The one-third sail is an almost square sail held from above on a yard. The halyard point is located approximately one third forward of the length of the yard (hence its name).
The leading edge of the sail is almost vertical (at the front) and shorter than the trailing edge (at the rear). Thus, the yard is pricked (inclined upwards). The tack point is struck in the axis of the boat.
When tacking, the sail must be leeward. It is necessary to gambeyer. This manoeuvre consists in slightly lowering the sail and pulling on the leading edge to put the yard upright to pass it behind the mast.
The halyard is struck on the windward side of the boat. It also serves as a guying to support the mast. At the moment of gambeyer, we pass it in front of the mast to hit it again in the wind.
On some sailboats like the bisquines for example, a sail is established above the first one. They are sails of arrows (which are also in the third).
Small one-third boats are found - they then have only one mast and only one sail - but other one-third sailboats can carry several masts and several sails.
