A sail is a
tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including
sailing ships,
sailboats,
windsurfers
Windsurfing is a wind propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the aerospace and surf culture of California. Windsurfing ga ...
,
ice boat
An iceboat (occasionally spelled ice boat or traditionally called an ice yacht) is a recreational or competition sailing craft supported on metal runners for traveling over ice. One of the runners is steerable. Originally, such craft were boats ...
s, 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
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...
—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
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. ...
. 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
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
, generating propulsive force as air passes along its surface—just as an airplane wing generates
lift—which predominates over
aerodynamic drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fl ...
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.
Sails may be attached to a
mast
Mast, MAST or MASt may refer to:
Engineering
* Mast (sailing), a vertical spar on a sailing ship
* Flagmast, a pole for flying a flag
* Guyed mast, a structure supported by guy-wires
* Mooring mast, a structure for docking an airship
* Radio mast ...
, boom or other
spar or may be attached to a wire that is suspended by a mast. They are typically raised by a line, called a ''
halyard'', and their angle with respect to the wind is usually controlled by a line, called a
sheet
Sheet or Sheets may refer to:
* Bed sheet, a rectangular piece of cloth used as bedding
* Sheet of paper, a flat, very thin piece of paper
* Sheet metal, a flat thin piece of metal
* Sheet (sailing), a line, cable or chain used to control the cle ...
. In use, they may be designed to be curved in both directions along their surface, often as a result of their curved edges.
Battens may be used to extend the trailing edge of a sail beyond the line of its attachment points.
Other non-rotating airfoils that power sailing craft include
wingsail
A wingsail, twin-skin sail or double skin sail is a variable-camber aerodynamic structure that is fitted to a marine vessel in place of conventional sails. Wingsails are analogous to airplane wings, except that they are designed to provide lif ...
s, which are rigid wing-like structures, and
kites that power
kite-rigged vessels, but do not employ a mast to support the airfoil and are beyond the scope of this article.
Rigs
Sailing craft employ two types of rig, the
square rig and the
fore-and-aft rig.
The ''square rig'' carries the primary driving sails on horizontal
spars
The United States Coast Guard (USCG) Women's Reserve, also known as the SPARS (SPARS was the acronym for "Semper Paratus—Always Ready"), was the women's branch of the United States Coast Guard Reserve. It was established by the United States ...
, 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 most efficient when ''
running'' (sailing downwind).
A ''fore-and-aft rig'' consists of sails that are set along the line of the
keel rather than perpendicular to it. Vessels so rigged are described as ''fore-and-aft rigged''.
History
![Maler der Grabkammer des Menna 013](https://upload.wikimedia.org/wikipedia/commons/c/c2/Maler_der_Grabkammer_des_Menna_013.jpg)
Archaeological studies of the
Cucuteni-Trypillian culture ceramics show use of sailing boats from the sixth millennium BCE onwards.
Excavations of the
Ubaid period (c. 6000–4300 BCE) in
Mesopotamia provide direct evidence of sailing boats.
Square rigs
Sails from
ancient Egypt are depicted around 3200 BCE,
[The sea-craft of prehistory, p76, by Paul Johnstone, Routledge, 1980] where
reed boats sailed upstream against the River
Nile's current. Ancient
Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia (south-central Iraq), emerging during the Chalcolithic and early Bronze Ages between the sixth and fifth millennium BC. It is one of the cradles of c ...
ians used square rigged sailing boats at about the same time, and it is believed they established sea trading routes as far away as the
Indus valley
The Indus ( ) is a transboundary river of Asia and a trans-Himalayan river of South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in Western Tibet, flows northwest through the disputed region of Kashmir, ...
.
Greeks and
Phoenicians began trading by ship by around 1200 BCE.
V-shaped square rigs with two spars that come together at the hull were the ancestral sailing rig of the
Austronesian peoples before they developed the fore-and-aft
crab claw,
tanja and
junk rigs.
The date of introduction of these later Austronesian sails is disputed.
