in navigation, an assemblage of several breadths of canvas sewed together by the luffs, and edged round with cord, fastened to the yards of a ship, to make it drive before the wind. See SHIP.

The edges of the cloths, or pieces, of which a sail is composed, are generally sewed together with a double seam; and the whole is skirted round at the edges with a cord, called the bolt-rope.

Although the form of sails is extremely different, they are all nevertheless triangular or quadrilateral figures; or, in other words, their surfaces are contained either between three or four sides.

The former of these are sometimes spread by a yard, as lateen-sails; and otherwise by a stay, as staysails; or by a mast, as shoulder-of-mutton sails; in all which cases the foremost leech or edge is attached to the said yard, mast, or stay, throughout its whole length. The latter, or those which are four-sided, are either extended by yards, as the principal sails of a ship; or by yards and booms, as the fludding-sails, drivers, ring-tails, and all those sails which are set occasionally; or by gaffs and booms, as the main-sails of sloops and brigantines.

The principal sails of a ship (Plate CCCCXLIV, fig. 2) are the courses or lower sails; the top-sails, which are next in order above the courses; and the top-gallant sails, which are expanded above the top-sails.

The courses are the main-sail, fore-sail, and mizen main stay-sail, fore stay-sail, and mizen stay-sail; but more particularly the three first. The main-stay sail is rarely used except in small vessels.

In all quadrangular sails the upper edge is called the head; the sides or skirts are called leeches; and the bottom or lower edge is termed the foot. If the head is parallel to the foot, the two lower corners are denominated clues, and the upper corners earings.

In all triangular sails, and in those four-sided sails wherein the head is not parallel to the foot, the foremost corner at the foot is called the tack, and the after lower-corner the clue; the foremost perpendicular or sloping edge is called the fore-leech, and the hindmost the after-leech. The heads of all four-sided sails, and the fore-leeches of lateen-fails, are attached to their respective yard or gaff by a number of small cords called re-bands; and the extremities are tied to the yard-arms, or to the peak of the gaff by earings.

The stay-fails are extended upon stays between the masts, whereon they are drawn up or down occasionally, as a certain slides upon its rod, and their lower parts are stretched out by a tack and sheet. The clues of a top-fail are drawn out to the extremities of the lower yard, by two large ropes called the top-fail fleets; and the clues of the top-gallant sails are in like manner extended upon the top-fail yard-arms, as exhibited by fig. 2.

The studding-fails are set beyond the leeches or skirts of the main-sail and fore-sail, or of the top-fails or top-gallant sails of a ship. Their upper and lower edges are accordingly extended by poles run out beyond the extremities of the yards for this purpose. Those sails, however, are only fit in favourable winds and moderate weather.

All sails derive their name from the mast, yard, or stay, upon which they are extended. Thus the principal sail extended upon the main-mast is called the main-sail, d; the next above, which stands upon the main-top mast, is termed the main-top sail, e; and the highest, which is spread across the main-top-gallant mast, is named the main-top-gallant sail, f.

In the same manner there is the fore-sail, g; the fore top-sail, h; and the fore-top-gallant-sail, i; the mizen, k; the mizen top-sail, l; and mizen top-gallant-sail, m. Thus also there is the main-stay-sail, o; main-top-mast stay-sail, p; and main-top-gallant stay-sail, q; with a middle stay-sail which stands between the two last.

N.B. All these stay-fails are between the main and fore-masts.

The stay-fails between the main-mast and mizen-mast are the mizen stay-sail, r; and the mizen top-mast stay-sail, s; and sometimes a mizen top-gallant stay-sail above the latter.

The stay-fails between the foremast and the bowsprit are the fore stay-sail, t; the fore top-mast stay-sail u; and the jib, x. There is besides two square sails extended by yards under the bowsprit, one of which is called the sprit-sail, y; and the other the sprit-sail top-sail, z.

The studding-fails being extended upon the different yards of the main-mast and fore-mast, are likewise named according to their stations, the lower, top-mast, or top-gallant studding sails.

The ropes by which the lower yards of a ship are hoisted up to their proper height on the masts, are called the jears. In all other sails the ropes employed for this purpose are called haliards.

The principal sails are then expanded by haliards, sheets, and bowlines; except the courses, which are always stretched out below by a tack and sheet. They are drawn up together, or trussed up, by bunt-lines, clue-lines, d d; leech-lines, e e; reef-tackles, f f; flab-line, g; and spiling-lines. As the bunt-lines and leech-lines pass on the other side of the sail, they are expressed by the dotted lines in the figure.

The courses, top-sails, and top-gallant sails, are wheeled about the mast, so as to suit the various directions of the wind by braces. The higher studding sails, and in general all the stay-sails, are drawn down, so as to be furled, or taken in, by down-hauls.

Some experienced sail-makers contend, that it would be of much advantage if many of the sails of ships were made of equal magnitude; in which case, when necessity required it, they could be interchangeably used. For example, as the mizen top-sail is now made nearly as large as the main top-gallant sail, it would be easy to make the yards, masts, and sails, so as mutually to suit each other. The main and fore-top sails differ about two feet at head and foot, and from one to three feet in depth. These likewise could be easily made alike, and in some cases they are so. The same may be said of the main and fore top-gallant sails, and of the mizen top-gallant sail, and main fore-royal. The main-sail and fore-sail might also, with respect to their head, be made alike; but as the former has a gore at the leech, and a larger gore at the foot for clearing it of the gallows, boats, &c. which the latter has not, there might be more difficulty in arranging them. The difficulty, however, appears not to be insurmountable. These alterations, it is thought, would be extremely useful in the event of losing sails by storms of weather. Fewer sails would be thus necessary, less room would be required to stow them, and there would be less danger of confusion in taking them out. But perhaps the utility of these alterations will be more felt in the merchant-service than in the navy, which latter has always a large store of spare sails, and sufficient room to stow them in order. Thus, too, spare yards and masts might be considerably reduced in number, and yet any casual damages more easily repaired at sea. Top-mast studding sails are occasionally substituted for awnings, and might, by a very little attention in planning the rigging of a ship, be so contrived as to answer both purposes. See SHIPBUILDING.

SAIL is also a name applied to any vessel beheld at a distance under sail.

To set SAIL, is to unfurl and expand the sails upon their respective yards and stays, in order to begin the action of sailing.

To Make SAIL, is to spread an additional quantity of sail, so as to increase the ship's velocity.

To shorten SAIL, is to reduce or take in part of the sails, with an intention to diminish the ship's velocity.

To Strike SAIL, is to lower it suddenly. This is particularly used in saluting or doing homage to a superior force, or to one whom the law of nations acknowledges as superior in certain regions. Thus all foreign vessels strike to a British man of war in the British seas.