detected.

B. Describe the action to be taken in order to ensure safe operation of the main engine plant in the event of complete failure of the remote control and sensing equipment.

Q2. Explain with a sketch “speed droop” in a governor; Answer the following

A. How is a main engine governor different from an auxiliary engine governor?

B. Explain how load is transferred to an incoming generator explaining your actions with relation to the governor’s “droop line”.

Q7. A. Describe with aid of sketches the following types of bedplates as used for a large I.C. engine - i. Bedplate cast in section; ii. Fabricated steel Bedplate B. State the stresses to which these bedplates are subjected and explain how bedplates are secured to the hull of the ship.

Q8. A. Discuss the principal forces a large diesel engine crankshaft must withstand while in service and how the stresses resulting from these forces are kept within acceptable limits by good design and operation criteria; B. Discuss the manner in which the crankshaft may be overstressed and the consequences arising there from.

Q4. Misalignment of the main shafting between engine and propeller causes bearing overloads and shaft stress;

A. State the difficulties associated with checking shaft alignment and the reasons why results are unreliable due to external factors;

B. Explain with a simple sketch how a bearing load is assessed.

C. Explain how uneven loading could be rectified