Lateen rigs
Lateen sails emerged by around the 2nd century CE in the Mediterranean. They did not become common until the 5th century, when there is evidence that the Mediterranean square sail (which had been in wide use throughout the
classical period) was undergoing a simplification of its rigging components. Both the increasing popularity of the lateen and the changes to the contemporary square rig are suggested to be cost saving measures, reducing the number of expensive components needed to fit out a ship.
It has been a common and erroneous presumption among maritime historians that lateen had significantly better sailing performance than the square rig of the same period. Analysis of voyages described in contemporary accounts and also in various replica vessels demonstrates that the performance of square rig and lateen were very similar. Lateen provided a cheaper rig to build and maintain, with no degradation of performance.
The lateen was adopted by Arab seafarers (usually in the sub-type: the
settee sail
The settee sail was a lateen sail with the front corner cut off, giving it a quadrilateral shape. It can be traced back to Greco-Roman navigation in the Mediterranean in late antiquity; the oldest evidence is from a late-5th-century AD ship mosaic ...
), but the date is uncertain, with no firm evidence for their use in the Western Indian Ocean before 1500 CE. There is, however, good iconographic evidence of square sails being used by Arab, Persian and Indian ships in this region in, for instance, 1519.
The popularity of the
caravel in Northern European waters from about 1440 made lateen sails familiar in this part of the world. Adittionally, lateen sails were used for the mizzen on early three-masted ships, playing a significant role in the development of the
full-rigged ship. It did not, however, provide much of the propulsive force of these vessels – rather serving as a balancing sail that was needed for some manoeuvres in some sea and wind conditions. The extensive amount of contemporary maritime art showing the lateen mizzen on 16th and 17th century ships often has the sail furled. Practical experience on the ''
Duyfken'' replica confirmed the role of the lateen mizzen.
Crab claw rigs
Austronesian invention of
catamaran
A Formula 16 beachable catamaran
Powered catamaran passenger ferry at Salem, Massachusetts, United States
A catamaran () (informally, a "cat") is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stab ...
s,
outriggers, and the bi-sparred triangular
crab claw sails enabled their ships to sail for vast distances in open ocean. It led to the
Austronesian Expansion. From Taiwan, they rapidly settled the islands of
Maritime Southeast Asia, then later sailed further onwards to
Micronesia,
Island Melanesia,
Polynesia, and
Madagascar, eventually settling a territory spanning half the globe.
![Atlas pittoresque pl 096](https://upload.wikimedia.org/wikipedia/commons/7/76/Atlas_pittoresque_pl_096.jpg)
The proto-
Austronesian
Austronesian may refer to:
*The Austronesian languages
*The historical Austronesian peoples
The Austronesian peoples, sometimes referred to as Austronesian-speaking peoples, are a large group of peoples in Taiwan, Maritime Southeast Asia, M ...
words for sail, ''lay(r)'', and some other rigging parts date to about 3000 BCE when this group began their Pacific expansion.
The absence of proto-Austronesian words for some rigging parts is evidence that the more complex sails were later developments, so calling into question the traditionalist model of Austronesian sail development.
Austronesian rigs were distinctive in that they had spars supporting both the upper and lower edges of the sails (and sometimes in between), in contrast to western rigs which only had a spar on the upper edge.
The sails were also made from salt-resistant woven leaves, usually from
pandan plants.
Crab claw sails used with
single-outrigger ships in
Micronesia,
Island Melanesia,
Polynesia, and
Madagascar were intrinsically unstable when tacking leeward. To deal with this, Austronesians in these regions developed the
shunting technique in sailing, in conjunction with uniquely reversible single-outriggers. In the rest of
Austronesia, crab claw sails were mainly for
double-outrigger (
trimaran
A trimaran (or double-outrigger) is a multihull boat that comprises a main hull and two smaller outrigger hulls (or "floats") which are attached to the main hull with lateral beams. Most modern trimarans are sailing yachts designed for recreati ...
s) and double-hulled (
catamaran
A Formula 16 beachable catamaran
Powered catamaran passenger ferry at Salem, Massachusetts, United States
A catamaran () (informally, a "cat") is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stab ...
s) boats, which remained stable even leeward.
