Portal:Sails
Portal maintenance status: (October 2018)
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Introduction
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.
A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack—its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the velocity of the sailing craft. Angle of attack is often constrained by the sailing craft's orientation to the wind or point of sail. On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil, generating propulsive force as air passes along its surface—just as an airplane wing generates lift—which predominates over aerodynamic drag retarding forward motion. The more that the angle of attack diverges from the apparent wind as a sailing craft turns downwind, the more drag increases and lift decreases as propulsive forces, until a sail going downwind is predominated by drag forces. Sails are unable to generate propulsive force if they are aligned too closely to the wind.
Selected general articles
- A watersail is a sail hung below the boom. It is used mostly on gaff rig boats for extra downwind performance when racing. Often a watersail will be improvised from an unused foresail. Its psychological effects may be more effective than its aerodynamic ones. Read more...
A topsail is a sail set above another sail; on square-rigged vessels further sails may be set above topsails. Read more...
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.
Historically, spritsails were the first fore-and-aft rigs, appearing in Greco-Roman navigation in the 2nd century BC. Read more...- In sailing, an earing is a small line (rope) used to fasten the corner of a sail to a spar or yard.
In the Age of Sail, a position at the Weather Earing (the earing at the windward side of the ship) was considered a place of honor for the topmen, and on a merchant ship was the position of the second mate during reefing. Read more...
A lugger, showing a variety of lug sail types.
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 remains on the same side of the mast on both the port and starboard tacks. For "dipping lug" rigs, the sail is lowered partially to be brought around to the leeward side of the mast in order to optimize the efficiency of the sail on both tacks.
The lug sail is evolved from the square sail to improve how close the vessel can sail into the wind. Square sails, on the other hand, are symmetrically mounted in front of the mast and are manually angled to catch the wind on opposite tacks. Since it is difficult to orient square sails fore and aft or to tension their leading edges (luffs), they are not as efficient upwind, compared with lug sails. The lug rig differs from the gaff rig, also fore-and-aft, whose sail is instead attached at the luff to the mast and is suspended from a spar (gaff), which is attached to, and raised at an angle from, the mast. Read more...
Illustration of the sailing ship Kruzenshtern. The royal sail is the top tier sail, shown highlighted.
A royal is a small sail flown immediately above the topgallant on square rigged sailing ships. It was originally called the "topgallant royal" and was used in light and favorable winds.
Royal sails were normally found only on larger ships with masts tall enough to accommodate the extra canvas. Royals were introduced around the turn of the 18th century, but were not usually flown on the mizzenmast until the end of that century. It gave its name to a Dutch term for a light breeze—the Royal Sail Breeze or bovenbramzeilskoelte was a Force 2 wind on the Beaufort Scale. Read more...
A clevis fastener is a three-piece fastener system consisting of a clevis, clevis pin, and tang. The clevis is a U-shaped piece that has holes at the end of the prongs to accept the clevis pin. The clevis pin is similar to a bolt, but is only partially threaded or unthreaded with a cross-hole for a split pin. The tang is a piece that fits in the space within the clevis and is held in place by the clevis pin. The combination of a simple clevis fitted with a pin is commonly called a shackle, although a clevis and pin is only one of the many forms a shackle may take.
Clevises are used in a wide variety of fasteners used in farming equipment and sailboat rigging, as well as the automotive, aircraft and construction industries. They are also widely used to attach control surfaces and other accessories to servo controls in airworthy model aircraft. As a part of a fastener, a clevis provides a method of allowing rotation in some axes while restricting rotation in others. Read more...
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and elevators. The spool can also be called the winch drum. More elaborate designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. Some may include a solenoid brake and/or a mechanical brake or ratchet and pawl device that prevents it from unwinding unless the pawl is retracted. Read more...
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. 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. Read more...
A moonraker, also known as a moonsail, hope-in-heaven, or hopesail, is a square sail flown immediately above a skysail (see sail-plan) on the royal masts of a square rigged sailing ship. None of the four- and five-masted square rigged ships carried a moonsail.
The equivalent sail, if triangular, is called a skyscraper. Read more...
Parrel beads (also spelled parral or parrell) are an element of sailing rigging, usually deployed at the jaws of a gaff on a gaff rigged or gunter rigged craft, or on the tack of a spinnaker rigged over a furled jib. Read more...
