The _main-gaff_ (e e), which sustains and stretches the _head_ of the _mainsail_, which is securely lashed to it by means of small seizings, or lashings.
The _main-boom_ (b b), which receives and stretches the _foot_ of the mainsail, to which it is securely lashed.
The above constitute the main spars and sails of a boat of the sloop rig.
To enable one to understand all that follows, it will be necessary to acquire a little more information concerning these spars and sails, and the names and uses of the principal ropes, sheets, &c.
As the reader faces the cut, and glances at the _mainsail_ (1), he should remember that the _head_ of the sail is that part fastened to the _gaff_; and the _foot_, that part of the sail fastened to the _boom_. The _outer-leach_, or _after-leach_, that part of the sail which extends from the end of the _gaff_ to the end of the _boom_ farthest removed from the mainmast. The _inner-leach_, or _luff_, is that part of the sail which extends from the _gaff_ to the _boom_, and is confined to the _mainmast_ by hoops that embrace it, and allow of the sail being hoisted and lowered at will.
The _clews_ of a sail are those parts which a "land-lubber" might call corners; i.e., the clews of the mainsail are four, and are situated at the junction of the _luff_ and _head_ of the sail, the _outer-leach_ and head of the sail, the _outer-leach_ and foot of the sail, and the _luff_ and _foot_ of the sail; the latter being also called the _tack_.
The mainsail, as will be observed, has also a series of regular lines crossing its surface. These are called _reef-points_, and consist of short, dangling pieces of small rope, sewed into the sail, and hanging down on either side, long enough, when the sail is lowered, to be fastened around the main-boom, and thus tie down the sail, making it smaller for rough weather, which is called "reefing." On the _outer-leach_, at the end of these rows of _reef-points_, are placed little iron rings, or _cringles_, as they are called, which are used to pass a rope through, called a _reef-pennant_, to haul the sail well out on to the boom when being reefed. The rope (a a) represents what is called the _topping-lift_, and is used to lower or hoist the _main-boom_, so as to make the sail set well in certain circumstances; or when the _main-boom_ is out over the water on one side of the boat, when running before the wind, to "_top it up_" so as to keep it out of the water when the boat rolls. It is set up by means of a small pulley, the end of the rope coming inboard through a sheave in the boom, or one fastened to its side.