DieselShip's Online Content Library

Q2. With reference to the carriage and pumping of liquefied gas cargo:

A. Sketch a suitable pumping system labelling the component parts;

B. State;

i) Why submerged hydraulically driven pumps are not used;

ii) How overheating of pump drive shaft bearings is avoided;

C. State, how the risk of fire and explosion in cargo tanks is obviated both in the loaded and discharged condition.

Q1. A. Explain the ideal design requirements of a ships propeller; B. briefly describe the propeller maintenance that should be carried out to prevent the fuel being wasted.

Q8.a) Explain with a sketch the operation of an automatic expansion valve as fitted in the direct expansion refrigeration plants. How is this valve adjusted?

b) Explain how critical temperature restricts plant operation and how these limitations can be overcome?

c) Explain how this system maintains the provision rooms at different temperatures?

Q4. With reference to hull cathodic protection systems of the impressed current type:

A. Sketch and describe such a system;

B. Explain how protection may be ensured for the rudder and propeller;

C. State any precautions that should be taken when this type of system is installed.

Q1. Discuss the causes of vibration and noise in main gearing and describe detrimental effects on machinery and operating personnel. How would you detect the source(s) of this vibration and how might it be reduced to tolerable limits?

Q9. (a) Explain electro chemical reactions and the difference between oxidation and reduction electrochemical reactions with examples. Which reactions occurs at the anode and cathode?

(b) Explain galvanic corrosion and discuss the different procedures to prevent it.

Q6. State why the temperature of lubricating oil supplied to an engine needs close control. Sketch and describe an arrangement and explain the principle of operation of instrumentation and control equipment for automatically maintaining the temperature of lubricating oil supplied to an engine at its desired value

Q5. A. Sketch a simple cross section through a single stage centrifugal pump with a fully shrouded single entry impeller, name the components of the pump and indicate the direction of fluid flow. B.  Describe: - i. The function of the impeller and how suction is created by it; ii. The function of the volute casing. iii. State the material of each component of the pump. C. State the suction lift that may be expected.; D. State why some centrifugal pumps have: - A double volute casing; (ii) A diffuser ring

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.