A Flying Dutchman with the crew on the trapeze whilst the helm hikes out.
In sailing, the trapeze refers to a wire that comes from a point high on the mast, usually where the shrouds are fixed, to a hook on the crew member's harness at approximately waist level. The position when extended on the trapeze is outside the hull, braced against it (or an extension of it outwards) with the soles of the feet, facing the masthead, and clipped on by a hook on the trapeze harness. This gives the crew member more leverage to keep the boat flat by allowing the crew member's centre of gravity to balance the force of the wind in the sails.
An additional benefit is the ability to "walk" along the gunwale to balance the boat's trim fore and aft. This is necessary to prevent racing catamarans such as the Tornado from digging the bow into the water, also called pitchpoling, and causing a nosedive and often a spectacular capsize. Read more...
A jackline is a rope or wire strung from a ship's bow to stern to which a safety harness can be clipped, allowing a crewmember to move about the deck safely when there is risk of falling or being swept overboard. At sea, falling overboard is one of the leading causes of death in boating; fastening oneself to the ship with a safety harness reduces this risk.
Generally the jacklines are run from the bow to the stern on both starboard and the port side of a ship. Jack lines are used in heavy weather and in periods of reduced visibility, i.e. fog or at night. Read more...- A boomkin projecting from the bow of HMS Surprise (in center of image)
A boomkin is a short spar that may project either fore or aft on a sailing vessel, depending on its function. Traditionally, it was a strong, usually wooden spar extending forward over the bow of a Western sailing ship holding a block through which the tack of the foresail was passed; on some modern sailing yachts with long main booms it is a short spar extending aft from the stern anchoring a central backstay.
Historically, boomkins were employed in pairs, one on either side of the vessel, often canted downwards over the main head-rail. Originally butted at their inboard ends against a knighthead, bolting prevailed since the end of the 18th century. Read more...
Lazy jacks (or lazyjacks) are a type of rigging which can be applied to a fore-and-aft rigged sail to assist in sail handling during reefing and furling. They consist of a network of cordage which is rigged to a point on the mast and to a series of points on either side of the boom; these lines form a cradle which helps to guide the sail onto the boom when it is lowered, reducing the crew needed to secure the sail. Lazy jacks are most commonly associated with Bermuda rigged sails, although they can be used with gaff rigged sails and with club-footed jibs. Blocks and rings may be part of some lazyjacks.
The oyster dredging sailboats of the Chesapeake Bay, bugeyes and skipjacks, were inevitably equipped with lazy jacks, as their huge sail plans, combined with the changeable conditions on the bay, made it necessary to be able to reef quickly and with a small crew. Of late they have been revived as a feature of pleasure yachts as an alternative to roller reefing and furling. The latter methods can distort the sail, and are not compatible with battens in the reefed or furled portion of the sail. Lazy jacks are also cheaper, and can be easily applied after-market. However, they are not without disadvantages. The extra lines provide something else for the sail to foul upon when it is being raised, particularly if it is battened, and the lines and the connections between them can chafe and beat upon the sail, shortening its life and making unwanted noise. Also, unlike the roller systems, some crew member(s) must be on deck to secure the sail. Read more...
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 (shortening sail). Read more...
In sailing, a gunter is used for two main configurations of rig:- The gunter is defined as a wire that leads from one point near the end of a gaff to a point near the other end. A block travels along this wire, and a halyard is attached to this block. This allows the gaff to be raised to the vertical by a single halyard, though another halyard is required at the gaff jaws to control height.
- The gunter is created by hoops or parrel beads which secure the gaff loosely to the mast in a vertical position. A halyard is bent to the gaff jaws to control height.
Bowsprit of Falls of Clyde, showing a downward pointed dolphin striker, chain bobstays, and three furled jibs
The bowsprit of a sailing vessel is a spar extending forward from the vessel's prow. It provides an anchor point for the forestay(s), allowing the fore-mast to be stepped farther forward on the hull. Read more...- A dolphin striker (an older term for a martingale boom or simply a martingale; sometimes called a striker) is a small vertical or near vertical ancillary spar spanning between the bowsprit and martingale thereby redirecting the tension in the forward end of the martingale slightly more vertically. This vertical component is necessary to more effectively oppose the forestays' mostly upward tension on the forward end of the bowsprit than would be the case in the absence of the dolphin striker.
