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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.

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.

Q3: Foreign going vessels are required to possess a valid safety equipment certificate renewed at intervals after survey of the safety equipment.

A. Compile a list of items that are contained in the safety equipment survey. (8)

B. From the list compiled in (a) select TWO ship systems, explain now they would be examined and identify possible defects. (8)

Q5: 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.

Q5. With reference to ship’s rudder state:-

Why can a breached hollow rudder add to fuel costs? (6)

Why excessive pintle clearance should not be tolerated? (5)

Why fitted bolts are used in connecting upper and lower stocks? (5)

Q6. A. Describe the stability requirements of a ship for dry-docking.

b) A ship of 12000 tonne displacement has a rudder 15 m2 in area, whose centre is 5 m below the waterline. The metacentric height of the ship is 0.3 m and the centre of buoyancy is 3.3 m below the waterline. When travelling at 20 knots the rudder is turned through 30 degree. Find the initial angle of heel if the force Fr perpendicular to the plane of the rudder is given by:

Fr=577Av2 Sin  a N

Allow 20% for the race effect. (10)

Q7. (a) Describe how bulkheads are tested.

B. The following data are available for a twin-screw vessel:

V (Knots)
15
16
17
18
Epn (KW)
3000
3750
4700
5650
QPC
0.73
0.73
0.72
0.71
Calculate the service speed if the breaker power for each engine is 3500Kw. The transmission is 3% and the allowances for weather and appendages 30%.

Q8. (a) Explain what is meant by left and right handed propellers, and also explain the rotation of propellers in a twin-screw ship.

b) A ship 120m long displaces 8000 tonne, GML is 102m, TPC 17.5 and LCF 2m aft of midships. It arrives in port with draughts of 6.3m forward and 6.6m aft.

During the voyage the following changes in loading have taken place:

Fuel used          200 tonne         18m forward of midships

Water used        100 tonne         3m aft of midships

Stores used        10 tonne           9m aft of midships

Ballast added     300 tonne         24m forward of midships

Calculate the original draughts. (10)

Q9. A. Explain the effect of bilging a centreline compartment located away from amidships.

b) A ship of 4000 tonne displacement has a mass of 50 tonne on board, on the centre line of the tank top. A derrick, whose head is 18 m above the CG of the mass, is used to lift it. Find the shift in the ship's centre of gravity from its original position when the mass is

(i) lifted Just clear of the tank top

(ii) raised to the derrick head

(iii) placed on the deck 12 m above the tank top. (10)

Q10. A. With reference to dynamical stability, describe the effect of an increase in wind pressure when a vessel is at its maximum angle of roll to windward.

b) A box shaped vessel of length 100 metres and breadth 18 metres, floats in salt water on an even keel at 7.5 metres draft. KG = 4 metres. The ship has a continuous center line bulkhead which is watertight. Find the list if a compartment amidships, which is 15 metres long and is empty, is bilged on one side.