A trysail (also known as a spencer) is a small triangular or gaff rigged

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-powered land vehicles. Sails may b ...

hoisted in place of a larger

mainsail A mainsail is a sail rigged on the main mast (sailing), mast of a sailing vessel. * 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. T ...

when winds are very high. The trysail provides enough thrust to maintain control of the ship, e.g. to avoid ship damage, and to keep the bow to the wind. It is hoisted abaft (i.e., directly behind) the

mainmast The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the median line of a ship or boat. Its purposes include carrying sails, spars, and derricks, giving necessary height to a navigation light ...

(taking the place of the much larger

) or, on a

brig A brig is a type of sailing vessel defined by its rig: two masts which are both square rig, square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the l ...

, abaft the

foremast The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the median line of a ship or boat. Its purposes include carrying sails, spars, and derricks, giving necessary height to a navigation light ...

. A trysail is analogous to a storm jib.

Royal Navy usage

In the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

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 A warship or combatant ship is a naval ship that is used for naval warfare. Usually they belong to the navy branch of the armed forces of a nation, though they have also been operated by individuals, cooperatives and corporations. As well as b ...

. Naval trysails were usually gaff-rigged and 'loose-footed', with a spar along the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

but no boom, and small auxiliary trysails continued in intermittent use into the 1920s for

seakeeping Seakeeping ability or seaworthiness is a measure of how well-suited a watercraft is to conditions when underway. A ship or boat which has good seakeeping ability is said to be very seaworthy and is able to operate effectively even in high sea stat ...

and station-keeping.

Sources

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References

{{Authority control Sailing rigs and rigging