Cargo

Cargo is the freight with which a ship is loaded. For the ship to sail well, its cargo must be definitely known weight, and must be properly placed. Heavier articles are generally placed low down, to increase the stability of the vessel; but this principle may be carried to excess by the vessel becoming too rigid. This may cause fracture of the masts, because they do not yield sufficiently, and great stresses will also occur in the structure when it rolls at all heavily. Rolling should not disturb the centre of gravity of the cargo, otherwise there is danger of inability to recover from excessive careening. Hence the importance of storing all loose commodities compactly. Liquid cargo such as petroleum oil is carried in closed tanks.