CON & NA-OCT-2020

Q1. A. Describe the preparation necessary before the application (in day dock) of sophisticated or approved long life coating to the underwater surface of the hull; B. State the significance of the roughness profile. C. List the different sophisticated costing which are available.

Q2. A. Describe the double bottom and framing arrangement used in the machinery space to cope up with the concentrated loads and vibration, together with shaft and thrust block support. B. Give reasons for the choice of thrust block position.

Q3. Explain how the period of roll varies with –A. The amplitude of roll; B. The radius of gyration; C. The initial metacentric height; D. The location of masses in the ship.

Q4. 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.

Q5. 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? 

Q6. What is Prismatic Co-efficient (CP).a. Derive the formula CP =Cb/Cm, where Cb = Co-efficient of fineness and Cm = midship section area coefficient.

b. The length of a ship is 18 times the draught. while the breadth is 2.1 times the draught. At the load water plane, the waterplane area co-efficient is 0.83 and the difference between the TPC in seawater and the TPC in freshwater is 0.7. Determine the length of the ship and the TPC in freshwater.
 

Q7. With respect to Ship Propulsion: a. Explain the various efficiencies associated with propeller and shafting arrangement.

b. When a propeller of 4.8 m pitch turns at 110 rpm, the apparent slip is found to be —S % and the real slip is 1.5 S. If the wake speed is 25 % of the ship speed, calculate the ship speed, apparent slip and the real slip.
 

Q8. 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. 

Q9. (a) Explain the concept of dynamical stability. (b) A ship of 5000-tonne displacement has three rectangular double bottom tanks A: 12m long and 16m wide; Tank B: 14m long and 15m wide; C 14m long and 16m wide. calculate the free surface effect for anyone tank and state in which order the tanks should be filled when making use of them for stability correction.

Q10. 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 seawater on the only side - (i) to the top edge; (ii) with 4 m head to the top edge.