NAVAL MEO Class 2 Written Question (FEB 2023)

EXAMINATION OF MARINE ENGINEER OFFICE

NAVAL ARCHITECTURE

    M.E.O. CLASS II

       Time: 3 HOURS Total Marks - 100

Q1. With reference to membrane tanks for the carriage of liquefied gas at very low temperatures.

A. Describe with a sketch one method of building up the insulation; B. State which alloy is used for the membrane and the reason; C. Explain why a secondary barrier is installed. i) Longitudinally; ii)Transversely.

Q2. With reference to the prevention of hull corrosion discuss:

A. Surface preparation and painting of new ship plates.

B. Design of the ships structure and its maintenance.

C. Cathodic protection by sacrificial anodes, of the internal and external areas of the ship.

Q3. With reference to fatigue of engineering components explain the influence of stress level and cyclical frequency on expected operating life;

A. Explain the influence of material defects on the safe operating life of an engineering component;

B. State the factors which influence the possibility of fatigue cracking of a bed-plate transverse girder and explain how the risk of such cracking can be minimized.

Q4. A. Describe a method of the attachment of bilge keels;

B. State THREE reasons for not extending bilge keels the entire length of the vessel;

C. Evaluate the effectiveness of bilge keels for large wall sided vessels;

D. Explain TWO principles of roll damping those bilge keels exploit.

Q5. A. Describe the double bottom and framing arrangement used in the machinery space to cope up with the concentrated loads and vibration, together with shaft and thrust block support.

B. Give reasons for the choice of thrust block position.

Q6. A. Describe how water tightness is maintained where bulkheads are pierced by longitudinal beams or pipes.

B. A triangular bulkhead is 7 m wide at the top and has a vertical depth of 8 m. Calculate the load on the bulkhead and the position of centre of pressure if the bulkhead is flooded with sea water on only side:

(i) to the top edge, (ii) with 4 m head to the top edge.

Q7. A. Explain the effect on GM during the filing of a double – bottom tank

B. An oil tanker 160m long and 22m beam floats at a draught of 9m in seawater. Cw is 0.865. The midships section is in the form of a rectangle with 1.2m radius at the bilges. A midships tank 10.5m long has twin longitudinal bulkheads and contains oil of 1.4 m3/t to a depth of 11.5m. The tank is holed to the sea for the whole of its transverse section. Find the new draught.

Q8: A. What is meant by the Admiralty Coefficient and the Fuel Coefficient?

B. A slip of 14900 tonne displacement has a shaft power of 4460 Kw at 14.55 knots. The shaft power is reduced to 4120 kW and the fuel consumption at the same displacement is 541 kg/h. Calculate the fuel coefficient for the ship.

Q9. A. Describe how the distribution of mass within the ship affects the rolling period;

B) The 1⁄2 ordinates of a water plane at 15m intervals, commencing from aft, are 1, 7, 10.5, 11, 11,10.5, 8, 4 and 0m. Calculate:

(a). TPC;

(b). Distance of the centre of flotation from midships.

(c). Second moment of area of the water plane about a transverse axis through the centre of flotation.