On a square riggedsailing vessel, a topgallant sail is the square-rigged sail or sails immediately above the topsail or topsails. It is also known as a gallant or garrant sail. Square rig is a generic type of sailing vessel in which the main horizontal spars are perpendicular to the keel of the ship. ... Wooden sailing boat Sailing is the skillful art of controlling the motion of a sailing ship or smaller boat, across a body of water using wind as the source of power. ... A topsail is a sail set above another sail; on square-rigged vessels further sails may be set above topsails. ...
A full rigged ship has two topsails and two topgallant sails per mast, so the lower topgallant sail is immediately above the upper topsail. The upper or only topgallant sail is set from the top of the topgallant mast, if there is a lower topgallant it is set from midway down the topgallant mast. A staysail set on a stay running forward and downwards from the top or midpoint of the topgallant mast is called a topgallant staysail. A full rigged ship or fully rigged ship is a square rigged sailing vessel with three or more masts, all of them square rigged. ... The mast of a sailing ship is a tall vertical pole which supports the sails. ... A staysail is a fore-and-aft rigged sail whose luff is affixed to a stay running forward (and most often but not always downwards) from a mast to the deck, the bowsprit or to another mast. ...
The square sail was mainly used on deep-water sailers, because it is a very effective and safe sail when sailing before the wind, and on long voyages you would always choose a route with as little tacking as possible.
Sailing ships are rated based on how they are rigged, and the most important aspect is where they are rigged with squaresails and where they carry fore-and-aft sails.