In western
Island Southeast Asia
Maritime Southeast Asia comprises the countries of Brunei, Indonesia, Malaysia, the Philippines, Singapore, and East Timor. Maritime Southeast Asia is sometimes also referred to as Island Southeast Asia, Insular Southeast Asia or Oceanic Sout ...
, later square sails also evolved from the crab claw sail, the
tanja and the
junk rig, both of which retained the Austronesian characteristic of having more than one spar supporting the sail.
Aerodynamic forces
![Points of sail--close-hauled (right) and down wind (left)](https://upload.wikimedia.org/wikipedia/commons/c/cf/Points_of_sail--close-hauled_%28right%29_and_down_wind_%28left%29.jpg)
Aerodynamic forces on sails depend on wind speed and direction and the speed and direction of the craft. The direction that the craft is traveling with respect to the ''true wind'' (the wind direction and speed over the surface) is called the "point of sail". The speed of the craft at a given point of sail contributes to the apparent wind (V
A)—the wind speed and direction as measured on the moving craft. The apparent wind on the sail creates a total aerodynamic force, which may be resolved into ''drag''—the force component in the direction of the apparent wind—and ''lift''—the force component
normal (90°) to the apparent wind. Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Total aerodynamic force also resolves into a forward, propulsive, driving force—resisted by the medium through or over which the craft is passing (e.g. through water, air, or over ice, sand)—and a lateral force, resisted by the underwater foils, ice runners, or wheels of the sailing craft.
[
]
For apparent wind angles aligned with the entry point of the sail, the sail acts as an
airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
and lift is the predominant component of propulsion. For apparent wind angles behind the sail, lift diminishes and drag increases as the predominant component of propulsion. For a given true wind velocity over the surface, a sail can propel a craft to a higher speed, on points of sail when the entry point of the sail is aligned with the apparent wind, than it can with the entry point not aligned, because of a combination of the diminished force from airflow around the sail and the diminished apparent wind from the velocity of the craft. Because of limitations on speed through the water, displacement sailboats generally derive power from sails generating lift on points of sail that include close-hauled through broad reach (approximately 40° to 135° off the wind).
Because of low friction over the surface and high speeds over the ice that create high apparent wind speeds for most points of sail, iceboats can derive power from lift further off the wind than displacement boats.
File:Sailboat on broad reach with spinnaker.jpg, Spinnaker set for a broad reach, mobilizing both lift and drag.
File:Spinnaker trimmed for broad reach.jpg, Spinnaker cross-section trimmed for a broad reach showing air flow.
File:Amante Choate 48 photo D Ramey Logan.jpg, Spinnaker downwind, primarily mobilizing drag.
File:Symmetrical spinnaker with following apparent wind.jpg, Spinnaker cross-section with following apparent wind, showing air flow.
Types
![FMIB 47800 Differents types de Voiles](https://upload.wikimedia.org/wikipedia/commons/2/25/FMIB_47800_Differents_types_de_Voiles.jpeg)
Each rig is configured in a ''
sail plan
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.>
In the English language, ships were usually describe ...
'', appropriate to the size of the sailing craft. A sail plan is a set of drawings, usually prepared by a
naval architect This is the top category for all articles related to architecture and its practitioners.
{{Commons category, Architecture occupations
Design occupations
Architecture, Occupations ...
which shows the various combinations of sail proposed for a
sailing ship. Sail plans may vary for different wind conditions—light to heavy. Both square-rigged and fore-and-aft rigged vessels have been built with a wide range of configurations for single and multiple masts.
[
]
Types of sail that can be part of a sail plan can be broadly classed by how they are ''attached'' to the sailing craft:
*''To a stay'' – Sails attached to stays, include
jibs, which are attached to
forestays and
staysail
A staysail ("stays'l") is a fore-and-aft rigged sail whose Sail components#Edges, luff can be affixed to a stays (nautical), stay running forward (and most often but not always downwards) from a mast (sailing), mast to the deck (ship), deck, the b ...
s, which are mounted on other stays (typically wire cable) that support other masts from the bow aft.
*''To a mast'' – Fore-and-aft sails directly attached to the mast at the luff include
gaff-rigged quadrilateral and
Bermuda triangular sails.
