394

NICUOLLS'S  SEAMANSHIP   AND  NAUTICAL  KNOWLEDGE

of space is left in the holds when the ship is down to her load line
weight is unavoidably concentrated over a small area of the
thus causing excessive strains locally. (See Fig. 9, page 430 )
ships are, therefore, specially strengthened and designed for this
A transverse section of a special ore ship is shown in the illusti
Ores are loaded and discharged as in the case of coal, according
custom of the port
Grain.—The principal grain ports are Montreal, New York,
adelphia, San Francisco, Vancouver and ports in the Biver Plate
tralia and New Zealand. Rice is also classed as grain and is loac
bags at ports in the Far East, the chief being Calcutta, Rar
Bassein, Saigon and Bangkok.
TRUNK
Fig. 3.—Section of a Grain Carrier.
„ Grain when carried in bulk is very liable to shift, the angle of j
of a pile of grain being about 25 degrees, so that the rolling of a s
sea is capable of setting it in motion. Certain statutory regul
must be complied with, under heavy penalties for evasion, by t
in the North American, Mediterranean and Black Sea gram t
the rules being contained in a "Memorandum on Grain Cargoes"
by the Board of Trade.
Special types of ships have been built for the carriage of bulk
called trunk ships. Grain is pumped into the ship through a
canvas hose until the lower hold and the trunkway are comj
filled. The grain settles down from the efEect of tie ship's mot
sea, but the grain in the narrow trunkway acts as a feeder and
the hold quite full. Grain seeks into every hole and corner, so the
si^ce must be made graintight by caulking the open seams betwe<
, planks of the ceiling or by nailing thin narrow strips of wood ov
seams. When a ship, not specially built for the purpose, is requi