A spanker is either of two kinds of sail. A sail is a surface intended to generate thrust by being placed in a wind. ...
On a square rigged ship, the spanker is a gaff riggedfore-and-aft sail set from and aft of the aftmost mast. Almost all square rigs with more than one mast have one or two spankers, which evolved from the driver sail. Some also carry a topsail above the uppermost or only spanker, called the gaff sail. Square rig is a generic type of sailing vessel in which the main horizontal spars are perpendicular to the keel of the ship. ... Gaff rig is a sailing rig in which the mainsail is a four-cornered fore-and-aft rigged sail controlled at its head by a spar called the gaff. ... A fore-and-aft rig is a sailing rig consisting mainly of sails that are set along the line of the keel rather than perpendicular to it. ... A mast is a pole which holds a sail of a boat, see mast (sailing). ... A driver is a kind of sail used on some sailboats. ... A topsail is a sail set above another larger sail. ...
On a racing or cruising yacht, a spanker is an additional headsail set beside and to windward of a spinnaker when running downwind. It is often of bright colours to match the particular spinnaker with which it is designed to be used, is relatively narrow, and is sometimes called a tallboy. A yacht was originally defined as a light, fast sailing vessel used to convey important persons. ... Windward is the side of a boat into which the wind is blowing. ... A spinnaker is a special sail that is designed specifically for sailing downwind (with the wind behind the boat). ...
Even after the end of the Age of Sail in the 1850s, and the development of turretted centre-line guns, the line-of-battle technique was the one used by most navies.
Reliable steam power made warships much more maneuverable, and became the obvious choice against sail as soon as the issue of long-distance travel and re-coaling was solved.
Although made of wood and reliant on sail for most of her journeys, La Gloire was fitted with a propeller and her wooden hull was protected by a layer of thick iron armour.