*''To a spar'' – Sails attached to a spar include both
square sails and such fore-and-aft quadrilateral sails as
lug rig
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 ...
s,
junk and
spritsails and such triangular sails as the
lateen, and the
crab claw.
*''To a halyard'' –
Spinnaker
A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually n ...
s are the predominant sail supported solely by a halyard.
High-performance yachts, including the
International C-Class Catamaran, have used or use rigid ''wing sails'', which perform better than traditional soft sails but are more difficult to manage.
[
] A rigid wing sail was used by ''
Stars and Stripes'', the defender which won the
1988 America's Cup
The 1988 America's Cup was the 27th America's Cup regatta, and was contested between the defender, San Diego Yacht Club represented by ''Stars & Stripes H3'', and the challenger, the Mercury Bay Boating Club represented by New Zealand Challenge ...
, and by ''
USA-17'', the challenger which won the
2010 America's Cup
The 33rd America's Cup between Société Nautique de Genève defending with team Alinghi against Golden Gate Yacht Club, and their racing team BMW Oracle Racing was the subject of extensive court action and litigation, surpassing in acrimony even ...
. ''USA 17s performance during the
2010 America's Cup
The 33rd America's Cup between Société Nautique de Genève defending with team Alinghi against Golden Gate Yacht Club, and their racing team BMW Oracle Racing was the subject of extensive court action and litigation, surpassing in acrimony even ...
races demonstrated a
velocity made good Velocity made good, or VMG, is a term used in sailing, especially in yacht racing, indicating the speed of a sailboat towards (or from) the direction of the wind. The concept is useful because a sailboat cannot sail directly upwind, and thus often ...
upwind of over twice the wind speed and downwind of over 2.5 times the wind speed and the ability to sail as close as 20 degrees off the apparent wind.
[
]
Shape
![Spritsail-parts of sail (en)](https://upload.wikimedia.org/wikipedia/commons/8/8f/Spritsail-parts_of_sail_%28en%29.svg)
The shape of a sail is defined by its edges and corners in the plane of the sail, laid out on a flat surface. The edges may be curved, either to extend the sail's shape as an airfoil or to define its shape in use. In use, the sail becomes a curved shape, adding the dimension of depth or ''draft''.
*''Edges'' – The top of all sails is called the ''head'', the leading edge is called the ''luff'' on fore-and-aft sails
and on windward leech symmetrical sails, the trailing edge is the ''leech'', and the bottom edge is the ''foot''. The ''head'' is attached at the throat and peak to a gaff,
yard, or sprit. For a triangular sail the ''head'' refers to the topmost corner.
:A fore-and-aft triangular mainsail achieves a better approximation of a wing form by extending the leech aft, beyond the line between the head and clew on an arc called the ''roach'', rather than having a triangular shape. This added area would flutter in the wind and not contribute to the efficient airfoil shape of the sail without the presence of
battens.
[
] Offshore cruising mainsails sometimes have a ''hollow leech'' (the inverse of a roach) to obviate the need for battens and their ensuing likelihood of chafing the sail.
[
] The roach on a square sail design is the arc of a circle above a straight line from clew to clew at the foot of a square sail, which allows the foot of the sail to clear stays coming up the mast, as the sails are rotated from side to side.
*''Corners'' – The names of corners of sails vary, depending on shape and symmetry. In a triangular sail, the corner where the luff and the leech connect is called the ''head''.
On a square sail, the top corners are ''head cringles'', where there are grommets, called
cringle
A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the boltrope. Typically it encloses a meta ...
s.
[
] On a quadrilateral sail, the ''peak'' is the upper aft corner of the sail, at the top end of a gaff or other spar. The ''throat'' is the upper forward corner of the sail, at the bottom end of a gaff or other spar. Gaff-rigged sails, and certain similar rigs, employ two
halyards to raise the sails: the
throat halyard raises the forward, throat end of the gaff, while the
peak halyard raises the aft, peak end.
:The corner where the leech and foot connect is called the ''clew'' on a fore-and-aft sail. On a jib, the sheet is connected to the clew; on a mainsail, the sheet is connected to the boom (if present) near the clew.
