MAST

A long piece or system of pieces of timber, placed nearly perpendicularly to the keel of a ve el to support the yards or gaffs on which the sails are extended. When a mast is one entire piece, it is called a pole-mast; but in all large ve els it is composed of several lengths, called lower, top, and top-gallant masts: sometimes a fourth, called a royal mast. The method of supporting each mast on the one next below it is peculiar. On the sides of the lower mast, some feet below the head, are placed cheeks: on these are fixed horizontally two short pieces of wood, fore and aft, called trestle trees. Acro these at right angles are laid, bafore and abaft the mast, two or more longer and lighter pieces, called cro trees, which give the name to tlie entire system. On the mast head itself is a cap. The topmast being placed up and down, the fore side of the lower mast is swayed up between the trestle trees, and through the round or foremost hole in the cap. When raised so high that the heel of the topmast is nearly up to the surface of the cro trees, a piece of iron, called the Jid, is put through the hole in the heel for the purpose; and on this fid, of which the ends are supported on the trestle trees, the topmast rests. When Added, the topmast is stayed, and the rigging or shrouds set up to the dead eyes in the ends of the cro trees. These dead eyes pull from the lower rigging below, and thus the cro trees serve merely to extend the rigging. The topgallant is supported in the same manner on the topmast. When the mast is to be taken down, it is first raised to relieve the fid; which being drawn out, the mast is lowered. The masts are supported by a strong rope, leading forward, called the stay; by others, leading aft on each side of the ship, called, in general, backstays; and by others abreast, called shrowds, and also breast backstays. Large lower masts are composed of pieces, and have for some years been made of several lengths, about a foot or so square, and the whole supported merely by hoops at intervals. The main-mast is near the middle of the ve el, the fore-mast is that v/hich is nearest the fore part, and the mizen-mast is abaft the mainmast. The old rule for the length of the main lower mast is to take i the sum of the length of the lower deck and extreme breadth: the fore-mast is |ths of the main-mast, the mizen-mast considerably smaller. The top-mast is about |ths of the lower-mast. These rules, as well as others for the thickne es, ., are merely for convenience, based on no mechanical principle, and are by no means strictly followed. [s. 734]