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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.

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. Describe with the aid of a sketch, how the tanks are located and supported. i) Longitudinally; ii) Transversely

Q4. Describe a forced ventilation system for the machinery spaces and a natural ventilation system for a lower hold. Why hold ventilation is considered necessary?

Q7. With respect to trim and stability, describe the following - A. Effects on centre of gravity of slack tanks; B. Effect on stability of ice formation on superstructure; C. Effects of wind and waves on ship’s stability; D. Effect of water absorption by deck cargo and retention of water on deck.

Q4. With reference to the prevention of hull corrosion discusses:

A. Surface preparation and painting of new ship plates.

B. Design of the ships structure and its maintenance. C. Catholic protection by sacrificial anodes, of the internal and external areas of the ship.

Q6. a) Describe how the distribution of mass within the ship affects the rolling period. (6)

b) The righting moments of a ship at angles of heel of 0, 15°, 30°, 45°, and 60° are 0, 1690, 5430, 9360 and 9140 kN-m respectively. Calculate the dynamical stability at 60°. (10)

Q7. a) Describe briefly the significance of the factor of subdivision. (6)

b) A ship 120m long has a light displacement of 4000 tonne and LCG in this condition 2.5m aft of midships.  (10)

The following items are then added:

Cargo    10000 tonne      LCG 3.0 m          forward of midships

Fuel      1500 tonne        LCG 2.0 m          aft of midships

Water    400 tonne          LCG 8.0 m          aft of midships

Stores   100 tonne          LCG 10.0m         forward of midships

Using the following hydrostatic data, calculate the final draughts:

Q8. A. Explain the effect of trim on tank soundings. B.A ship of 6600 tonne displacement has KG 3.6m and KM 4.3m. A mass of 50 tonne is now lifted from the quay by one of the ship’s derricks whose head is 18m above the keel. The ship heels to a maximum of 9.5° while the mass is being transferred. Calculate the outreach of the derrick from the ship’s centreline.

Q9. A. Explain the effect on GM during the filing of a double – bottom tank, B. A ship of 8,000 tonnes displacement has KM 7.5m, and KG 7.0m.  A double bottom tank is 12 meters long 15 meters wide and 1 meter deep.  The tank is divided longitudinally at the centre line and both sides are full or small water. Calculate the list if one side is pumped on until it is half empty.

Q8. A ship of 9,900 tonnes displacement has KM=7.3 m and KG=6.4 m she has yet to load two 50 tonne lifts with her own gear and the first lift is to be placed on deck on the inshore side (KG 9 m and center of gravity 6m out from the center line). When the derrick plumbs the quay its head is 15m above the keel an 12m out from the center line.

Calculate the maximum list during operation.