Schematic view of the bow of a ship, showing:
A the martingale stay, B the dolphin striker and C the bobstay.
Around 1813 some large sailing vessels experimented with double strikers: these had two downward-pointing spars forming an inverted V in the middle of the bowsprit. However, the practice was short-lived as it did not seem to provide any additional benefit. The dolphin striker's length was typically half the length of the spritsail yard or, when spreaders were used, the same length as one spreader. Read more...
Tanja sail (Malay: layar tanja) or tanja rig is a type of sail commonly used by the Malay people and other Austronesians, particularly in the Indonesian, Malaysian, and Philippine archipelago. It is also known as the tilted square sail, canted rectangular sail, or balance lug sail in English. In historical sources, tanja sail sometimes incorrectly referred as lateen sail or simply square sail. Read more...
The fore royal yard on the Prince William. Prince William's royal yards are the highest and smallest yards on the ship, are made of wood, and are "lifting yards" that can be raised along a section of the mast. Here it is in the lowered position.
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. Read more...
The downhaul is a line which is part of the rigging on a sailboat; it applies downward force on a spar or sail. The most common downhaul on a modern sailboat is attached to the spinnaker pole, though this may be referred to as the foreguy in some rigging nomenclature. The term is also commonly applied to the cunningham on the mainsail.
In a windsurfing rig, the downhaul is the primary load-bearing line which controls the sail's shape. Modern windsurfing sails incorporate a sleeve for the mast, and therefore do not have a halyard which tensions the top of the sail. The downhaul is tensioned early in the rigging process and is generally not adjustable on the water, and is therefore rather different in use than the downhaul on a sailboat. Read more...
Gaff sail, showing reefing points (20) and other features.
1. Luff 2. Foot 3. Leech 4. Head
5. Throat 5. Tack 6. Clew 7. Peak
8. Throat cringle 9. Reefing cringle
10. Tack cringle 11. Clew cringle
12. Reefing cringle 13. Peak cringle
14. Reinforcing tape 15. Bolt rope
16. Batten pocket 17. Panels
18. Reef line 19. Reefing point
20. Reefing line
Different categories of sails are reefed (reduced in size) in different manners and therefore have different fixtures that achieve shortening of sail. Traditional canvas square and gaff-rigged sails have one or more rows of reefing lines that pass through the sail, which reach around the sail that has been gathered in to reduce its size and secure the remaining unreefed sail to the spar (square rig) or boom (gaff rig). Gaff-rigged sails require an extra set of lines to secure the part of the leech that becomes the new clew. These are called reef pendents that drop through a comb on the boom, where they are secured, as needed.
Mainsails on Bermuda rigs typically have paired grommets that secure the luff and leech to the boom, as the sail is lowered to reduce its area. These become the new tack and clew. A reefing line typically runs through the reef point on the luff to quickly secure the new clew. The grommet that becomes the new tack is typically hooked onto the boom. There may be grommets along the line between the new tack and clew that allow ties to pass through around the boom. Read more...- A jib is a triangular sail that sets ahead of the foremast of a sailing vessel. Its tack is fixed to the bowsprit, to the bows, or to the deck between the bowsprit and the foremost mast. Jibs and spinnakers are the two main types of headsails on a modern boat. Read more...
- A truck is a nautical term for a wooden ball, disk, or bun-shaped cap at the top of a mast, with holes in it through which flag halyards are passed. Trucks are also used on wooden flagpoles, to prevent them from splitting.
Without a masthead truck, water could easily seep into the circular growth rings of a wooden mast. However, the grain in the truck is perpendicular to that of the mast, allowing the water to run off it. Read more...
An original cleat from HMY Britannia
In nautical contexts, a cleat is a device for securing a rope. Read more...
A deadeye is an item used in the standing and running rigging of traditional sailing ships. It is a smallish round thick wooden (usually lignum vitae) disc with one or more holes through it, perpendicular to the plane of the disc. Single and triple-hole deadeyes are most commonly seen. The three-holed blocks were called deadeyes because the position of the three holes resemble the eye and nose sockets of a sheep's skull.
