670 NIOUOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE

5. Define what is meant by the terms " centre of gravity " and "centre

of buoyancy" as applied to a ship.

6. A box-shaped vessel when light has a mean draught of 2 feet and

its loaded draught is 10 feet forward and 11 feet aft If the T.P.I
is 10, how much cargo can be loaded in the vessel ?

7. What faulty distribution of cargo would Droduce (a) hogging;

(&) sagging ; (c) collapsing stresses?

8. Sketch and describe how beams are connected to the frames.

9. Draw a figure of the load line marks of a steamship, naming the

several lines, and state to which edge a vessel is loaded.

Paper 5.
1
1. Is it advisable to use a swinging derrick when unloading a bag cargo?
Give reasons.
2. State fully bow you would dunnage and load a cargo of cement in
barrels. '
3. What precautions, if any, should be taken with deck winches in
cold weather1? Steam is escaping badly from the cylinders of
a winch, what is this due to and how is it remedied ?
4. What principal purposes do transverse watertight bulkheads fulfil 1
5. What is a stringer plate? Sketch and describe how it is fitted at an
upper deck.
6. The sea-cock of a double bottom is left open, the waterline is 10 feet
above the top of the tank, the area of which is 1500 square feefc.
What is the total upward pressure on the tank top?
7. Given the following data, construct a graph:—
Mean draught 2 ft. 3 ft. 5 ft. 7 ft.
T.P.I. 4-7 tons 10-7 tons 13*6 tons 15"5 tons,
If the vessel loads 40 tons of cargo at a mean draught of 4 feet,
what is the change of draught.
8. What is meant by " pounding " and how is it counteracted ?
9. Draw the following to scale:—Length of derrick 50 feet; from hee5
of derrick to span on naast 40 feet; angle between derrick and
mast 30°; weight suspended ixom the end of derrick, 3 tons.
From your figure find the approximate thrust on the heel of tha
derrick and the strain on the span.