CON & NA-APR-2021

Q1. Draw and Describe the construction of a forepeak tank. Explain How are the effects of panting and pounding are taken care of with help of neat sketches? 

Q2. (a) Draw the midships section of an oil tanker with a Double Hull & name each part.(b) What is Bow Flare? Why is it so important in Bulk Carriers?

Q3. A. Explain what is meant by the permissible length of compartments in passenger ships; B. Describe how the position of bulkheads is determined. C. Describe briefly the significance of the factor of subdivision.

Q4. A. Define the purpose of cofferdams, B. State where cofferdams are most likely to be found on:(i) Dry cargo ships; (ii) Oil tankers.

C. (i) State what information is available about the danger of entering void spaces. (ii) Identify, with reasons, the precaution to be observed before and during entry to cofferdams.

Q5. A. Explain in detail, how an underwater survey is carried out;

B. State the requirements to be fulfilled before an underwater survey is acceptable to the surveying authority;

C. Construct a list of the items in order of importance that the underwater survey authority should include.

Q6. A. Define longitudinal centre of gravity (LCG) and longitudinal centre of buoyancy (LCB).

B. A ship 120m long floats has draughts of 5.50m forward and 5.80 forward and 5.80m aft; MCTI cm 80-tonne m, TPC 13, LCF 2.5m forward of midships. Calculate the new draughts which a mass of 110 tonne is added 24m aft of midships.
 

Q7. A. Describe how the force on the ship’s bottom and the GM vary when grounding takes place.

B. A ship of 8,000 tonnes displacement takes the ground on a sandbank on a falling tide at an even keel draft of 5.2 metres. KG 4.0 metres. The predicted depth of water over the sandbank at the following low water is 3.2 metres. Calculate the GM at this time assuming that the KM will then be 5.0 metres and that mean TPC is 15 tonne.
 

Q8. A ship 100 m long floats at a draught of 6 m and in this condition the immersed cross-sectional areas and water plane areas are as given below. The equivalent base area (Ab) is required because of the fineness of the bottom shell.

station AP 1 2 3 4 5 FP
X- area m2 12 30 65 80 70 50 0
Draft m 0 0.6 1.2 2.4 3.6 4.8 6.0
WP area m2 Ab 560 720 880 940 1000 1030
Calculate EACH of the following: (a) The equivalent base area value Ab(b) The longitudinal position of the centre of buoyancy from midships (c) The vertical position of the centre of buoyancy above the base.
 

Q9. With reference to fixed pitch propellers: a. Explain Propeller Slip and Propeller Thrust.

b. The shaft power of a ship is 3000 KW, the ship’s speed V is 13.2 knots. Propeller rps is 1.27. Propeller pitch is 5.5m and the speed of advance is 11 Knots. Find i. Real Slip ii. Wake fraction iii. Propeller thrust, when its efficiency, η = 70%.
 

Q10. A. What is meant by the Admiralty Coefficient and the Fuel Coefficient?

B. A ship of 14900-tonne displacement has a shaft power of 4460 kW at 14.55 knots. The shaft power is reduced to 4120 kW and the fuel consumption at the same displacement is 541 kg/h. Calculate the fuel coefficient for the ship.