PORT ECONOMICS 
a charge of coal in closing. Grabs are of considerable 
size: in this country they have a capacity up to 5 tons or 
so; in the United States, on the Great Lakes they are 
known as Unloaders, and are much larger, running up to 
15 or 20 tons capacity. 
Oil, being a fluid, is comparatively easily dealt with 
by means of a pipe system, with much of the pumping 
done by the ship’s own pumps, reinforced, if need be, by a 
pumping installation ashore. Flexible armoured hose 
pipe connections are required at the waterside to link up 
the piping ashore with that on board. 
General Cargo. The principal problem in regard to 
cargo handling arises with general cargo, on account of its 
extreme diversity in size, shape, weight and solidity. 
This makes it difficult to handle it by any of the systematic 
means employed in the case of bulk cargo. In certain 
cases, where a large consignment is fairly homogeneous, 
the elevator and conveyor may be utilized with advantage, 
say for chests of tea, carcases of mutton, sacks of flour, 
etc., but the generality of cargo in a ship’s holds is any- 
thing but uniform, and as stevedores usually stack it to 
suit the maximum capacity of the hold rather than the 
convenience of handling, it comes out in very irregular 
fashion—a bundle of canes or of plywood may follow a set 
of barrels, or a crate of fruit. 
This being the case, reliance has principally to be placed 
on appliances which are capable of dealing with a variety 
of goods, in whatever order they may present themselves. 
And the chief instrument for this purpose, possessing a 
remarkable adaptability to all sorts of conditions, is the 
Quay Crane, the design of which will receive some little 
notice in succeeding paragraphs. It is practically the 
only appliance capable of dealing with such unwieldy and 
miscellaneous units as bales of cotton and wool, machinery 
parts and castings, hogsheads of tobacco, pigs of lead, 
ingots of copper and tin, and lumber of varying size. 
Some kinds of goods, or their containers, are of a fragile 
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