DieselShip's Online Content Library

Q3. Give a reasoned opinion as to the validity of the following assertions concerning ship structure:

A. Crack propagation in propeller shaft ‘A’ brackets or spectacles frames is indicative of inadequate scantlings and strength;

B. The adequate provision of freeing ports is as critical to seaworthiness as watertight integrity.

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.

Q3. A. With reference to fatigue of hull structures explain the influence of stress level and cyclical frequency on expected operating life. B. Explain the influence of material defects on the safe operating life of forged components of stern fittings.

Q3. With regard to ship construction details for transverse watertight bulkheads: -

A. State the purpose of this type of bulkhead;

B. State how the bulkheads are tested for water tightness;

C. If it is necessary to penetrate the bulkhead, precaution must be taken to ensure that the watertight integrity and the strength of the bulkhead is maintained. In view of above, describe, using simple sketches, how the following pass through bulkheads.

i. Main transmission shaft;                ii. Electrical cables;

iii. Fuel oil transfer pipes;                iv. Air and sounding pipes.

Q5. The value of maximum righting arm is dependent upon the position of the center of buoyancy and the --- A. Longitudinal center of gravity; B. Transverse center of gravity; C. option Down flooding angle; D. Vertical location of the center of gravity. Deduce the relation of the you have selected with reference to the value of the maximum righting arm

Q6. A propeller has a pitch of 4.57m. At 100rev/min the real slip is 20 percent and wake speed is I knot.  Calculate the apparent slip percentage

Q7. A. Explain how increase of draught and of displacement influence rolling. (6)

B. A pontoon has a constant cross-section as shown in Fig. Given below the metacentre height is 2.5m. Find the height of the centre of gravity above the keel. (10)

Q8. A box barge of 60m long and 10m wide floats at a level keel draught of 3m. Its centre of gravity is 2.5m above the keel. Determine the end draughts if an empty, fore end compartment 9m long is laid open to the sea.

Q9. A ship of 6000 tonne displacement has a wetted surface area of 2500 m2 and a speed of 15 knots.  Calculate the corresponding speed and wetted surface area of as similar ship of 2000 tonne displacement. (i) If the ship resistance is of the form R=0.45 S V1.83 N; find the resistance of the 6000 tonne Ship.

Q10. A vessel of 12000 tonne displacement has a length along the load water line of 140m. The waterline lengths at 1m intervals of draught below this are 139, 138, 136.5, 134.5, 132 and 129m respectively. If the center of lateral resistance is at the centroid of this immersed area, calculate the angle to which he ships will heel due to centrifugal force when the vessel turns in a circle of 400m diameter when travelling at 16 knots with KG 5m and GM 0.4m