''Clews'' are the lower two corners of a square sail. Square sails have
sheet
Sheet or Sheets may refer to:
* Bed sheet, a rectangular piece of cloth used as bedding
* Sheet of paper, a flat, very thin piece of paper
* Sheet metal, a flat thin piece of metal
* Sheet (sailing), a line, cable or chain used to control the cle ...
s attached to their clews like triangular sails, but the sheets are used to pull the sail down to the yard below rather than to adjust the angle it makes with the wind.
[ The corner where the leech and the foot connect is called the ''clew''.] The corner on a fore-and-aft sail where the luff and foot connect is called the ''tack'' and, on a mainsail, is located where the boom and mast connect.
:In the case of a symmetrical spinnaker
A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually n ...
, each of the lower corners of the sail is a clew. However, under sail on a given tack, the corner to which the spinnaker sheet is attached is called the ''clew'', and the corner attached to the spinnaker pole is referred to as the ''tack''. On a square sail underway, the tack is the windward clew and also the line holding down that corner.
*''Draft'' – Those triangular sails that are attached to both a mast along the luff and a boom along the foot have depth, called '' draft'', which results from the luff and foot being curved, rather than straight as they are attached to those spars. Draft creates a more efficient airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
shape for the sail. Draft can also be induced in triangular staysails
A staysail ("stays'l") is a fore-and-aft rigged sail whose Sail components#Edges, luff can be affixed to a stays (nautical), stay running forward (and most often but not always downwards) from a mast (sailing), mast to the deck (ship), deck, the b ...
by adjustment of the sheets and the angle from which they reach the sails.
Material
Sail characteristics derive, in part, from the design, construction and the attributes of the fibers, which are woven together to make the sail cloth. There are several key factors in evaluating a fiber for suitability in weaving a sail-cloth: '' initial modulus'', '' breaking strength (tenacity)'', ''creep
Creep, Creeps or CREEP may refer to:
People
* Creep, a creepy person
Politics
* Committee for the Re-Election of the President (CRP), mockingly abbreviated as CREEP, an fundraising organization for Richard Nixon's 1972 re-election campaign
Art ...
'', and '' flex strength''. Both the initial cost and its durability of the material define its cost-effectiveness over time.[
]
Traditionally, sails were made from flax
Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. Textiles made from flax are known in ...
or cotton canvas
Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags ...
.[ Materials used in sails, as of the 21st century, include nylon for spinnakers—where light weight and elastic resistance to shock load are valued—and a range of fibers, used for triangular sails, that includes Dacron, aramid fibers—including Kevlar, and other liquid crystal polymer fibers—including Vectran.][ Woven materials, like Dacron, may specified as either high or low ''tenacity'', as indicated, in part by their denier count (a unit of measure for the ]linear mass density
Linear density is the measure of a quantity of any characteristic value per unit of length. Linear mass density (titer in textile engineering, the amount of mass per unit length) and linear charge density (the amount of electric charge per unit ...
of fibers).[
]
Construction
''Cross-cut'' sails have the panels sewn parallel to one another, often parallel to the foot of the sail, and are the least expensive of the two sail constructions. Triangular cross-cut sail panels are designed to meet the mast and stay at an angle from either the warp or the weft (on the bias) to allow stretching along the luff, but minimize stretching on the luff and foot, where the fibers are aligned with the edges of the sail.[
]
''Radial'' sails have panels that "radiate" from corners in order to efficiently transmit stress and are typically higher-performance than cross-cut sails. A ''bi-radial'' sail has panels radiating from two of three corners; a ''tri-radial'' sail has panels radiating from all three corners. Mainsails are more likely to be bi-radial, since there is very little stress at the tack, whereas head sails (spinnakers and jibs) are more likely to be tri-radial, because they are tensioned at their corners.[
Higher-performance sails may be laminated, constructed directly from multiple plies of ]filament
The word filament, which is descended from Latin ''filum'' meaning " thread", is used in English for a variety of thread-like structures, including:
Astronomy
* Galaxy filament, the largest known cosmic structures in the universe
* Solar filament ...
s, fibers, taffetas, and films
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...
