EKG-Mar-20

Q1. Cast iron is most widely used metal after steel in Marine Engineering. Most cast irons consist of graphite in steel like matrix. Discuss the variation of properties that may arise with reference to pearlitic grey cast iron and spherical grey cast iron. Describe briefly the treatment necessary to produce these
two types of Irons.

Q2. With respect to properties of fuel oil, explain the significance of the following terms;

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

Q3. With regard to 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 crank case lube oil of a slow speed main engine?

Q4. As second engineer onboard a tanker, describe the procedure for presenting a Main Boiler for survey by a classification society.

Q5. With regards to main transmission shaft flange coupling arrangements: 

A. Sketch a hollow type coupling bolt and the hydraulic head/nut and loading rod which are used to fit it; 
B. Describe how the bolt is fitted; 
C. State the advantage of the hollow coupling bolt as compared to the traditional type of coupling bolt.

Q6. Sketch and describe the operation of four ram electro-hydraulic steering gear system. Indicate and explain the valve position for the operation of the system when one pump is isolated and unit is operating on two rams only.

Q7. With reference to Vacuum Sewage System:

(i) Sketch & Describe a Vacuum Sewage System.
(ii) State the advantages of Vacuum Sewage System.
(iii) State the different causes of dropping vacuum.

Q8. Detail the desirable properties of a refrigerant. Make a table and compare following refrigerants for use in a provision cooling plant for a 50000 DWT Oil tanker: R-22, R-134a.

Q9. Sketch a sealing arrangement for an oil lubricated stern tube. Identify the common forms of seal failure; State how oil loss due to seal failure can be restricted whilst on passage? What is the material used for sealing rings and propeller shaft liner?