CARGO PLANS 421
as loaded so that the owners, stevedores and consignees may see at a
glance where the cargo is stowed. Horizontal lines indicate cargo
for a first port of call, diagonal lines for a second port and vertical
lines for a third port. A distinctive colouring of the cargo for each
port might have been used, which would probably have been more
attractive but not so easily reproduced in a book.
Consideration has also to be given to the question of the ship's
stability when distributing the weight of cargo in the ship, but this
subject is dealt with in Chapter XVIII.
The measurement cargo capacity of a ship is known and is given
in her capacity plans, and the deadweight tons to put her down to the
load line marks is definitely fixed by statute. These two tonnage
values, measurement and weight, automatically adjust themselves
when a homogeneous cargo is loaded, for, obviously, if the ship is full
no more goods can be stowed on board even if she is not down to her
statutory load marks, and, conversely, if she is down to her load line
marks, even if her holds are not full, no more weight can be put on board
under pain of severe penalty for overloading
But when a cargo consisting of goods of different densities is to be
carried it may be desired to have the holds quite full and at the same
time have the ship down to her statutory load line. The determination
of the proportion of quantities calls for the solution of a simultaneous
equation which may be best illustrated by a worked example.
Example —A vessel of 9300 tons deadweight, loading in Calcutta,
has on board 1200 tons of coal, stores and water. Her hold capacities
in cubic feet are No. 1, 90270; No. 2, 108860; No, 3, 20750; No. 4,
102620; No. 5, 89370. Her cargo is to be 500 tons tea stowing at 110
cubic feet per ton, the remainder to be manganese ore in bulk at 18
cubic feet and gunny bales at 60 cubic feet per ton. Required the
quantities of each to fill the ship when floating at her load line draught.
Draw up a cargo plan for your calculated quantities.
Let rc=quantity of ore, and y=bales
Total deadweight 9300 tons
less coal 1200 tons
„ tea 500 „ * 1700 tons
I. Weight of ore and bales x+y = 7600 tons
Total hold capacity 411,870 cub. ft
less 500 tons tea at 110 cuk ft, 55,000 „
Space for ore and bales — 356,870 t,