DieselShip's Online Content Library

Q1. Draw and describe the construction of a forepeak tank. Explain how are the effects of panting and pounding taken care with help of neat sketches?

Q2. A. Describe the double bottom and framing arrangement used in the machinery space to cope up with the concentrated loads and vibration, together with shaft and thrust block support.

B. Give reasons for the choice of thrust block position.

Q3. With respect to propellers:

(a) With simple sketches explain how to measure the pitch of propeller.

(b) How does cavitations take place? How can this effect be reduced?

(c) Compare the advantages and disadvantages between a built and a solid propeller.

Q1. With reference to International Load Line Statutory Certification,

A. State the reasons for the freeboard requirements;

B. (i) Explain the term “conditions of assignments”;

(ii) List the items that may be examined during a Load line survey after a vessel’s major repairs in the dry-dock.

Q5. Write short notes on resistance encountered by a sailing ship in water. What structural changes are in place to minimize them

Q7: An oil tanker 160m long and 22m beam floats at a draught of 9m in seawater. Cw is 0.865. The midships section is in the form of a rectangle with 1.2m radius at the bilges. A midships tank 10.5m long has twin longitudinal bulkheads and contains oil of 1.4 m3/t to a depth of 11.5m. The tank is holed to the sea for the whole of its transverse section.  Find the new draught.

Q9. With respect to Ship Propulsion:

a. Explain the various efficiencies associated with propeller and shafting arrangement.

b. When a propeller of 4.8 m pitch turns at 110 rpm, the apparent slip is found to be —S % and the real slip is 1.5 S %. If the wake speed is 25 % of the ship speed, calculate the ship speed, apparent slip and the real slip.

Q10. a) Describe the various resistances acting against the motion of the ship?

The following data are available from the hydrostatic curves of a vessel.

Calculate the TPC at a draught of 5.05m.

Q9. (a) Explain the concept of dynamical stability.

(b) A ship of 5000 tonne displacement has three rectangular double bottom tanks A: 12m long and 16m wide; Tank B: 14m long and 15m wide; C 14m long and 16m wide.

calculate the free surface effect for any one tank and state in which order the tanks should be filled when making use of them for stability correction.

Q10. (a) Explain what is meant by left and right handed propellers, and also explain the rotation of propellers in a twin-screw ship.

(b) A propeller 6m diameter has a pitch ratio of 0.9, BAR 0.48 and, when turning at 110 rev/min, has a real slip of 25% and wake faction 0.30. If the propeller delivers a thrust of 300 KN and the propeller efficiency is 0.65. Calculate:

i. Blade area;

ii Ship speed;

iii. Thrust power;

iv Shaft power

v. Torque.