CON & NA-APR-2021 (MUM)

Q1. A. Sketch a transverse section through the hold space of a container ship hull; 

B. Referring to the sketch in (A) describes how adequate structural strength is built into the hull.

Q2. The Hull of a vessel in way of the purifier room requires extensive welding repairs and as a 2nd Engineer officer you are required to supervise. a. Suggest a suitable type of welding process. b. State, With reasons, FOUR common welding defects. c. State what tests may be carried out for the hull repair before returning the vessel to service.

Q3. With reference to rudder carrier beings fitted to Merchant Ships: A. Sketch a bearing designed to transfer the full weight of the rudder to the ship's structure. B. Describe the consequence If the rudder carrier bearing surfaces become heavily scored. C. Describe the consequence and the action to be taken if the carrier shatters.

Q4. Describe a forced ventilation system for the machinery spaces and a natural ventilation system for a lower hold. Why hold ventilation is considered necessary?

Q5. Explain how the period of a 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.

Q6. A. Describe briefly the significance of the factor of sub-division;

B. A box-shaped vessel 65m X 12m X 8m has KG 4m and is floating in seawater upright on an even keel at 4m draft F and A. Calculate the moments of statically stability at i. 5 degrees and ii. 25 degrees’ heel.
 

Q7. A. Describe the effect of cavitation on the propeller blades.

B. A propeller 4.6m diameter has a pitch of 4.3m and boss diameter of 0.75. The real slip is 28% at 95 revs/min. Calculate the speed of advance, thrust and thrust power.
 

Q8. 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 2550kW. Calculate: (i) Indicated power; (ii) Effective power; (iii) Ship speed.

 

Q9. A ship of 9.900 tonnes displacement has KM 7.3m and KG 6.4m. She has yet to load two 50 tonne lifts in her own gear and the first lift is to be placed on deck on the inshore side (KG = 9m and centre of gravity = 6m, out from centre line). When the derrick plumbs the quay, its head is 15m above the keel and 12m out from the centre line. Calculate the maximum list during the operation.

 

Q10. A. Explain the use of KN curves. B. A ship of 8000-tonne displacement, 110m long, floats in sea water of 1.024t/m3 at draughts of 6m forward and 6.3 m aft. The TPC is 16, LCB 0.6 m aft of midships, LCF 3m aft of midships and MCT1cm 65-tonne m, the vessel now moves into the fresh water of 1.000t/m3. Calculate the distance a mass of 50 tonnes must be moved to bring the vessel to an even keel and determine the final draught.