DieselShip's Online Content Library

Q1: Define five of the following, stating how they affect the ship structure and what component parts of the ship structure help to resist the effect of - A. Raking; B. Water pressure effect; C. Panting; D. Pounding; (e)Local weights;(f) Vibration from engine and propellers.

Q9. A. Describe the general precautions to be taken against capsizing. State the recommended criteria for passenger and cargo ships.  B. The ½ ordinates of a water plane at 15m intervals, commencing from aft, ar. 1, 7, 10.5, 11, 11, 10.5, 8, 4 and 0m. Calculate: i. TPC; ii. Distance of the centre of flotation from midships; iii. C. Second moment of area of the water plane about a transverse axis through the centre of flotation.

Q3. Describe the effect on GM of rolling and how bilge keels, anti-rolling tanks and stabilizer fins reduce the amplitude of rolling.

Q7. With respect to trim and stability, describe the following - A. Effects on centre of gravity of slack tanks; B. Effect on stability of ice formation on superstructure; C. Effects of wind and waves on ship’s stability; D. Effect of water absorption by deck cargo and retention of water on deck.

Q4. With reference to the prevention of hull corrosion discusses:

A. Surface preparation and painting of new ship plates.

B. Design of the ships structure and its maintenance. C. Catholic protection by sacrificial anodes, of the internal and external areas of the ship.

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

B. A ship of 6000 tonne displacement has a wetted surface area of 2500 m2 and a speed of 15 knots.

(i) Calculate the corresponding speed and wetted surface area of as similar ship of 2000 tonne displacement.

(ii) 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 box-shaped vessel is 20 m long and 10 m wide.  The weight of the vessel is uniformly distributed throughout the length and the draught is 2.5 m.  The vessel contains ten evenly spaced double bottom tanks, each having a depth of 1m. Draw the shear force diagrams:

With No.1 and No.10 tanks filled; With No.3 and No.8 tanks filled; With No.5 and No.6 tanks filled.

Which ballast condition is to be preferred from the point of view of strength?

Q7. A. what is the effect on fuel consumption per unit time, if the ship’s speed is outside its operation range? B. The frictional resistance of a ship in fresh water at 3m/s is 11N/m2.  The ship has a wetted surface area of 2500m2 and the frictional resistance is 72% of the total resistance and varies as speed 1.92.  If the effective power is 1100Kw, calculate the speed of the ship.

Q9. A. Describe the procedure for speed, Power and fuel consumption trials. B. A propeller of 4m pitch has an efficiency of 67%.  When turning at 125 rev/min the real slip is 36% and the delivered power 2800Kw.Calculate the thrust of the propeller.

Q10. A. Explain the considerations which govern the size and shape of a rudder. B. A ship of 12000 tonne displacement has a rudder 15m2 in area, whose centre is 5m below the waterline.  The metacentric height of the ship is 0.3m and the centre of buoyancy is 3.3m below the waterline.  When travelling at 20 knots the rudder is turned through 30 .  Find the initial angle of heel if the force Fn perpendicular to the plane of the rudder is given by: Fa=577 Av2 sin  N, Allow 20% for the race effect.