DieselShip's Online Content Library

Q1. With reference to corrosion processes:

a) Explain the mechanism of

i) Stress corrosion. (4)

ii) corrosion fatigue. (4)

b) State where the following types of corrosion may occur, and the materials commonly involved in each case.

i) Fretting corrosion. (4)

ii) Galvanic corrosion. (4)

Q2. a) Sketch the arrangement of rudder stock, bearings, glands and method of suspension of a pintleless rudder, labeling the components parts. (8)

b) State how the bearing wear down is measured and what prevents the rudder from jumping? (8)

Q3. Describe the construction of chain lockers and how cables are secured in the lockers? Explain how to secure anchors in preparation for a sea passage. (16)

Q4. a) Explain what is meant by 'panting' and 'pounding' and state which parts of the ship are affected? (8)

b) Describe in brief the loading conditions which give rise to hogging and sagging stresses. (8)

Q5. Write short notes on

a) Free surface effect (4)

b) Cavitation (4)

c) Reserve buoyancy (4)

d) Margin line (4)

Q6. A ballast tank is 15 m long, 12 m wide and 1.4 m deep and is filled with fresh water. Calculate the load on the top and short side, if:

a) the tank is just completely full

b) there is a head of 7m of water above the tank top. (16)

Q7. A box barge 25 m long and 4 m wide floats in fresh water at a draught of 1.2 m and has an empty mid length compartment 5 m long. The bottom of the barge is lined with teak (rd 0.805) 120 mm thick. After grounding all the teak is torn off and the centre compartment laid open to the sea. Calculate the final draught. (16)

Q8. The ½ ordinates of a waterplane 120 m long are as follows:

Section AP ½  1  1½  2  3  4  5  6  7  8  8½  9  9½  FP

½ord 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. (16)

Q9. A hopper barge of box form 50 m long and 10 m wide floats at a draught of 2 m in seawater when the hopper, which is 15 m long and 5 m wide, is loaded with mud having relative density twice that of the seawater, to the level of the waterline. Doors in the bottom of the hopper are now opened allowing the mud to be discharged. Calculate the new draught. (16)