Single deadeyes (or bull's eyes) are used to guide and control a line and, particularly in older vessels, to change its direction. More modern systems would use a block for this purpose but in traditional rigs with many lines to deal with, designed when blocks were relatively expensive to make, a deadeye provided an acceptable compromise. When blocks came into common use for adjusting running rigging, deadeyes continued to be used for tensioning standing rigging. Read more...
Originally found on sailing ships, the lateen sail is used today in a slightly different form on small boats such as the highly popular Sunfish.
A lateen (from French latine, meaning "Latin") or latin-rig is a triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction.
Dating back to Roman navigation, the lateen became the favorite sail of the Age of Discovery, mainly because it allows a boat to tack "against the wind." It is common in the Mediterranean, the upper Nile River, and the northwestern parts of the Indian Ocean, where it is the standard rig for feluccas and dhows. The lateen is used today in a slightly different form on small recreational boats like the Sailfish and Sunfish, but is still used as a working rig by coastal fishermen in the Mediterranean. Read more...
Square rig is a generic type of sail and rigging arrangement in which the primary driving sails are carried on horizontal spars which are perpendicular, or square, to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship mainly so rigged is called a square-rigger.
The square rig is aerodynamically the most efficient running rig (i.e., sailing downwind), and stayed popular on ocean-going sailing ships until the end of the Age of Sail. The last commercial sailing ships, windjammers, were usually square-rigged four-masted barques. Read more...
A tell-tale, also known as a tell-tail, in a nautical or sailing context, is a piece of yarn or fabric attached to a stay, any of several wires which hold a mast in place on a sailboat. they are used in pairs, on each side of the jib; there will be one tell-tail on the port stay and one on a starboard stay.
Tell-tales can also be attached to a sail, used as a guide when trimming (adjusting) a sail. On the mainsail tell-tales may be placed on the leech (aft edge) and when trimmed properly should be streaming backwards while on a beat (upwind). When placed on the luff (forward or mast edge of the mainsail) they are used to indicate that the sail is luffing or coming head to wind. The solution is to bear away from the wind or sheet in. On the jib there may be tell-tales on both sides of the luff of the sail. As a general guide, the windward tell-tale should stream aft (backwards) with an occasional lift, the leeward front tell-tail should stream aft when on a beat to windward. If one tell-tail begins to spiral, it is indicating the sail has detached air flow on that side. To correct this the sail needs to move towards the opposite side. "Tiller to tatteling tail" is a good phrase to remember which direction to push the tiller when the tail is spiraling. Alternatively, the sail itself can be sheeted in or out towards the tell-tale which is not streaming. Read more...- The nautical term "stay mouse" refers to an antiquated part of a sailing vessel's standing rigging. On all sailing ships built before about the 19th century, the stays were of natural cords. These lines were looped around the top of each section of the wooden masts using a spliced loop or seized loop in their ends. During the 16th century some riggers began to attach stays by splicing or seizing only a small loop into the end of the stay then passing the rope's tail around the mast and back through the small loop, like a slip-knot. To prevent this from slipping tightly around the mast when in use, a strong bulge was built into the standing part of the rope that could not fit through the small loop. This bulge was called a mouse or stay mouse.
As first galvanised and then stainless steel standing rigging replaced natural fibres, and steel and aluminium replaced wood for masts, the need for these niceties died out. Knowledge of, and interest in, these technologies is kept alive by classic boat and historic ship enthusiasts, as well as by model makers the world over. Read more...
Sailcloth encompasses a wide variety of materials that span those from natural fibers, such as flax, hemp or cotton in various forms of sail canvas, to synthetic fibers, including nylon, polyester, aramids, and carbon fibers in a variety of woven, spun and molded textiles. Read more...
Gaff rig is a sailing rig (configuration of sails, mast and stays) in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar (pole) called the gaff. Because of the size and shape of the sail, a gaff rig will have running backstays rather than permanent backstays.
The gaff enables a fore and aft sail to be four sided, rather than triangular. A gaff rig typically carries 25 percent more sail than an equivalent bermudian rig for a given hull design. Read more...
A small schooner with its parts enumerated; the topping lift is shown joining near the end of the boom and the top of the main mast.
The topping lift (more rarely known as an uphaul) is a line which applies upward force on a boom on a sailboat.
