402 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
on top of it. Knots can be1 tied ID the spunyarn, or tallies tied on,
fco indicate which lot is beneath it and a corresponding note made in
the cargo book.
22. What precautions must be observed when taking in gunpowder?
A magazine must previously be constructed in a suitable place
in the 'tween decks, and, when receiving it on board, all fires must be
put out until it is stowed and secured. Any electric wiring passing
through the compartment must be disconnected. The flag B must be
hoisted
23. Where must dangerous liquids be stowed, such as aquafortis,
vitriol, etc.
In the most suitable place on deck, as in case of leakage it may be
necessary to jettison all or part of it. It should be well secured and
covered with tarpaulins or canvas.
24. What precautions must be observed at sea when carrying coal
cargoes?
To keep the surface well ventilated by taking ofi some of the hatches
when the weather permits, and keeping ventilators open. Also, the
temperature in different parts of the hold should be tested daily and
entered in the log; if it exceeds 77° Fahr. there is risk of the coal
being on fire.
25. How many tarpaulins would you put on your hatches?
Two good ones with an additional older one on top.
26. How are they secured?
By turning the edges inwards and jamming them hard up against
the hatch coamings by means of hatch bars and wooden wedges. Iron
cleats are fitted to the hatch coamings for this purpose.
27. What makes a hatch coaming watertight?
It has an angle iron riveted to it and to the deck all round the hatch.
This is made watertight by caulking at the time the ship is built.
28. What is the use of camber on the deck?
To give it additional strength and enable it to be quicJdy cleared
of water.
29. How would you parbuckle a cask out of a tier?
Take the bight of a rope and pass its two parts one under eacb