DieselShip's Online Content Library

Q6.a) Sketch and describe the midship section of a bulk carrier, labelling the structural members. (6)

b) A vessel 40 m long has a constant cross-section in the form of a trapezoid 10 m wide at the top, 6 m wide at the bottom and 5 m deep. It floats in sea water at a draught of 4 m. Calculate its displacement. (10)

Q8. The 1/2 ordinates of a waterplane 120 m long are as follows: (16)

Calculate: (a) Waterplane area(b) Distance of centroid from midships.

Q8. a) What are the routine maintenance carried out on lead acid batteries? (6)

b) When a 10 Ω resistor is connected across a battery, the current is measured to be 0.18 A. If similarly tested with a 25 Ω resistor, the current is measured to be 0.08A. Find the e.m.f. of the battery and its internal resistance. Neglect the resistance of the ammeter used to measure the current. (10)

Q6. The resistors 5Ω, 7Ω, and 8Ω are connected in series across a voltage source of 10 V. Find the voltage drop across each resistor and also the total power consumed by the circuit. (16)

Q9. (a) Explain what is meant by phase difference between voltage and current values. (6)
(b) An inductance coil has a resistance of 19.5Ω and when connected to a 220V, 50Hz supply, the current passing is 10A. Find the inductance of the coil. (10)

Q8. (a) Describe the effect of running an induction motor on reduced voltage.

(b) A motor takes a current of 60 amperes at 230 volts, the power input being 12 kW. Calculate the power component and the reactive component of the input current. (10)

Q8. (a) What is a 'mast riser' and what is the purpose of it? (6)

(b) A ship 96 m long is floating at 5m fwd draft and 6.4 m aft draft, MCTC 180 tm, TPC 16. COF is 2 m abaft of midships. Find the location where a weight of 50t should be placed so as to keep the aft draft constant. (10)

Q5. a) Describe an accurate method of comparing the capacities of two condensers. (6)

b) A resistor of 0.525 ohms is connected to the terminals of a battery consisting of 4 cells, each e.m.f. 1.46 V joined in parallel. The circuit current is found to be 0.8 A. Find the internal resistance of each cell. (10)

Q8. a) What is a Zener diode? (6)

b) Find the generated e.m.f./conductor of a 6-pole d.c. generator having a magnetic flux/pole of 64m Wb and a speed of 1000 rev/min. If there are 468 conductors, connected in six parallel circuits, calculate the total generated e.m.f. of the machine. Find also the total power developed by the armature when the current in each conductor is 50 A. (10)

Q5. A circuit has a resistance of 3Ω and an inductance of 0.01H. The voltage across its ends is 60V and the frequency is 50Hz. Calculate

a) The impedance (6)

b) The power factor (5)

c) The power absorbed. (5)

Q5. A) Explain three methods of overcurrent protection for electric circuit (6)

b) A circuit has a resistance of 3Ω inductance of 0.01H. The voltage across its end is 60V and the frequency is 50Hz. Calculate,

(i) the impedance (4)

(ii) the power factor (3)

(iii) the power absorbed. (3)

Q9. (a) What are the water pressure loads on the ship's hull. (6)

(b) The water plane area of a ship at 8.4 m draught is 1670 m². The area of successive water planes at 1.40 m intervals below this are 1600, 1540, 1420, 1270, 1080 and 690 m² respectively. Calculate the displacement in fresh water at 8.4 m draught and the draught at which the ship would lie in sea water with the same displacement. (10)