BALLAST

Is a ma of weighty material placed in The bottom of a ship or ve el to give her stiffne ; that is, to increase her tendency to return to the upright position when inclined or heeled over by the force of the wind or other cause. Ballast consists of shingle (the loarse gravel of the sea-beach), stones, . In the royal navy iron ballast alone is used, in pigs of nearly 3 cwt. This has the advantage of lying in small compa ; but in consequence of its great weight it tends to give exce of stability, which renders the ve el uneasy from the suddenne of the motion: this defect is remedied by winging up the ballast, whereby its centre of gravity is raised. For the like reason in stowing the ballast it is tapered to a point at the fore and after extremities. Iron ballast, from its greater cleanline , is more healthy for the crew than that of other materials. When a ship has no other loading she is said to be in ballast. The quantitjr of ballast and the mode of its stowage differ greatly m different ve els; and the connection between the motions of a ship and her stowage has not yet been analysed sufficiently to lead to the discovery ol direct rules on these important points. [s. 132]