EKG-Aug-21

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. With reference to the carriage and pumping of liquefied gas cargo: 

A. Sketch a suitable pumping system labelling the component parts; 

B. State; 

i) Why submerged hydraulically driven pumps are not used; 

ii) How overheating of pump drive shaft bearings is avoided; 

C. State, how the risk of fire and explosion in cargo tanks is obviated both in the loaded and discharged condition.

Q3. A. Describe the preparation necessary before the application (in dry dock) of sophisticated or approved long life coating to the underwater surface of the hull. B. State the significance of the roughness profile. C. List the different sophisticated coatings which are available.

Q4. With reference to radial lip seals for propulsion shafting : (a) Sketch and describe an outboard seal arrangement as fitted to an oil lubricating stern tube; (b) Explain, with reasons, the possible actions that should be taken in the event of loss of oil from the heater tank.

Q5. A. Sketch a watertight door and frame showing the manner of attachment to the bulkhead and the additional reinforcement carried by the bulkhead to compensate for the aperture. B. Explain how water tightness of the door and frame mating surfaces is ensured with hydrostatic pressure tending to force the faces apart. C. (i) Describe the means of closing the door; (ii) State the number of closing stations and the position of each.

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 6(a).

Q7. A. Describe the procedure to be adopted for the inspection of a safety valve fitted to an exhaust gas boiler stating, with reasons, which parts should receive particularly close attention. 

B. Describe the procedure for the setting of safety valves of exhaust gas-fired auxiliary boilers; 
C. Explain the action taken after the setting of safety valves as in (B).

Q8. A. Explain Creep; Brinelling; Fretting; Fretting corrosion; B. State, with reasons, where these may occur in ship propulsion System.

Q9. With reference to electro-hydraulic steering gears: 

A. Explain in terms of control parlance, the function of the “Hunting gear”; 

B. Explain the consequences if the standby pumping unit has motored; 

C. State TWO methods employed to prevent the standby hydraulic pump from being motored by the operating unit.