DieselShip's Online Content Library

Q1. (a) What is significance of the area under the curve of statical stability or the GZ curve? Explain using a neat diagram, how this curve is used to assess the stability of the ship against a heeling arm.

(b) In a grain carrier, how the shifting of grain affects the curve of statical stability. With a neat diagram explain the existing minimum criteria for stability of grain carrying ships. (8).

Q2. State how and why the following machinery items are effected when the maximum service speed of a Vessel is consistently maintained in heavy weather.

A. Intermediate shafting,

B. Propeller shafting,

C. Shafting coupling bolts,

D. Main thrust pads.

Q3: With reference to dry docking, define the responsibility of the second engineer;

A. Prior to docking;

B. Whilst the vessel is in dry dock;

C. Prior to flooding and leaving the dock.

Q4. (a) The stresses acting on a ship during its lifetime can be divided into two categories, with respect to still water stresses and dynamic stresses. State the different stresses in EACH category, explaining how EACH stress is caused.

(b). Explain how the structure is designed to combat longitudinal stresses.

Q5. Show by means of a sketch how transverse force is generated by turning a rudder. How is this force converted to turning moment? Can similar transverse force be generated by a transverse thruster? Where should this be located for maximum turning effect?

Q6. A ship 90 m long displaces 5200 tonne and floats at draughts of 4.95m forward and 5.35 m aft when in sea water of 1023 kg/m3. The water plane area is 1100m2, GML 95m, LCB 0.6m forward of midships and LCF 2.2m aft of midships. Calculate the new draughts when the vessel moves into fresh water of 1002 kg/m3

Q8. A. Define longitudinal centre of gravity (LCG) and longitudinal centre of buoyancy (LCB).

B. The immersed cross-sectional area of a ship 120m long, commencing from aft are 2,40,79,100,103,104,104,103,97, 58 and 0 m2 calculate :

(i) Displacement;

(ii) Longitudinal position of the centre of buoyancy.

Q8. A ship 160m long and 8700 tonne displacement floats at a waterline with

While floating at this waterline, the ship develops a list of 10° due to instability. Calculate the negative metacentric height when the vessel is upright in this condition

Q9. With respect to Inclining Experiments onboard vessels;

A. Sketch and Describe briefly the inclining experiment and explain how the results are used.

B. A forward deep tank 12 m long extends from a longitudinal bulkhead to the ship’s side. The widths of the tank surface measured from the longitudinal bulkhead at regular intervals are 10, 9, 7, 4 and 1 m. Calculate the second moment of area of the tank surface about a longitudinal axis passing through its centroid.

Q10. (a) What is meant by Quasi Propulsive Coefficient?

A ship of 15000 tonne displacement has mechanical efficiency of the machinery is 83%, shaft losses 6%, propeller efficiency 65% and QPC 0.71. At a particular speed the thrust power is 2550 KW. Calculate: (i) Indicated Power; (ii) Effective power.