DieselShip's Online Content Library

Q1. With reference to automatic sprinkler system for firefighting purposes:

a) Explain, with the aid of a heat release versus time diagram, the difference between fire control and fire suppression

b) State the limitations of using glass bulb to activate sprinkler heads and suggest, with reasons, an alternative mechanism

c) The safety devices incorporated in the system

d) The parameters governing the volume of the pressure tank

Q2. a) Define creep and specify the conditions under which it occurs?

b) Discuss three metallurgical processing techniques that are employed to enhance the creep resistance of metal alloys

Q3. a) Explain why pilot injection is required for a Dual fuel engine when burning natural gas.

b) Describe, with the aid of a sketch, the arrangements for a dual fuel engine which is capable of burning natural gas on;

    a) The otto cycle

    b) The Diesel cycle.

Q4. (a) Describe, with the aid of a sketch, an open loop system for reducing SOx emissions from engine exhaust gas, explaining how the system operates whilst the vessel is in open waters.

(b) Describe, with the aid of a sketch, a closed loop scrubber system for removing SOx from engine exhaust gas, explaining the operation of this unit and stating when it would be used.

Q6. Hydrogen damage is a general term used for mechanical damage of metal caused by the

presence of hydrogen, briefly discuss the different types of hydrogen damage and how these damages can be prevented?

a) Hydrogen blistering (4)

b) Hydrogen embrittlement (4)

c) Decarburization (4)

d) Hydrogen attack (4)

Q6. With reference to keyless propellers explain:

a) Why keys and keyways have been eliminated

b) How angular slip is avoided

c) Why mounting upon and removal of a propeller shaft requires a different technique than that employed for propeller with keys.

d) State with reasons why use of wedges and jacks are not advisable when removing the propeller from its shaft

Q9. With reference to main boiler super heater arrangements:

A. Compare the advantages and disadvantages of contra flow with parallel flow design.

B. Describe how the element tube banks are supported yet allow for expansion.

C. Describe how boiler carryover affects super heater effectiveness and condition.

Q8. In a Rotary vane steering gear, briefly state.

a) How are the fixed and moving vanes attached to cylinder and rotor respectively.

b) How many sets of vanes are provided? What is the limitation factor to number of vanes.

c) How is strength imparted to moving vanes to enable them to act as rudder stops?

d) How is rudder uplift accommodated?

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.