DieselShip's Online Content Library

Q1. (A) Explain how wear on bearing surfaces is effected by each of the following factors:

(i) Dissimilarity of materials in the contact surfaces

(ii) Relative speed of sliding between the surfaces

(iii) Roughness of the surfaces

(iv) incompatibility of lubricant and bearing material.

(b) Describe how each effect may be identified during inspection, Suggest corrective action at either operational or maintenance stages. (16)

Q2. Cast iron is most widely used metal after steel in Marine Engineering. Most cast irons consist of graphite in steel like matrix. Discuss the variation of properties that may arise with reference to pearlitic grey cast iron and spherical grey cast iron. Describe briefly the treatment necessary to produce these two types of iron.

Q3. a) Explain why pilot injection is required for a Dual fuel engine when burning natural gas.

b) Describe, with the aid of a sketch, the arrangements for a dual fuel engine which is capable of burning natural gas on

a) The Otto cycle.

b) The Diesel cycle. (16)

Q4. Reverse osmosis is the modern alternative for shipboard production of drinking water.

(a) Describe using simple diagrams if necessary, the principle of reverse osmosis. (8)

(b) Sketch a line diagram showing a single pass system for producing fresh water from sea water and describe the system. (8)

Q5. With reference to Gear pumps used for lubricating oil transfer.

(a) Sketch and describe a gear type pump indicating the flow of fluid. (6)

(b) State the materials that gear type pump components may be manufactured from. (4)

(c) Specify THREE applications that are suitable for the employment of gear type pumps. (6)

Q6. With reference to Air-conditioning System onboard your vessel:

a) Sketch and describe a high-pressure cut-out in a refrigeration system. (6)

b) The refrigeration compressor has stopped due to operation of the H.P. cut-out. (4)

Explain: (i) The possible causes.

ii) How these causes would be found and possible remedies.

c) What steps are taken if the compressor “Short-cycle” on low pressure cut-out? (6)

Q7. With regards to process control system explain following: (16)

A. Proportional control.

B. Integral control.

C. Derivative control.

D. The necessity of derivative control.

Q6. With regards to main transmission shaft flange coupling arrangements:

A. Sketch a hollow type coupling bolt and the hydraulic head/nut and loading rod which are used to fit it.

B. Describe how the bolt is fitted.

C. State the advantage of the hollow coupling bolt as compared to the traditional type of coupling bolt.

Q9. With reference to electrohydraulic steering gear systems with four rams. (16)

(a) With the aid of a sketch describe the working principle of hydraulic pump.

(b) Explain the method adopted to prevent hydraulic oil leakage along the rams.

(c) Discuss the methods adopted to prevent damage to the steering gear due to jumping of rudder in heavy seas.