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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 Irons.

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.

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

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.

Q1. Sketch a sealing arrangement for an oil-lubricated stern tube. Identify the common forms of seal failure; State how oil loss due to seal failure can be restricted whilst on passage? What is the material used for sealing rings and propeller shaft liner?

Q8. A. State the advantages of using steam turbine propulsion power for vessels carrying LNG cargo. B. With regard to the use of L.N.G. cargo as boiler fuel explain: (i)The safety precautions relating to the gas pipeline supplying the boiler and burning the gas in the boiler, (ii) The means of getting rid of “excess gases” during loading or discharge.

Q9. Misalignment of the Main shafting between engine and propeller causes bearing overloads and shaft stress.

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

b) State the reasons for misalignment

c) Explain with a simple sketch how a bearing load is assessed.

d) Explain how uneven loading could be rectified

e) Why wear down in main bearings is critical to the condition of the condition of the crankshaft and propeller system.

Q6. A. Sketch a line diagram showing the layout components of a hydraulic system with a variable delivery, Pressure compensated pump and accumulator, suitable for the operation of deck machinery.

B. Describe the operation of the system sketched in part 6 (a).

Q2. State with reasons, how cracking in EACH of the following location is caused, rectified and avoided

a. “A”-frame.    b. Bedplate longitudinal girder.            c. Bed plate transverse girder.

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 Inert Gas Generator fitted on gas carriers:

a. Sketch a line diagram showing a typical 'Inert Gas System' used for inerting in gas carriers, labelling the component parts. (6)

b. Describe the system. (5)

c. State the function of a chiller used in this type of inert gas generator. (5)