—instead of woven textiles—and adhered together. ''Molded sails'' are laminated sails formed over a curved mold and adhered together into a shape that does not lie flat.[
Conventional sail panels are sewn together. Sails are tensile structures, so the role of a seam is to transmit a tensile load from panel to panel. For a sewn textile sail this is done through thread and is limited by the strength of the thread and the strength of the hole in the textile through which it passes. Sail seams are often overlapped between panels and sewn with zig-zag stitches that create many connections per unit of seam length.][
]
Whereas textiles are typically sewn together, other sail materials may be ultrasonically welded—a technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics
Plastics are a wide range of synthetic polymers, synthetic or semi-synthetic materials that use polymers as a main ingredient. Their Plasticity (physics), plasticity makes it possible for plastics to be Injection moulding, moulded, Extrusion, e ...
, and especially for joining dissimilar materials.[
Sails feature reinforcements of fabric layers where lines attach at grommets or ]cringle
A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the boltrope. Typically it encloses a meta ...
s.[ A ]bolt rope
A bolt rope (Variants: "bolt-rope" and "boltrope", French: ''ralingue'', Spanish: ''relinga'', Old Norse: *''rár-línk'', comprising ''rár'' genitive of ''rá'' "rope" and ''línk'' "edge of a sail "), is the rope that is sewn at the edges of the ...
may be sewn onto the edges of a sail to reinforce it, or to fix the sail into a groove in the boom, in the mast, or in the luff foil of a roller-furling jib. They may have stiffening features, called battens, that help shape the sail, when full length,[
] or just the roach, when present.[ They may have a variety of means of reefing them (reducing sail area), including rows of short lines affixed to the sail to wrap up unused sail, as on square and gaff rigs,][
] or simply grommets through which a line or a hook may pass, as on Bermuda mainsails.[
] Fore-and-aft sails may have tell-tales—pieces of yarn, thread or tape that are affixed to sails—to help visualize airflow over their surfaces.[
Zagiel horyzont.svg, Cross-cut
Zagiel birad.svg, Bi-radial
Zagiel gwiazda.svg, Tri-radial
]
Running rigging
The lines that attach to and control sails are part of the running rigging and differ between square and fore-and-aft rigs. Some rigs shift from one side of the mast to the other, e.g. the dipping lug sail and the lateen. The lines can be categorized as those that support the sail, those that shape it, and those that control its angle to the wind.
Fore-and-aft rigged vessels
Fore-and-aft rigged vessels have rigging that supports, shapes, and adjusts the sails to optimize their performance in the wind, which include the following lines:
*''Supporting'' – ''Halyards'' raise sails and control luff tension. ''Topping lifts'' hold booms and yards aloft.[ On a gaff sail, '' brails'' run from the leech to the spar to facilitate furling.][
*''Shaping'' – ''Barber haulers'' adjust a spinnaker/jib sheeting angle inboard at right angles to the sheet with a ring or clip on the sheet attached to cordage which is secured and adjusted via fairlead and cam cleat.][
] '' Kicking straps/boom vangs'' control a boom-footed sail's leech tension by exerting downward force mid-boom.[
] ''Cunningham
Cunningham is a surname of Scottish origin, see Clan Cunningham.
Notable people sharing this surname
A–C
*Aaron Cunningham (born 1986), American baseball player
*Abe Cunningham, American drummer
* Adrian Cunningham (born 1960), Australian ...
s'' tighten the luff of a boom-footed sail by pulling downward on a cringle in the luff of a mainsail above the tack.[
] '' Downhauls'' lower a sail or a yard and can adjust the tension on the luff of a sail.[ '' Outhauls'' control the foot tension of a boom-footed sail.][
*''Adjusting angle to the wind'' – '']Sheet
Sheet or Sheets may refer to:
* Bed sheet, a rectangular piece of cloth used as bedding
* Sheet of paper, a flat, very thin piece of paper
* Sheet metal, a flat thin piece of metal
* Sheet (sailing), a line, cable or chain used to control the cle ...
s'' control angle of attack with respect to the apparent wind, the amount of leech "twist" near the head of the sail, and the foot tension of loose-footed sails.[ A '' preventer'' attaches to the end of the boom from a point near the mast to prevent an accidental gybe.][ '' Guys'' control spinnaker pole angle with respect to the apparent wind.
