DieselShip's Online Content Library

Q1.a) Describe the following and explain their function (8)

i) Hawse pipe

ii) Spurling pipe

iii) Cable stopper

iv) Bitter end

b) With the aid of a sketch of a ship bow show the arrangement of anchor cable from anchor to chain locker. (8)

Q2. In the absence of external forces, adding weight to one side of a floating vessel, will cause the vessel to (16)

(a) Heel until the angle of loll is reached.

(b) List until the centre of buoyancy is aligned vertically with the centre of gravity.

(c) Trim to the side opposite TCG until all moments are equal.

(d) Decrease draft at the centre of flotation.

Briefly justify your answer.

Q3. a) Draw a labelled sketch of midship section of a double hull oil tanker. (8)

b) What are Aframax, Suezmax, ULCC and VLCC tankers? (8)

Q4. a) What are the advantages of corrugated bulkheads? (6)

b) Sketch and describe a corrugated transverse watertight bulkhead (10)

Q5.a) What is free surface effect. (6)

b) Explain the methods used to reduce the free surface effect in ship construction and while operating the ship. (10)

Q6. (a) What is the significance of GM-GZ curve. (6)

(b) The pitch of a propeller is measured by means of a batten and cord. The horizontal ordinate is found to be 40 cm while the vertical ordinate 1.15 m at a distance of 2.6 m from the centre of the boss. Calculate the pitch of the propeller and the blade width at that point. (10)

Q7. (a) Explain why the draught of a ship decreases when it passes from fresh water to seawater and vice versa. (6)

(b) A lock gate which is 15m wide has salt water on one side to a depth of 8m and fresh water on the other side to a depth of 9m. Find the resultant thrust on the lock gate and state on which side of the gate it acts. (10)

Q8. (a) Describe the function of the stern frame. (6)

(b) The water plane area of a ship at 8.4 m draught is 1670 m2. The area of successive water planes at 1.40 m intervals below this are 1600,1540, 1420, 1270, 1080 and 690 m2 respectively. Calculate the displacement in fresh water at 8.4 m draught and the draught at which the ship would lie in sea water with the same displacement. (10)

Q9. a) Explain why an unstable ship is dangerous. (6)

(b) A vessel travelling at 17 knots turns with a radius of 450 m when the rudder is put hard over. The centre of gravity is 7 m above the keel, the transverse metacentre 7.45 m above the keel and the centre of buoyancy 4 m above the keel. If the centripetal force is assumed to act at the centre of buoyancy, calculate the angle of heel when turning. The rudder force may be ignored. (10)

Q1. For a ship the center of buoyancy and the metacenter are in the line of action of the buoyant force.

(a) Only when there is positive stability

(b) Only when there is negative stability

(c) Only when there is neutral stability

(d) At all times

Justify your answer.

Q2. Explain the meaning and purpose of EACH of the following terms:

(a) Duct keel (4)

(b) Margin line (4)

(c) Sheer (4)

(d) Round of Bilge (4)

Q4. With reference to hull protection against corrosion describe how EACH of the following operate:

a) Sacrificial anodes (8)

b) Impressed current system (8)

Q4. With reference to bilge keels:

(a) Describe how the design and method of attachment reduces the possibility of damage to the shell plate. (8)

(b) State what testing must be carried out. (4)

(c) Explain why the bilge keels do not extend the full length of the vessel. (4)

Q5. With reference to large bulk carriers:

(a) Sketch a cross section of a bulk carrier through the mid-ship. (8)

(b) Explain the design features that have evolved to minimise the possibility of failure. (8)

Q6. (a) Define angle of loll (6)

(b) A box barge 60 m long and 10m wide floats at an even keel draught of 4 m. It has a compartment amidships 12 m long. Calculate the new draught if this compartment is laid open to the sea when: (10)

(i) µ is 100%

(ii) µ is 85%

(iii) µ is 60%

Q7. (a) What do you understand by ‘coffin plate’?

(b) A ship displacing 10000 tonne and travelling at 16 knots has a fuel consumption of 41 tonne per day. Calculate the consumption per day if the displacement is increased to 13750 tonne and the speed is increased to 17 knots. Within this speed range, fuel consumption per day varies as (speed)^3/8 (10)

Q8. (a) Compare fixed pitch with controllable pitch propellers. (6)

(b) A ship of 12400 tonne displacement is 120 m long, 17.5 m beam and floats at a draught of 7.5 m. The propeller has a pitch ratio of 0.75 and, when turning at 100 rev/min, produces a ship speed of 12 knots with a real slip of 30%. Calculate the apparent slip, pitch and diameter of the propeller. The wake fraction w may be found from the expression. w = 0.5Cb - 0.05 (10)

Q9. (a) Describe water pressure loads on the ship's hull. (6)

(b) The 1/2 ordinates of a waterplane 120 m long are as follows: (10)

Section AP 1/2 1 1½ 2 3 4 5 6 7 8 8½ 9 9½ FP

½ ord 1.2 3.5 5.3 6.8 8.0 8.3 8.5 8.5 8.5 8.4 8.2 7.9 6.2 3.5 0 m

Calculate:

(a) Waterplane area

(b) Distance of centroid from midships.