CON & NA-FEB-2019

Q1. Describe the effect of the following on the ship’s stability; A. Ice formation on superstructures B. Effects of wind and waves C. Changes that takes place during the ships voyage D. Bilging of a compartment E. While water is being pumped out from the dry dock.

Q2. Describe the construction of a forepeak tank. How are the effects of panting and pounding taken care?

Q3. Describe the phenomenon of parametric rolling. what are the measures taken to prevent parametric rolling of ships.

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.

Q5. With reference to Ship stability: a. With the help of a neat sketch explain the relevant features of a G-Z curve. b. What are the effects of the below mentioned conditions on the G-Z curve:

i. Increased freeboard,

ii. Increased beam, and

iii. Increased GM

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 co- efficient.

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 water plane area co-efficient is 0.83 and the difference between the TPC in sea water and the TPC in fresh water is 0.7. Determine the length of the ship and the TPC in fresh water.

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. With the aid of sketches: a. Explain various lines plan.

b. The half -breadths of waterplane of a ship of 120m length ad 15m breadth are given below: Station 0 1 2 3 4 5 6 7 8 Half- breadth 1.6 2.8 5.5 6.4 7.3 6.2 4.2 2.0 0 Calculate i) Water plane area ii) TPC in salt water iii) Cw iv) LCF from Mid-ship.

Q9. With reference to inclining experiments; A. List the precautions necessary before an inclining experiment is carried out.

B. A box shaped vessel, 50 metres long × 10 metres wide, floats in salt water on an even keel at a draft of 4 metres. A centre line longitudinal watertight bulkhead extends from end to end and for the full depth of the vessel. A compartment amidships on the starboard side is 15 metres long and contains cargo with permeability 30%. Calculate the list if this compartment is bilged. KG = 3 metres.

Q10. With reference to subdivisional stability; 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 tonne of water ballast. Neglecting the free surface effect, calculate the angle which the ship will heel, when the ballast water is pumped out.