The mainsail of this cutter is indicated in red

A mainsail is the most important sail raised from the main (or only) mast of a sailing vessel. When used in a nautical sense a cutter is a small single-masted vessel Fore-and-aft rigged with two or more Headsails a Bowsprit, and The mast of a sailing ship is a tall vertical or near vertical Spar, or arrangement of Spars which supports the Sails Large ships have several masts

On a square rigged vessel, it is the lowest and largest sail on the main mast. 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

On a fore-and-aft rigged vessel, it is the lowest and largest and often the only sail rigged aft of the main mast, and is controlled along its foot by a spar known as the boom. In Sailing, a spar is also know as a round pole of wood or Metal used on a Sailing ship. In Sailing, a boom is a Spar (pole along the foot (bottom of a Fore and aft rigged Sail, that greatly improves control of the angle A sail rigged in this position without a boom is generally called a trisail, and is used in extremely heavy weather.

The modern bermuda rig uses a triangular mainsail as the only sail aft of the mast, closely coordinated with a jib for sailing upwind. The term Bermuda rig refers to a configuration of mast and Rigging for a type of Sailboat and is also known as a Marconi rig; this is the typical A jib (also spelled jibb) is a triangular Staysail set ahead of the foremost mast of a sailing boat A large overlapping jib or genoa is often larger than the mainsail. The genoa or jenny was originally referred to as the 'overlapping jib' or the Genoa jib, being named after the city of Genoa as explained below In downwind conditions (with the wind behind the boat) a spinnaker replaces the jib. A spinnaker is a special type of Sail that is designed specifically for Sailing off the wind from a reaching course to a downwind i

Traditional fore-and-aft rigs used a gaff to control the top of the mainsail, sometimes setting a topsail above it. A topsail is a Sail set above another sail on square-rigged vessels further sails may be set above topsails