Tack (square sail)

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The starboard tack of Prince William's forecourse. The ship is close-hauled and the sail is now controlled by the tack rather than the sheet. Parts of a square sail's tack.jpg
The starboard tack of Prince William's forecourse. The ship is close-hauled and the sail is now controlled by the tack rather than the sheet.

The tack of a square-rigged sail is a line attached to its lower corner. [1] This is in contrast to the more common fore-and-aft sail, whose tack is a part of the sail itself, the corner which is (possibly semi-permanently) secured to the vessel.

Most square-rig sails have their clews pulled down to the yard of the sail below, and hence the position of the foot of the sail is controlled by the braces of the sail below. These sails do not have tacks. The exception to this scheme is the course, which does not have a yard below it. On this sail, the sheets are led aft, and pull the clews back as well as down, taking the place of the braces of the non-existent sail below. This works perfectly well when the wind is aft of the beam, but as the ship heads further to windward the sheets become less and less effective for controlling the windward clew.

Rather than being a simple "bag of wind" held from behind, the sail must be pulled into a (fairly poor) approximation of an aerofoil, like a modern triangular sail, by hauling the windward leech as far forward and as tight as possible. The sheet is in totally the wrong position to do this and so at this point the tack is brought into play. It is a second line attached to the clew along with the sheet, but the inboard end may be taken to a suitable point well forward of the sail and pulled taut to tighten the leech into some kind of leading edge.

For ease of movement, a tack is usually a single line rather than having blocks. A common arrangement, however, is to have a separate shorter tackle which can be hooked on to apply greater force over the last few feet of movement. This is shown (though not in use) in the picture. The tackle which is just visible stowed behind the mooring bollard can be hooked into the strop or loop (labelled) on the tack in order to tighten the leach further if it should be required.

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A sail plan is a description of the specific ways that a sailing craft is rigged. Also, the term "sail plan" is a graphic depiction of the arrangement of the sails for a given sailing craft.

A tack is a nautical term both for the lower, windward corner of a sail and, separately, for the side of a sailing craft from which the wind is coming while under way—the starboard or port tack. A boat is on a starboard tack if the wind is coming over the starboard (right) side of boat with sails on port (left) side. Similarly, a boat is on a port tack if the wind is coming over the port (left) side of boat.

Jibe Basic sailing maneuver, where ship turns its stern through the wind

A jibe (US) or gybe (Britain) is a sailing maneuver whereby a sailing vessel reaching downwind turns its stern through the wind, which then exerts its force from the opposite side of the vessel. For square-rigged ships, this maneuver is called wearing ship.

Spinnaker Sail designed for sailing off the wind

A spinnaker is a sail designed specifically for sailing off the wind from a reaching course to a downwind, i.e. with the wind 90–180° off bow. The spinnaker fills with wind and balloons out in front of the boat when it is deployed, called flying. It is constructed of lightweight fabric, usually nylon, and is often brightly colored. It may be optimised for a particular range of wind angles, as either a reaching or a running spinnaker, by the shaping of the panels and seams.

Mainsail Sail rigged to the main mast of a sailing vessel

A mainsail is a sail rigged on the main mast of a sailing vessel.

Running rigging Lines that control sails

Running rigging is the rigging of a sailing vessel that is used for raising, lowering, shaping and controlling the sails on a sailing vessel—as opposed to the standing rigging, which supports the mast and bowsprit. Running rigging varies between vessels that are rigged fore and aft and those that are square-rigged.

Yard (sailing) Sail-carrying part of the rigging of a sailing ship

A yard is a spar on a mast from which sails are set. It may be constructed of timber or steel or from more modern materials like aluminium or carbon fibre. Although some types of fore and aft rigs have yards, the term is usually used to describe the horizontal spars used on square rigged sails. In addition, for some decades after square sails were generally dispensed with, some yards were retained for deploying wireless (radio) aerials and signal flags.

Sail components Features that define a (ship) sails shape and function

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Boom (sailing) In sailing, a spar along the bottom edge of a fore and aft rigged sail

In sailing, a boom is a spar (pole), along the foot of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the foot flatter when the sail angle is away from the centerline of the boat. The boom also serves as an attachment point for more sophisticated control lines. Because of the improved sail control it is rare to find a non-headsail without a boom, but lateen sails, for instance, are loose-footed. In some modern applications, the sail is rolled up into the boom for storage or reefing.

The spritsail is a four-sided, fore-and-aft sail that is supported at its highest points by the mast and a diagonally running spar known as the sprit. The foot of the sail can be stretched by a boom or held loose-footed just by its sheets. A spritsail has four corners: the throat, peak, clew, and tack. The Spritsail can also be used to describe a rig that uses a spritsail.

Clewlines and buntlines Ropes used to handle sails of a ship

Clewlines and buntlines are lines used to handle the sails of a square rigged ship.

Brace (sailing)

A brace on a square-rigged ship is a rope (line) used to rotate a yard around the mast, to allow the ship to sail at different angles to the wind. Braces are always used in pairs, one at each end of a yard (yardarm), termed port brace and starboard brace of a given yard or sail.

Crab claw sail Triangular sail with spars along upper and lower edges used by traditional Austronesians

The crab claw sail is a fore-and-aft triangular sail with spars along upper and lower edges. The crab claw sail was first developed by the Austronesian peoples some time around 1500 BC. It is used in many traditional Austronesian cultures in Island Southeast Asia, Micronesia, Island Melanesia, Polynesia, and Madagascar. Due to its extraordinary performance and ease-of-operation, it has also become very popular in modern sport sailing. It is sometimes known as the Oceanic lateen or the Oceanic sprit, even though it is not restricted to Oceania, is neither a lateen sail nor a spritsail, and has an independent older origin.

Junk rig Type of sail rig used in the Junk ships of dynastic China

The junk rig, also known as the Chinese lugsail or sampan rig, is a type of sail rig in which rigid members, called battens, span the full width of the sail and extend the sail forward of the mast.

Sail Fabric or other surface supported by a mast to allow wind propulsion

A sail is a tensile structure—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 be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments—usually in a three- or four-sided shape.

Lug sail

The lug sail, or lugsail, is a fore-and-aft, four-cornered sail that is suspended from a spar, called a yard. When raised, the sail area overlaps the mast. For "standing lug" rigs, the sail may remain on the same side of the mast on both the port and starboard tacks. For "dipping lug" rigs, the sail is lowered partially or totally to be brought around to the leeward side of the mast in order to optimize the efficiency of the sail on both tacks.

References

  1. Knight. "16. Glossary of Nautical Terms". All Things Ransome. Retrieved 7 April 2015.

Sources