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Q10. A ship of 14000 tonne displacement is 125 m long and floats at draughts of 7.9 m forward and 8.5 m aft. The TPC is 19, GML 120 m and LCF 3 m forward of midships. It is required to bring the vessel to an even keel draught of 8.5m. Calculate the mass which should be added and the distance of the distance of the centre of the mass from midships. (16)

Q9. (a) With aid of a simple sketch, show the normal positions of centre of gravity of a stable ship relative to keel, centre of buoyancy and meta centre. (6)

(b) A ship has 300 t of cargo in the hold, 24 m forward of the midships. The displacement of the vessel is 6000 t and its centre of gravity is 1.2 m forward of midships. Find the new position of the centre of gravity if this cargo is moved to an after hold, 40 m from midships. (10)

Q8. A bilge holding tank of 5 m length, 3 m width and 1.8 m depth has water of density 1.020 t/m3 upto a sounding of 1.3 m and oil of density 0.86 t/m3 is floating on top of water upto an ullage of 0.3 m. Calculate the mass of water and oil in the tank (16)

Q8. a) Explain clearly the meaning of the term "reserve buoyancy". (6)

b) The centre of gravity of a ship of 5000 tonne displacement is 6 m above the keel and 1.5 m forward of midships. Calculate the new position of the centre of gravity if 500 tonne of cargo are placed in the t’ween decks 10 m above the keel and 36 m aft of midships. (10)

Q7. A moving-coil instrument has a resistance of 10 Ω and requires a current of 15 mA to give full- scale deflection. Calculate the resistance value of the resistor necessary to enable it to be used to measure

a) currents up 25A

b) voltages up to 500V. (16)

Q5. A 4-pole lap wound DC shunt generator has an open e.m.f of 250V when the flux per pole is 0.08 Wb and the speed is 10 rev/sec. The speed of the generator is reduced to 10 per cent and the flux per pole is increased by 5% when the generator supplies a load of 100A. Determine the terminal voltage, if the armature resistance is 0.06 ohms and the new total field circuit resistance is 200 ohm. (16)

Q9. (a) Explain why the TPC for a given draught will vary with the density of the water in which the ship floats. (6)

(b) A box shaped ship with 12m beam is floating upright at a draft of 6.7 m. Find the increase in draft if the vessel is now listed 18 degrees. (10)

Q9. (a) List the causes for impairment of stability of a vessel. (6)

(b) A box-shaped vessel floats upright on an even keel as shown in fresh water of density 1000 kg per cubic meter, and the center of buoyancy is 0.50 m above the keel. Find the height of the center of buoyancy above the keel when the vessel is floating in salt water of density 1025 kg per cubic meter. (10)

Q6. A 72 KVA transformer supplies a heating and lighting load of 12 KW at unity power factor and a motor load of 70 kVA at 0.766 (lagging) power factor; Calculate the minimum rating of the power-factor improvement capacitors which must be connected in the circuit the ensure that the transformer does not become overloaded.

Q9. A. List the factors that determine the starting torque of the three-phase induction motor. How does this torque generally compare with the value of the rated torque?

B. The low-voltage release of an a.c. motor-starter consists of a solenoid into which an iron plunger is drawn against a spring. The resistance of the solenoid is 35 ohm. When connected to a 220 V, 50 Hz, a.c. supply the current taken is at first 2A, and when the plunger is drawn into the “full-in” position the current falls to 0.7 A. Calculate the inductance of the solenoid for both positions of the plunger, and the maximum value of flux-linkages in weber-turns for the “full-in” position of the plunger.

Q4. A) Calculate the Line and Phase current at full load of a 50 kW, 440 Volt 3 phase deltas connected motor having full load efficiency 90% and power factor O.8 lagging. B) Calculate the starting current if motor is started by star/delta starter and Auto transformer starter which has transformer tapping 65 %

Q9. A. Show how the power that is transferred across the air gap of the three-phase induction motor is represented. Explain the terms. What portion of this is useful power? B. The primary and secondary windings of a 500 Kva transformer have resistance of 0.42 and 0.0019 respectively. The primary and secondary voltages are 11 000 V and 415 V respectively and the core loss is 2.9 Kw, assuming the power factor of the load to be 0.8. Calculate the efficiency on (i) Full load; (ii) Half load;