DieselShip's Online Content Library

Q1. (a) List out the merits and demerits of longitudinal framing system. Explain which demerits of longitudinal framing system are mitigated by use of mixed framing system without affecting the merits?

(b) List and explain with a sketch the type of loads and failure mechanism that would be of concerns for the longitudinal strength of the hull girder of a bulk carrier

Q2. a) Explain the concept of metacentric height (GM) and its significance in ship stability. (4)

b) Differentiate between initial stability and overall stability. How are they assessed during ship design? (4)

c) Discuss the effect of free surface in tanks on the stability of a ship. How can this effect be minimized? (4)

d) Explain the criteria for determining a ship’s intact stability according to the International Maritime Organization (IMO) regulations. (4)

Q4. With the help of sketches explain the different types of strakes used in ship construction. What material is generally used for Hull plating and What are the tests carried out on Hull steel plating for certification as per class rules.

Q4. Discuss the different components of a ship’s total resistance as it moves through water. Explain how each component contributes to the overall resistance, and describe the methods used to reduce these resistances in modern ship design. (16)

Q1. Describe with the aid of diagrammatic sketches the following systems used for transporting liquefied gas in bulk:

a) Free-standing prismatic tanks

b) Membrane tanks.

c) Free-standing spherical tanks.

Q6. a) Define centre of buoyancy and show with the aid of sketches how a vessel which is Stable will return to the upright after being heeled by an external force (6)

b) A ship of 15000 tonne displacement has an Admiralty Coefficient, based on shaft power, of 420. The 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. (10)

Calculate:

(i) Indicated power

(ii) Effective power

(iii) Ship speed.

Q7. A. Describe stability requirement for dry-docking.

B. A ship of 8000 tonne displacement floats upright in seawater. KG = 7.6m and GM = 0.5m. A tank, KG is 0.6m above the keel and 3.5m from the centre line, contains 100 tonne of water ballast. Neglecting the free surface effect, calculate the angle which the ship will heel, when the ballast water is pumped out.

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.

Q9. a) Explain the term Angle of loll and state the dangers it poses to a vessel. What action to be taken to correct angle of loll. (6)

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. (10)

Q10. a) Explain the concept of dynamical stability. (6)

b) A ship of length 140m, Breadth of 18.5m, draught of 8.1m and a displacement of 17,025 tonnes in sea water, has a face pitch ratio of 0.673. The diameter of the Propeller is 4.8m. The results of the speed trial show that true slip may be regarded as constant over a range of 9 to 13 knots and is 30%, w = 0.5CB-0.05. If fuel used is 20t/day at 13 knots and fuel consumption/day varies as cube of speed of ship, determine the fuel consumption, when propeller runs at 110 rpm. (10)