DieselShip's Online Content Library

Q1. (a) What is a gear pump and how does it differ from other types of positive displacement pumps used onboard? (8)

(b) State FOUR advantages of using gear pumps in shipboard lube oil systems compared to centrifugal pumps. (8)

Q2. Which of the following would cause a drop in the output (production rate) of a fresh water generator? (16)

(a) Increased jacket cooling water temperature.

(b) Fouling/Scaling of the heating plates.

(c) Higher vacuum in the evaporator shell.

(d) Increased seawater flow through the condenser.

Briefly justify your answer with the operating principle of a plate type fresh water generator.

Q3. Why is a speed droop governor preferred for auxiliary marine generator engines over an isochronous governor? (16)

(a) Droop allows the engine to operate at a perfectly constant speed regardless of the load.

(b) It automatically activates the auxiliary engines during blackouts.

(c) It allows for stable load-sharing between alternators operating in parallel.

(d) Droop limits the maximum torque output of the engine.

Select the most appropriate answer and briefly explain the droop action of a governor.

Q4. A main air compressor interstage air-cooler has burst. Put down a logical sequence of event that could have caused this accident. Put down your analysis, point by point and complete in technical detail (16)

Q5. (a) Explain the function of an 'eductor' with the aid of a sketch. Where do you find an eductor system on a ship? Give two examples. (8)

(b) Explain the working principle of an eductor. What are the operational challenges that may affect the performance of the eductor? (8)

Q6. Write short notes on the following: (16)

(a) The need to monitor temperature of fuel in service tanks

(b) The need to constantly monitor soundings of double bottom tanks

(c) The importance of keeping bilges free of oil and other residues

(d) The importance of ensuring proper ventilation of the engine room

Q7.a) Explain why air receivers should be drained frequently and its internal surfaces to be provided with protective coatings (6)

b) Describe the procedure for internal inspection of air receivers and the possible defects that may be encountered. Suggest suitable repair methods for the defects. (6)

c) Describe fault conditions associated with air receiver mountings and the remedies to rectify the same. (4)

Q8. Sketch and explain the construction of a feed Check Valve. Why is it known as double shut off arrangement. (16)

Q9. What is the primary function of the Inert Gas System (IGS) on a modern oil tanker? (8)

(i) To increase cargo discharge speed.

(ii) To maintain the temperature of heavy crude oil.

(iii) To prevent explosions in cargo tanks by maintaining a low oxygen environment.

(iv) To eliminate static electricity in the pump room.

Briefly justify your answer.

(b) With a line diagram, indicate the safety equipment installed within the Inert Gas system of a tanker ship and explain the function of at least two equipment. (8)

Q1. (a) Sketch a screw displacement pump and explain its operation. (10)

(b) State the factors which affect its efficiency. (6)

Q2. The by-products of oxidation, as a result of water contamination of hydraulic oil are generally: (16)

(a) Removed by cellulose type filters

(b) Gums, varnishes, and acids

(c) Always neutralized by oil additives

(d) Harmless and have no effect on system components; Briefly justify your answer.

Q3. a) Bunkering as a shipboard operation has its own significance. List out the important inspects of a bunkering operation including the preparation and precaution to be taken to ensure a safe operation. (8)

b) What does the Bunker specification include and how does it affect the engines adversely? Name at least three such ingredients that you expect in a Heavy Fuel Oil bunker and the effects on the engine operation. (8)

Q7. a) What are the safety devices fitted to an Air Compressor? (4)

b) What is the purpose of the Scum Valve on a Boiler? (4)

c) What is the function of an Evaporator in a Refrigeration System? (4)

d) Regarding the Emergency Bilge Injection Valve, what is its relevant size compared to the Main Sea Water Injection Valve? (4)

Q5. (a) Draw a simple line sketch of a 'shell and tube' cooler, clearly labelling its parts. (6)

(b) Describe the system. (4)

(c) Name common defects found. (3)

(d) What periodical maintenance needs to be carried out. (3)

Q6. (a) Why Engineering Materials are tested prior manufacturing of their components. (6)

(b) Describe the various destructive and non-destructive tests carried out on materials for shipboard used. Explain the purpose of each test and where the same applied. (10)

Q7. A LT cooler of the centralized cooling water system on your ship is showing poor performance. What measures you would initiate to rectify the problem and improve the performance. (16)

Q8. Explain how each of the following conditions contribute to the satisfactory performance of oil centrifuges.

(a) Correct bowl speed (4)

(b) Cleanliness of bowl (4)

(c) Low rate of feed to bowl (4)

(d) Contaminated oil allowed to stand for an appreciable time prior to centrifuging. (4)

Q9. With reference to control system state, explain in brief:-

a) Two step action. (6)

b) Proportional control. (5)

c) Offset. (5)