DieselShip's Online Content Library

Q1. (a) Sketch and describe the construction and working principle of an air staring valve used in a two-stoke main engine. (10)

(b) Discuss common faults associated with air staring valves, their possible consequences, and maintenance or safety measures taken to ensure reliable operation. (6)

Q2. (a) Explain the purpose and working principle of the Load Dependent Cooling System (LDCS) in a two-stroke main engine. With the help of a diagram, describe how the system varies cooling water flow with engine load. (10)

(b) Discuss the advantages and disadvantages of using a load dependent cooling system over a conventional constant flow cooling system. What issues may arise if the system malfunctions. And how are they addressed? (6)

Q3. With reference to the Crosshead of Large two-stroke engines:

A. Explain how crosshead and guide shoe clearances are checked, in large 2 stroke engines. (8)

B. Explain how crosshead alignment is checked and adjusted. (8)

Q4. (a) Describe the different types of cams used in marine main engines. Explain their functions and how the cam profile affects the operation of exhaust valves, fuel pumps, and starting air systems. (10)

(b) What is a negative cam? Explain its purpose, constructional features, and where it is typically used in main engine. (6)

Q5. Describe briefly the methods of carrying out a bend test and an impact test. Illustrate the general form of the test pieces used and state how the final results are given for comparison of different materials. Of what practical use are the figures obtained? (16)

Q6. a) Describe the inspection, which is required to be carried out in the dry-dock after the stern of a ship has heavily struck a dock wall. (8)
b) The propeller is found to be damaged, and it is decided to fit the spare propeller. Describe the process and mention the precautions to be taken to ensure correct assembly. (8)

Q7. During the overhaul of medium- speed auxiliary diesel generator you find that the white metal of one of the bottom end bearings has cracked. Explain how you would fit a spare bearing and enumerate the various tests you would carry before putting the machine back into service. (16)

Q8. With reference to the exhaust gas boiler of your ship explain the following:

A. Composition and reasons of soot deposits.

B. Various stages of soot fire leading to high temperature fire.

C. Procedure to be followed for firefighting under different stages of soot fire.

D. Actions required prior to dry running of an exhaust gas boiler.

Q9. a) Describe the routine and preventive maintenance procedures carried out on a plate-type cooler used on ships. Explain the steps involved in dismantling. Inspection, cleaning, and reassembly of the plates. (8)

b) Explain the procedure for detecting internal leakage in a plate -type cooler. What are the indications of leakage during operation, and how can they be confirmed during maintenance?  (4)

c) Describe the backflushing procedure for a plate-type cooler when is it recommended, and how does it help in maintaining the efficiency of the heat exchanger. (4)