DieselShip's Online Content Library

Q1. With reference to Statutory Certification:

a) State the reason for the freeboard requirements. (8)

b) (i) Explain the term conditions of assignments. (4)

(ii) List the items that may be examined during a related survey. (4)

Q2. a) Define the angle of loll with sketches and explain the conditions that lead to its occurrence on a vessel. (8)

b) Discuss the risk associated with an angle of loll and the corrective actions that can be taken to resolve the ship to an upright and stable condition. (8)

Q3. Explain the purpose and design of a bulbous bow in ship construction. How does the bulbous bow help in reducing friction and wave resistance? Discuss the impact of a bulbous bow on fuel efficiency, vessel stability, and overall hydrodynamic performance. (16)

Q4. Define ship’s total resistance. How this total resistance divided into various components? Write short notes on these components of resistance. (16)

Q5. If a ship is seriously damaged under water in way of a large fuel oil side bunker tank what is the immediate effect and what may ultimately happen? What features in the ship would enhance safety? (16)

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

B. A propeller has a pitch ratio of 0.95. When turning at 120 rev/min the real slip is 30%, the wake fraction 0.28 and the ship speed 16 knots. The thrust is found to be 400 KN, the torque 270 KN-m and the QPC 0.67. Calculate:

i. The propeller diameter;

ii. The shaft power;

iii the propeller efficiency;

iv. The thrust deduction factor.

Q7.A. Explain how to distinguish between list and loll and describe how to return the ship to the upright in each case.

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)

Q8. A. Why is it important in a tender ship to keep the double bottom tanks pressed up?

B. The fuel consumption of a ship at 17 knots is 47 tonne/day. The speed is reduced and the consumption is reduced to 22 tonne/day. At the lower speed, however, the consumption per unit power is 13.2% greater than at 17 knots. Find the reduced speed and the percentage saving on a voyage of 3000 nautical miles.

Q9. A. Describe how the force on the ship’s bottom and the GM vary when grounding takes place.

Q7. A box barge 45 m long and 15 m wide floats at a level keel draught of 2 m in sea water, the load being uniformly distributed over the full length. Two masses, each of 30 tonne, are loaded at 10 m from each end and 50 tonne is evenly distributed between them. Sketch the shear force diagram and give the maximum shear force.

Q10. (A) Explain the concept of dynamical stability.

B. A ship of 14000 tonne displacement is 125 m long and floats at draughts of 7.9 m forward and 8.5 m aft. The TPC is 19, GML 120 m and LCF 3 m forward of midships. It is required to bring the vessel to an even keel draught of 8.5m. Calculate the mass which should be added and the distance of the distance of the centre of the mass from midships.