A mainsail is a sail rigged on the main

mast Mast, MAST or MASt may refer to: Engineering * Mast (sailing), a vertical spar on a sailing ship * Flagmast, a pole for flying a flag * Guyed mast, a structure supported by guy-wires * Mooring mast, a structure for docking an airship * Radio mast ...

of a

sailing Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' ( sailing ship, sailboat, raft, windsurfer, or kitesurfer), on ''ice'' ( iceboat) or on ''land'' ( land yacht) over a chose ...

vessel. * On a

square rig Square rig is a generic type of sail and rigging arrangement in which the primary driving sails are carried on horizontal spars which are perpendicular, or square, to the keel of the vessel and to the masts. These spars are called '' yards'' ...

ged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. The sail's foot is normally attached to a boom. (In extremely heavy weather, the mainsail may be lowered, and a much smaller trysail hoisted in its place). Historical fore-and-aft rigs used a four-sided gaff rigged mainsail, sometimes setting a gaff

topsail A topsail ("tops'l") is a sail A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail- ...

above it. Whereas once the mainsail was typically the largest sail, today the mainsail may be smaller than the jib or genoa;

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catamarans typically have a mainmast stepped further aft than in a standard sloop, so that the mainsail is much smaller than the foresail.

Bermuda rig

The modern Bermuda rig uses a triangular mainsail

aft "Aft", in nautical terminology, is an adjective or adverb meaning towards the stern (rear) of the ship, aircraft or spacecraft, when the frame of reference is within the ship, headed at the fore. For example, "Able Seaman Smith; lie aft!" or "Wh ...

of the mast, closely coordinated with a jib for sailing upwind. A large overlapping jib or

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is often larger than the mainsail. In downwind conditions (with the wind behind the boat) a spinnaker replaces the jib. Some mainsails are "full-batten" mainsails, meaning the batten extends all the way from the mast to the leach of a sail. A partial batten extends from the leech partway to the mast. Battens enable the mainsail to project farther away from the mast. However, there is some cost associated with the battens themselves, "batten pockets" need to be sewn into the sail, and "batten cars" may be needed to allow the sail to be raised and lowered. Before Nathanael Greene Herreshoff's invention of sail tracks and slides in the 1880s, mainsails were limited in height. Traditional mainsails were held against the mast by hoops that went the full way around the mast. This meant a traditional mainsail could be raised no higher than the first point a rope or wire was required to keep the mast upright. Further mainsail area (and height) was obtained by adopting a gaff rig. A mainsail may be fixed to the boom via slugs, cars, or a bolt-rope, or may be "loose-footed," meaning it is only attached at the tack and clew.

References

{{Sail Types, state=expanded Sailing rigs and rigging

Bermuda rig

See also

References