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Q10. A. (i) What is direct-connected alternator?

(ii)  How is a direct-connected exciter arranged in an alternator?

B. Find the synchronous impedance and reactance of an alternator in which a given field current produces an armature current of 200 A on short circuit and a generated e.m.f. of 50V on open circuit. The armature resistance is 0.1 ohm. To what induced voltage must the alternator be excited if it is to deliver a load of 100A at a p.f of 0.8 lagging, with a terminal voltage of 200V.

Q8. A. What is slip? What are the factors on which the torque or an induction motor depends?  B) Calculate the pitch factors Kp for a wiping having 24 stator slots, 4 poles, when the coil span is 1 to 6

Q10. two shunt generators X and Y work in parallel. theri external characteristics may be assumed to be liner over their normal working range. The terminal voltage of X falls from 265V on no load to 230V. When delivering 350A to the bus bars, while the voltage falls from 270V on no load to 240V when delivering 400A to the bus bars, calculate the current which each machine delivers when they share a common load of 500A, what is the bus bar voltage under this condition and power delivered by each machine?

Q10. A ship of length 140m, Breadth of 18.5m, draught of 8.1m and a displacement of 17,025 tonnes in sea water, has a face pitch ratio of 0.673. Diameter of the Propeller is 4.8m. The results of the speed trial show that true slip may be regarded as constant over a range of 9 to 13 knots and is 30%, w = 0.5CB-0.05. If fuel used is 20t/day at 13 knots and fuel consumption/day varies as cube of speed of ship, Determine the fuel consumption, when propeller runs at 110 rpm.

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.

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Calculate EACH of the following:

(a) The equivalent base area value Ab;

(b) The longitudinal position of the center of buoyancy from midships;

(c) The vertical position of the center of buoyancy above the base.

Q1. Vessel has gone through very heavy weather. On arrival at safe anchorage, you are conducting your inspection to determine damages to hull.

A. List the areas you will inspect.      B. List your findings of any significance.

C. Write a report to company suggesting repairs if any.

Q2. The half-ordinates(m) of a waterplane, which are 6m apart, are given by: 11,16,24,84,39,42,47,52,40,23,26,46,13,23.

Calculate and compare the areas of waterplane as given by the 1,4,1 rule, the 1,3,3,1 rule and the trapezoidal rule

Q6. a) Describe how the distribution of mass within the ship affects the rolling period. (6)

b) The righting moments of a ship at angles of heel of 0, 15°, 30°, 45°, and 60° are 0, 1690, 5430, 9360 and 9140 kN-m respectively. Calculate the dynamical stability at 60°. (10)

Q7. A. Explain what is meant by ‘assigned summer free board’. B. A ship 120m long has draughts of 6.6m forward and 6.9 aft. The TPC is 20, MCTI cm 101 tonne m and the centre of flotation 3.5m aft of midships. Calculate the maximum position aft at which 240 tonne may be added so that the after draught does not exceed 7.2m

Q10. A. List the components of residuary resistance. B. The following data are available for a twin-screw vessel:

Calculate the service speed if the brake power for each engine is 3500Kw. The transmission is 3% and the allowances for weather and appendages 30%.

Q9. A) Define longitudinal centre of gravity (LCG) and longitudinal centre of buoyancy (LCB).(6) B) A vessel, when floating at a draught of 3.6 m has a displacement of 8172 tonne, KB 1.91 m and LCB 0.15 m aft of midships. From the following information, calculate the displacement, KB and position of the LCB for the vessel when floating at a draught of 1.2rn. (10)

Q9. A. Describe the procedure for speed, Power and fuel consumption trials. B. A propeller of 4m pitch has an efficiency of 67%.  When turning at 125 rev/min the real slip is 36% and the delivered power 2800Kw.Calculate the thrust of the propeller.