Part of the running rigging, topping lifts are primarily used to hold a boom up when the sail is lowered. [1] This line would run from near the free end of the boom(s) forward to the top of the mast. The line may be run over a block at the top of the mast and down to the deck to allow it to be adjusted. For small booms, the topping lift may be run from end of the boom to the backstay or next mast aft. When the sail is raised again, the topping lift is loosened or removed. On sailboats used for racing, boom lift function is frequently incorporated into the boom vang system, to reduce the number of lines aloft. Allowing the vang to take this function also simplifies operation of the boat. [2] Read more...
Ljungström rig is the name for the sailing rig designed by Swedish engineer Fredrik Ljungström with double main sails and rotating mast, but without boom, foresail, forestay and shroud. The early models of the Ljungström sailboat had a stern stay but this was omitted around 1945, before the model 12 (Vingen 12).
The Ljungström rig is competitive towards the competing rigs from that time when close hauled and full run but is lacking at beam reach and broad reach. Its main purpose and advantage is, however, safety and ease of handling. Read more...
In sailing, a cunningham or cunningham's eye is a type of downhaul used on a Bermuda rigged sailboat to change the shape of a sail. It is named after its inventor, Briggs Cunningham, a victorious America's Cup skipper and yacht builder.
The cunningham differs from a typical downhaul in the way that it attaches to the sail. The system usually consists of a line which is secured at one end to the mast or boom below the foot of the mainsail. It is then passed through a cringle in the luff of the sail near the foot, but above the tack, and then led down on the other side to a fitting on the mast or boom or on deck. Read more...- A screacher is a sail that combines the features of a spinnaker and a reacher.
Its similarity with a spinnaker is that it is not attached to a stay along its luff, and typically has a slightly larger curvature than a genoa. Luff shape and tension is maintained by the halyard and a bolt rope which is woven into the sail itself, and it is this stiff tensioned rope which allows the sail to be furled on itself. In addition, many screachers are gybed by allowing the sail to fly free and pass in front of the bolt rope and invert, much in the same way that an asymmetrical spinnaker is gybed. Tacking with a screacher may require furling and re-setting. The similarity with a genoa is that it is typically a white sail, and the clews always overlap the mast. Read more...
A genoa sail is a type of large jib or staysail that extends past the mast and so overlaps the main sail when viewed from the side, sometimes eliminating it.
It was originally called an "overlapping jib" and later a Genoa jib. It is used on single-masted sloops and twin-masted boats such as yawls and ketches. Its larger surface area increases the speed of the craft in light to moderate winds; in high wind, a smaller jib is usually substituted, and downwind a spinnaker may be used. Read more...- A spreader patch is a fabric reinforcement at a point on a sail where it is likely to rub with the spreader on a mast. Read more...
Several different types of block connections as used on sailing ships, including the regular shackle, upset shackle, reverse shackle, reverse upset shackle, swivel jaw, swivel eye made round or oval, loose front hook, loose swivel hook,stiff swivel hook, loose side hook, stiff front hook, and side sister hook.
In sailing, a block is a single or multiple pulley. One or a number of sheaves are enclosed in an assembly between cheeks or chocks. In use, a block is fixed to the end of a line, to a spar, or to a surface. A line (rope) is reeved through the sheaves, and maybe through one or more matching blocks at some far end, to make up a tackle.
The purchase of a tackle refers to its mechanical advantage. In general the more sheaves in the blocks that make up a tackle, the higher its mechanical advantage. The matter is slightly complicated by the fact that every tackle has a working end where the final run of rope leaves the last sheave. More mechanical advantage can be obtained if this end is attached to the moving load rather than the fixed end of the tackle. Read more...
Clewlines and buntlines are lines used to handle the sails of a square rigged ship.
Although the common perception of a traditionally rigged ship is that the sails are handled from "up in the rigging", the majority of the work is actually carried out from the deck. In particular, when sailors go aloft to stow the square sails by bundling them up and tying them to the yard (with gaskets) they don't have to pull the whole weight of the sail up towards them. That work has already been carried out from the deck using the clewlines and the buntlines. Read more...
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Selected images
Lug-rigged vessel (lugger).
Sail angles of attack and resulting (idealized) flow patterns that provide propulsive lift.
Square rigged frigate.
Cross-cut genoa jib with sail components.
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Topics
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| Rigs | |||||||||
| Sails (sail plan, course, extra) |
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| Sail components | |||||||||
| Spars (Jury rigging) |
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| Rigging types and components |
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