Page 438 - statbility for masters and mates

426 Ship Stability for Masters and Mates
GENERAL SHIP KNOWLEDGE
Attempt ALL questions
Marks for each question are shown in brackets
1. A combustible gas indicator (explosimeter) is used to check the atmo- sphere of a cargo oil tank.
(a) Describe how the instrument is used. (5)
(b) State the information given by the instrument. (5)
(c) State THREE circumstances where a zero reading may give a false
idea of the cargo tank atmosphere. (15)
2. (a)
(b) Explain why TPC changes with the draft of a conventional ship.(10)
(c) Explain how the TPC in fresh water may be found. (5)
De®ne TPC and explain its use. (5)
3. A ship has been laid up for four months. Before the ship re-enters service, a survey is necessary. The fore-peak tank which is empty, requires inspection.
State the safety precautions that should be taken. (25)
4. A ship has a load draft of 3.80 m in seawater.
The present mean draft in seawater is 3.30 m and KG is 3.65 m.
40 tonnes of bunkers are then loaded at Kg 0.50 m giving a free surface moment of 150 tonnes metres. The loading plan requires 100 tonnes of cargo to be loaded in the hold at Kg. 2.50 m and the remainder of the cargo to be loaded on deck at Kg 5.00 m.
Using the Worksheet Q.4, calulate EACH of the following:
(a) the weight of deck cargo; (10) (b) the load KG; (10) (c) the metacentric height when fully loaded. (10)
5. A ship is upright. A 10 tonne container is then lifted with the ship's own derrick from the centre-line of the lower hold and is re-stowed on the port side of the weather deck.
Explain, with suitable sketches, the movement of the ship's centre of gravity when the container:
(a) is ®rst lifted; (10) (b) is swung to the port side; (10) (c) is landed on the weather deck. (10)
6. Describe FIVE main hazards which can occur with the carriage of solid bulk cargoes. (20)