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Q8. A. Explain the action of EACH of the following metallurgical mechanism:

(i) Creep;          (ii) Brinelling;   (iii) Fretting;     (iv) Fretting corrosion;

B .State, with reasons, where EACH of the mechanisms in occur in ship propulsion System.

Q3. Sketch and describe a boiler water level controller of the float operated type. State the reasons for having this mechanism on the boiler and using this controller and boiler for analogy explain the following terms.

A. Detecting element

B. Servo motor

C. Desired Value

Q1. With regard to care of lubricating oils onboard, answer the following:

(a)  Microbial degradation of lubricating oil and measures to prevent the same

(b)  Methods of ensuring correct sampling is done for the purpose of shore based testing.

(c)  If the shore based testing results show an abnormal values of water content and TBN for the crank case lub oil of a slow speed main engine, what will be interpretation and subsequent action?

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.

Q6. Sketch and describe a “fail safe steering gear” suitable for use on a tanker of more than 100,000 T dwt; Explain the sequence of events that take place when an oil leak takes place in one of the hydraulic pipe lines.

Q9. Describe with a sketch a pneumatic relay and show how feedback can be achieved when such a relay is used in conjunction with a flapper mechanism. (16)

Q5. With respect to refrigeration gases used on-board vessels, answer the following:

A. Explain Ozone Depleting Potential (ODP) and Global warming potential (GWP) of conventional refrigerant gases. (7)

B. Name the alternate refrigerant gases available and being used onboard. (4)

C. Explain the steps you will take to ensure that release of refrigerant gases from the plant in minimized during normal operation and during maintenance activities. (5)

Q5. A. State why fixed pitch propellers have a poor efficiency when going astern.

B. With reference to controllable pitch propellers state:

i. Why is it preferable that the main servomotor be housed in the propeller hub rather than in the shafting forward of the propeller shaft?

ii. What regular maintenance and checks should be carried out to ensure maximum reliability of the gear at all times?

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)