PORT ECONOMICS

a vessel will move to another berth to receive outgoing
freight. This serves to relieve the congestion which
might ensue if a great quantity of imported goods and
cargo for exportation were congregated on a single quay,
and, in cases of extreme urgency, it further allows of the
vessel discharging its incoming freight at a rapid rate,
turning everything out pell-mell into the space available,
for subsequent sorting and dispatch.

If the vessel is due to proceed to another berth, which
may not only be for the above reason, but also because
she may be taking away cargo of an entirely different
and special character—such as coal—after arrangement
with the dock superintendent and dock master, the dock
pilot again comes on board with a staff of riggers and with
tugs in attendance. Riggers are a class of sailors working
only in port; they take the place of the discharged crew
pending the signing on of a fresh crew. The vessel is then
manceuvred into her new berth and the operation of
loading is begun.

CARGO CARRYING CAPACITY

The amount of cargo which a vessel may receive depends
very largely, though not altogether, on the Plimsoll mark
or Loadline disc, which indicates the maximum depth to
which she may be submerged. This is a White Circle,
12 in. in diameter, painted on the starboard side of the
vessel with a horizontal line 18 in. long through the centre.
The upper edge of the line indicates the loadline limit in
salt water during the summer months (April to October).
Other lines give limits for Fresh Water (F.W.) loading
(5 or 6 in. more than in salt water) ; for Indian Summer
(1.S.) ; Winter (W.) ; and Winter North Atlantic (W.N.A.)
conditions.

A vessel having been submerged to the appropriate line
is said to be Down—but she may not be Full. A heavy
cargo of pig iron, or ore, will bring her down to the loadline,
and leave a considerable proportion of her holds empty—

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