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Q7. A) Why is an inclining experiment carried out? Write short account of the method adopted.

b) An inclining experiment was carried out on a ship of 8000 tonne displacement. The inclining ballast was moved transversely through 12 m and the deflections of a pendulum 5.5m long, measured from the centreline, were as follows

3 tonne port to starboard 64 mm S

3 Tonne 116 mm S

Ballast restored 3 mm S

3 Tonne starboard to port 54 mm P

3 tonne starboard to port 113 mm P

Calculate the metacentric height of the vessel. (10)

Q8. A. Explain the purpose of non-watertight longitudinal subdivision of tanks. (6)

B. A ship 160m long and 8700 tonne displacement floats at a waterline with ½ ordinates of 0, 2.4, 5.0, 7.3, 7.9, 8.0, 8.0, 7.7, 5.5, 2.8, 0m respectively. While floating at this waterline, the ship develops a list of 10° due to instability. Calculate the negative metacentric height when the vessel is upright in this condition. (10)

Q7. a) Describe briefly the significance of the factor of subdivision. (6)

b) A ship 120m long has a light displacement of 4000 tonne and LCG in this condition 2.5m aft of midships.  (10)

The following items are then added:

Cargo 10000 tonne      LCG 3.0 m  forward of midships

Fuel 1500 tonne        LCG 2.0 m  aft of midships

Water         400 tonne  LCG 8.0 m  aft of midships

Stores        100 tonne LCG 10.0m forward of midships

Using the following hydrostatic data, calculate the final draughts:

Q10. A box-shaped vessel is 20 m long and 10 m wide.  The weight of the vessel is uniformly distributed throughout the length and the draught is 2.5 m.  The vessel contains ten evenly spaced double bottom tanks, each having a depth of 1m. Draw the shear force diagrams:

With No.1 and No.10 tanks filled; With No.3 and No.8 tanks filled; With No.5 and No.6 tanks filled.

Which ballast condition is to be preferred from the point of view of strength?

Q7. (a) Describe how bulkheads are tested.

B. The following data are available for a twin-screw vessel:

V (Knots)
15
16
17
18
Epn (KW)
3000
3750
4700
5650
QPC
0.73
0.73
0.72
0.71
Calculate the service speed if the breaker power for each engine is 3500Kw. The transmission is 3% and the allowances for weather and appendages 30%.

Q6. a) Derive the expression for current and voltage relations between line and phase values in the star and delta cases. Draw vector diagram. (6)

b) A balanced delta connected load is connected to a 415V, 50 Hz Supply. If the per phase impedance of the load is (8+j12) ohm, calculate (i) the phase current of the load. (ii) line current (iii) power consumed by each phase. (10)

Q6. a) Define centre of buoyancy and show with the aid of sketches how a vessel which is Stable will return to the upright after being heeled by an external force (6)

b) 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 2550 kW. (10)

Calculate:

(i) Indicated power

(ii) Effective power

(iii) Ship speed.

Q7. A ship consumes 360 t of fuel, stores and water when moving from sea water of 1.025 t/m3 into fresh water of 1.000 t/m3 and on arrival it is found that the draught has remained constant.

Calculate the displacement in sea water. (16)

Q7. a) Explain with the aid of a simple sketch ullage and sounding of a tank. (6)

b) A deep tank 10 m wide and 10 m deep has a rectangular manhole of 1.2 m X 0.6 m at the forward end. The longer sides of the manhole are horizontal and its lower edge is 0.7 m from the bottom of the tank. Find the thrust experienced by the manhole cover when the tank has oil of RD 0.8 to an ullage of 1 m. (10)

Q7. a) What is Kirchoff’s current Law. (6)

b) Calculate the value of I2 in the circuit, when I1= 3A. (10)

Q8. Find the p.d between A-B and B-C shown in the figure below. (16)

Q8. A 24 V emergency battery is to be charged from the 110 V ship’s mains when the e.m.f. per cell has fallen to a minimum value of 1.8 V. The battery consists of 12 cells in series, has a capacity of 100 Ahr at a 10 hr rate and the internal resistance is 0.03 ohm/cell. If charging continues until the voltage per cell rises to 2.2 V, find the value of the variable resistor needed to control the charging. The charging current can be assumed to be equal to the maximum allowable discharge current. (16)