DieselShip's Online Content Library

Q1. Describe with the aid of sketches how each of the following contribute towards improving the propulsive efficiency of a ship: (16)

(a) Ducted propeller

(b) Costa bulb as fitted to rudder

(c) Grim wheel vane as fitted aft of the propeller

Q2. A virtual rise in the centre of gravity of a ship may be caused by (16)

(a) Filling a partially filled tank

(b) Using an onboard crane to lift a freely swinging heavy object

(c) Emptying a partially filled tank

(d) Transferring pipe from the setback area to the pipe rack Briefly Justify your Answer

Q2. a) Sketch a water-tight door and frame showing manner of attachment to bulkhead and the additional reinforcement carried by the bulkhead to compensate for the aperture. (6)

b) Explain how water-tightness of the door and frame mating surface is ensured with a hydrostatic pressure tending to force the faces apart. (5)

(c) Describe the means of remote closing operation of the door and state how many closing stations there are and their position. (5)

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)

Q6. (a) Explain in brief the term 'bulwark" and 'freeing port'. (6)

(b) A ballast tank is 15 m long, 12 m wide and 1.4m deep and is filled with fresh water. Calculate the load on the top and short side, if: (10)

(i) The tank is just completely full

(ii) There is a head of 7m of water above the tank top.

Q7. (a) What is Freeboard of a Ship? Why oil tankers have less freeboard? (6)

(b) 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 5m long. The bottom of the barge is lined with teak (rd 0.805) 120mm thick. After grounding all the teak is torn off and the centre compartment laid open to the sea. Calculate the final draught. (10)

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 vessel about to complete loading in a summer zone is expected to enter a winter zone after steaming from the loading port for 10 days. On passage, fuel consumption is expected to be 30 tonnes per day and water consumption 15 tonnes per day. The ship is at present floating in water of density 1.013 tonnes/m3 at a draft of 9.0m. (16)

Summer load draft: 9.475m FWA: 203mm TPC: 30 tonnes/cm Find

(a) The maximum permissible draft on completion of loading.

(b) The amount of cargo which the vessel can load. (Note: A vessel passing from a summer zone to a winter zone, or from a tropical zone to summer zone, must arrive at the zone boundary at the draft appropriate to that zone).