]
Square-rigged vessels
Square-rigged vessels require more controlling lines than fore-and-aft rigged ones, including the following.
*''Supporting'' – ''Halyards'' raise and lower the yards.[ ''Brails'' run from the leech to the spar to facilitate furling.][
] '' Buntlines'' serve to raise the foot up for shortening sail or for furling. ''Lifts'' adjust the tilt of a yard, to raise or lower the ends off the horizontal. ''Leechlines'' run to the leech
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...
(outer vertical edges) of a sail and serve to pull the leech both in and up when furling.
*''Shaping'' – ''Bowlines'' run from the leech forward towards the bow to control the weather leech, keeping it taut and thus preventing it from curling back on itself. '' Clewlines'' raise the clews to the yard above.
*''Adjusting angle to the wind'' – '' Braces'' adjust the fore and aft angle of a yard (i.e. to rotate the yard laterally, fore and aft, around the mast). ''Sheets'' attach to the clew to control the sail's angle to the wind. ''Tack
TACK is a group of archaea acronym for Thaumarchaeota (now Nitrososphaerota), Aigarchaeota, Crenarchaeota (now Thermoproteota), and Korarchaeota, the first groups discovered. They are found in different environments ranging from acidophilic the ...
s'' haul the clew of a square sail forward.
Gallery
File:Bladerider-8.jpg, International Moth on foils.
File:Funboard.jpg, Windsurfer.
File:Bladef16-1up.jpg, Formula 16
The Formula 16 (F16) sport catamaran is an ISAF recognised 5 m long beach catamaran with an asymmetric spinnaker setup.
It is actively sailed in two modes: doublehanded with a jib (''2-up''), and singlehanded without a jib (''1-up'').
Its c ...
catamaran
A Formula 16 beachable catamaran
Powered catamaran passenger ferry at Salem, Massachusetts, United States
A catamaran () (informally, a "cat") is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stab ...
.
File:DN ice boat--Ice Nine--Lake Sunapee NH.jpg, DN class ice boat
An iceboat (occasionally spelled ice boat or traditionally called an ice yacht) is a recreational or competition sailing craft supported on metal runners for traveling over ice. One of the runners is steerable. Originally, such craft were boats ...
.
File:LandYacht.jpg, Land sailing craft.
See also
;Components
*Marine canvas
Marine canvas refers to a varied array of fabrics used in the fabrication and production of awnings, covers, tarps, sunshades, signs and banners for the advertising, boating, trucking, tenting, structural and medical industries. The term "marine ca ...
*Sail Class Markings
The list of sail emblems consists of sail emblems and their class description.
File:12 Metre insigna.png, 12 Metre
File:Sharpie black.svg, 12m² Sharpie
File:125 insignia.png, 125
File:145_insignia.png, 145
File:15 Metre.png, 15 Metre
File:2.4mR ...
*Baggywrinkle
Baggywrinkle is a soft covering for cables (or any other obstructions) to reduce sail chafe. There are many points in the rig of a large sailing ship where the sails come into contact with the standing rigging; unprotected sails would soon devel ...
;Concepts
* Sail twist
;Related
* Cruising (maritime)
* SkySails
;Types of sails
* Mainsail
* Mizzen
*Wingsail
A wingsail, twin-skin sail or double skin sail is a variable-camber aerodynamic structure that is fitted to a marine vessel in place of conventional sails. Wingsails are analogous to airplane wings, except that they are designed to provide lif ...
Legend
Notes
References
Further reading
*
*
*
*
*
*
*
*
*
External links
Sailboats database: sailing yacht specifications worldwide
Sail Design Software
*
{{Authority control
Ancient Egyptian technology
Chinese inventions
Cucuteni–Trypillia culture
Marine propulsion
Sailboat components
Sailing rigs and rigging