EKG-Nov-20

Q1. With regard to the care of lubricating oils on board answer the following –A. What is microbial degradation of lubricating oil and how is it prevented? What methods are employed to ensure correct sampling for shore-based testing?
B. What action will you take If the testing results show abnormal values of water content and TBN for crankcase lube oil of a slow-speed main engine?

Q2. You have recently joined a vessel as Second Engineer Officer. For the past several voyages it has been the practice on board to dispense with the use of the exhaust gas boiler and leave it to run dry. As part of an overall economy, drive company has requested you to re-commission the boiler. Write a letter to the Superintendent Engineer stating how the boiler was brought online and the safety valves adjusted.

Q3.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?

Q4.With reference to reciprocating air, compressors explain why; A. Clearance volume is critical to efficiency; B. Spring-loaded plate valves are invariably used; C. Compression is accomplished in apparently unequal stages; D. Inter cooling is used between stages.

Q5.With regard to refrigeration system explains; 

A. What are the possible reasons for HP cut out in the refrigeration system? 

B. What are the indication if the air is present in the refrigerant system and how to remove air from the refrigeration system? 

C. How unloader works in the refrigeration system? 

D. What are the possible reasons for Icing on evaporation coil? 

E. Why compound gauge fitted in the refrigeration system?

Q6. Reverse osmosis is the modern alternative for shipboard production of drinking water.

A. Describe using simple diagrams if necessary, the principle of reverse osmosis.
B. Sketch a line diagram showing a single pass system for producing freshwater from seawater and Describe such a system.

Q7. A. Explain Creep; Brinelling; Fretting; Fretting corrosion; B. State, with reasons, where these may occur in ship propulsion System.

Q8. With reference to Vacuum Sewage System:

(i) Sketch & Describe a Vacuum Sewage System.
(ii) State the advantages of the Vacuum Sewage System.
(iii) State the different causes of dropping vacuum.

Q9.Compare the destructive testing done on engineering materials with non-destructive testing done on engineering components. Briefly describe one destructive test and two non-destructive tests to illustrate your answer