BALLAST, any heavy matter, as stone, gravel, or iron, thrown into the hold of a ship, in order to make her sink a proper depth in the water, that she may be capable of carrying a sufficient quantity of sail without upsetting. There is often great difference in the proportion of ballast required to prepare ships of equal burden for a voyage; the quantity being always more or less according to the sharpness or flatness of the ship’s bottom, which seamen call the floor.

The knowledge of ballasting a ship with propriety certainly deserves the attention of the skilful mariner; for although it is known that ships in general will not carry a sufficient quantity of sail till they are laden deep enough for the surface of the water to glance nearly on the extreme breadth amidships, yet more than this general knowledge is required; since, if a vessel has a great weight of heavy ballast, as lead or iron, in the bottom, it will place the centre of gravity too low in the hold; and although this will enable her to carry a great sail, she will nevertheless sail very heavily, and run the risk of being dismasted in a gale by violent rolling. To ballast a ship properly, therefore, is the art of disposing those materials so that she maybe duly poised, and maintain a proper equilibrium on the water, without either being too stiff or too crank, which are conditions equally pernicious; for in the former case, although the ship may be fitted to carry a great sail, yet her velocity will not be proportionably increased, whilst her masts are more endangered by sudden jerks and excessive labouring; and, in the latter, she will be incapable of carrying sail, without the risk of upsetting. Stiffness, in ballasting, is occasioned by disposing a great quantity of heavy ballast, as lead or iron, in the hold, which naturally places the centre of gravity very near the keel; and that being the centre about which the vibrations are made, the lower it is placed, the more violent will be the motion of rolling. Crankness, on the other hand, is occasioned by having too little ballast, or by disposing the ship’s lading so as to raise the centre of gravity too high, which also endangers the mast in carrying sail when it blows hard. For, when the masts are deflected from the perpendicular, they strain on the shrouds in the nature of a lever, which increases as the sine of their obliquity; and a ship that loses her masts is in great danger of being lost.

The whole art of ballasting, therefore, consists in placing the centre of gravity to correspond with the trim and shape of the vessel, so as neither to be too high nor too low, neither too far forwards nor too far aft; and to lade the ship so deep, that the surface of the water may rise nearly to the extreme breadth amidships, by which means she will be enabled to carry a good sail, incline but little, and ply well to the windward.

Ships are said to be in ballast when they have no other loading. Masters of vessels are obliged to declare the quantity of ballast they bear, and to unload it at certain places. They are prohibited unloading their ballast in [7:4:321] havens, roadsteads, &c. the neglect of which prohibition has ruined many excellent ports.