EKG-July-21-(1)

Q1. With reference to hydraulic steering gears, sketch and describe each of the following:

(A)Single failure concept;
(B)100% redundancy.

Q2. A. With reference to fatigue of engineering components;

A. Explain the influence of stress level at a cyclical frequency on expected operating life.;
B. Explain the influence of material defects on the safe operating life of engineering components;
C. State the factors which influence the possibility of fatigue cracking of an auxiliary boiler feed water pump shaft and explain how the risk of such cracking can be minimized.

Q3. 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).

Q4. How the ingress of seawater is prevented in an oil-lubricated stern bearing system. Should the system fail, describe the corrective action possible whilst the vessel is afloat? State the reasons for fitting two stern bearing oil header tanks in some cases?

Q5. A. Describe a transverse bow thrust unit using CPP, mention how it should be made to support and how the strength of thrust and reverse thrust are achieved;

B. State with reasons, a suitable prime mover for the controllable pitch propeller;
C. State whether the thrust unit delivers a relatively low-pressure head with high volume output or a high-pressure head with low volume output.

Q6. With respect to the properties of fuel oil, explain the significance of the following terms;

(a) Calculated Carbon Aromaticity Inbox (CCAI).
(b) Open flash point and Closed flashpoint.
(c) The importance of Sodium to Vanadium Ratio.
(d) Octane Number.

Q7.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

Q8. With respect to refrigeration gases used on-board vessels, answer the following: 

A. Explain the Ozone Depleting Potential of conventional refrigerant gases. 

B. Name the alternate refrigerant gases available and being used onboard. 

C. What are the steps are taken to minimize the release of refrigerant gases from the plant during normal operation and maintenance activities?

Q9. With reference to Flue gas Inert gas system:

A. Sketch and describe using a line diagram showing a typical 'Inert Gas System' used for inerting the cargo tanks of oil tankers, labelling the component parts.
B. State what oxygen content you would expect in the flue gases if good combustion is achieved.