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Q3. A. With reference to the underwater surface of a ship’s hull; i. Describe a hull plate roughness analyser system;

ii. State the significance of the roughness profile and compare the typical roughness values for a new ship and a ship eight years old;

B. Which reference to the application of self-polishing paint in dry dock - i. Describe the plate preparation necessary;

ii. State the defects that may occur in the paint coating if it is not correctly applied.

Q2. Sketch a schematic diagram of a ship showing principal dimensions used in ship design and define them.

Q5. A palm of the rudder of a vessel requires extensive welding repairs and as a Chief Engineer you are requested to supervise –

A. Suggest a suitable type of welding process;

B. State with reasons FOUR common welding defects that can occur there;

C. State what tests may be carried out before returning the rudder to service.

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. Sketch and describe the various methods of representing the hull form.

Q6. A. What factors influence the frictional resistance of a ship and what formula is used to calculate the resistance? B. A ship of 12000 tonne displacement has a rudder 15m2 in area, whose centre is 5m below the waterline.  The metacentric height of the ship is 0.3m and the centre of buoyancy is 3.3m below the waterline.  When travelling at 20 knots the rudder is turned through 30 .  Find the initial angle of heel if the force Fn perpendicular to the plane of the rudder is given by:  Fn=577 Av2 sin  N, Allow 20% for the race effect.

Q7. Derive an expression for the blade element efficiency using the blade element theory.

Q8. A. Describe the procedure for speed, Power and fuel consumption trials. B. An oil tanker has LBP 142m, beam 18.8m and draught 8m. It displaces 17000 tonne in seawater of 1.025 1/m3. The face pitch ratio of the propeller is 0.673 and the diameter 4.8m. The results of the speed final show that the true slip may be regarded as constant over a range of speeds of 9 to 12 knots and is 35% the wake fraction may be calculated from the equation: W=0.5Cb = 0.05. If the vessel uses 20 tonne of fuel per day at 12 knots and the consumption varies as speed. Find the consumption per day at 100 rev/min.

Q9. Derive an expression for the free surface effect. How does vertical and transverse location of a slack tank can affect the free surface effect? Describe the methods employed to reduce the free surface effect.

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.