Trysail
A trysail is a small triangular or square fore-and-aft rigged sail hoisted in place of a larger sail when winds are very high. The trysail provides enough thrust to maintain control of the ship. It is hoisted abaft the mainmast or, on a brig, abaft the foremast.In the Royal Navy in the late nineteenth century, the term "trysail" came to denote the main fore-and-aft sail on any mast. This included the mainsail of the "great brig" HMS Temeraire, the largest fore-and-aft sail ever used by a warship. Naval trysails were usually gaff-rigged and "loose-footed", with a spar along the head but no boom, and small auxiliary trysails continued in intermittent use into the 1920s for seakeeping and stationkeeping.
