Mainsail

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A square-rigged vessel

A mainsail is a sail rigged on the main mast of a sailing vessel.[1]

  • On a square rigged 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.[1] (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 above it.

Whereas once the mainsail was typically the largest sail, today the mainsail may be smaller than the jib or genoa; Prout catamarans typically have a mainmast stepped further aft than in a standard sloop, so that the mainsail is much smaller than the foresail.[2]

  1. ^ a b Torrey, Owen C. Jr. (1965). Sails (Seamen's Bank for Savings ed.). New York: Palmer & Oliver. pp. 7–9.
  2. ^ Note: On some mast-aft rigs, the mainsail is dispensed with altogether, producing an unconventional sail plan that traditionalist find unattractive.