Vessels carrying square sails are called square-rigged.  They have always two masts, usually three; each carrying three or four sails, one above the other.  These are named from the mast on which they are carried (see “Spars"); e.g., main sail, fore topsail, mizzen topgallant-sail; and also from their positions on the same mast.  Thus, from lowest up, main sail, main topsail, main topgallantsail; and main royal, if there be a fourth.  The fore and main sails are called also courses.

  The topsails were the chief battle sails, because the largest, except
  the courses, and more manageable than the courses.

  All square-rigged vessels carry fore and aft sails, three cornered,
  stretched between the bowsprit and jib-booms, and the fore topmast. 
  These sails are called jibs.

Fore and aft vessels also carry jibs; but on each upright mast they have one great sail, the size of which makes it less easily handled in an emergency, therefore less fit for fighting.  Above the big sail they have a small, light, three-cornered topsail, but this is merely a fair weather sail, useless in battle.

  Vessels of war were almost all square-rigged, with three masts.

SAILS, STUDDING.  Light square sails, for moderate weather, extended beyond the other square sails, to increase the normal spread of canvas.  Set only with a free wind, and never in battle.

SCANTLING.  The size, and consequent weight and strength, of the timbers of a vessel’s hull.

SCHOONER.  See “Vessel.”

SHAKE, to.  So to place a sail that the wind blows along it, neither filling nor backing.  The sail is thus neutralized without taking in.

SHARP-UP.  A yard is sharp-up, when turned by the braces as far as the rigging of the mast will allow.  A close-hauled course requires the yards to be sharp-up, in order that the sails may be full.

SHIP.  See “Vessel.”

SLIP.  See “Cable.”

SLOOP.  See “Vessel.”

SPARS.  A spar is a long piece of timber, cylindrical, tapering, in masts, towards one end, and in yards towards both.  Spars serve for spreading the several sails of a vessel.

  The names of spars vary with their use and position.  Chiefly, for
  ships of war, they divide into masts, yards, and booms.

A mast is an upright, and is in three connected pieces:  the lower mast, the topmast, and the top-gallant-mast.  Most ships of war had three such masts:  fore, near the bow; main, near the centre; mizzen, near the stern.

The bowsprit is also a mast; not upright, but projecting straight ahead from the bow, approaching horizontal, but inclining upwards.  Like the masts, it has three divisions:  the lower, or bowsprit proper, the jib-boom, and the flying-jib-boom.

Across the masts, horizontal, are the yards, four in number, lower, topsail, topgallant,