CON & NA-JUL-2021 (1)

Q1. 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.

Q2. As a Second Engineer, you are required to supervise the vessel’s rudder which requires extensive welding repairs A. Suggest a suitable type of welding process; B. State with reasons FOUR common welding defects C. State what tests may be carried out before returning the rudder to service.

Q3. (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?

Q4. Describe the arrangement of a tank top and double bottom in the machinery space making particular reference to the structure and scantlings below the main engine. Show the method adopted in the arrangement of D.B. tanks to avoid contamination of fresh water, fuel oil and lube oil stored in D.B. tanks.

Q5. With reference to fatigue of engineering components:

A. Explain the influence of stress level and cyclical frequency on expected operating life;

B. Explain the influence of material defects on the safe operating life of an engineering component;

C. State the factors which influence the possibility of fatigue cracking of a bedplate transverse girder and explain how the risk of such cracking can be minimized.

Q6. 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.
 

Q7. A. Describe how water tightness is maintained where bulkheads are pierced by longitudinal beams or pipes. B. A triangular bulkhead is 7 m wide at the top and has a vertical depth of 8 m. Calculate the load on the bulkhead and the position of the centre of pressure if the bulkhead if flooded with sea water on the only side - (i) to the top edge; (ii) with 4 m head to the top edge.

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. The following data are available from the hydrostatic curves of a vessel. 

Draught (m)	KB(m)	KM(m)	I(m4 )
4.9	2.49	10.73	65.25
5.2	2.61	10.79	68.86

Calculate the TPC at a draught of 5.05m. 

Q10. A. Describe briefly the significance of the factor of subdivision..

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 centreline, contains 100 tonnes of water ballast. Neglecting the free surface effect, calculate the angle at which the ship will heel when the ballast water is pumped out.