Sail components include the features that define a
sail
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, ice boats, and even sail-powered land vehicles. Sails may ...
's shape and function, plus its constituent parts from which it is manufactured. A sail may be classified in a variety of ways, including by its orientation to the vessel (e.g. ''fore-and-aft'') and its shape, (e.g. ''(a)symmetrical'', ''triangular'', ''quadrilateral'', etc.). Sails are typically constructed out of flexible material that is shaped by various means, while in use, to offer an appropriate airfoil, according to the strength and apparent direction of the wind. A variety of features and fittings allow the sail to be attached to lines and spars.
Whereas conventional sails form an airfoil with one layer of fabric,
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 comprise a structure that has material on both sides to form an airfoil—much like a
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
placed vertically on the vessel—and are beyond the scope of this article.
Classifications
Sails may be classified as either ''triangular'', which describes sails that either come to one point of suspension at the top or where the sail comes to a point at the forward end, or ''quadrilateral'', which includes sails that are attached to a spar at the top and have three other sides, or as ''square''. They also may be classified as ''symmetrical'' (
square sails and symmetric
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) or ''asymmetrical'' (most other sails). Typically, asymmetrical sails perform better on
points 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. ...
closer to the wind than symmetrical sails and are designed for ''
fore-and-aft
A fore-and-aft rig is a sailing vessel rigged mainly with sails set along the line of the keel, rather than perpendicular to it as on a square rigged vessel.
Description
Fore-and-aft rigged sails include staysails, Bermuda rigged sails, ga ...
'' rigs. Symmetrical sails perform best on points of sail that are further from the wind direction.
[
]
Triangular
Triangular sails have names for each of three edges and three corners,
explained below. Rigs with such sails include
Bermuda
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lateen
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. The settee can be considered to be an associated type of the same o ...
and vessels with mixed sail plans that include
jib
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 headsail ...
s and other
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. Most triangular sails are classified as ''asymmetrical'' and ''fore and aft''; symmetric
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 ''symmetrical'' triangular sails that are designed for off-the-wind use.
[
]
Quadrilateral
Gaff
Gaff may refer to:
Ankle-worn devices
* Spurs in variations of cockfighting
* Climbing spikes used to ascend wood poles, such as utility poles
Arts and entertainment
* A character in the ''Blade Runner'' film franchise
* Penny gaff, a 19th-ce ...
, gunter, lug, junk and some sprit
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 spr ...
sails have four sides and are set ''fore and aft'' so that one edge is leading into the wind, forming an ''asymmetric'' quadrilateral shape. Naming conventions are consistent with triangular sails, except for the top edge and corners, as explained below.[
]
Square
A ''square rig
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 ...
'' is a type of sail and rigging arrangement in which the primary driving sails are carried on horizontal spar
SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...
s which are perpendicular, or square
In Euclidean geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, π/2 radian angles, or right angles). It can also be defined as a rectangle with two equal-length adj ...
, to the keel
The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...
of the vessel and to the masts—the sails themselves are not square but are ''symmetrically'' quadrilateral. These spars are called ''yards
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.914 ...
'' and their tips, beyond the last stay, are called the ''yardarms
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 such as aluminium or carbon fibre. Although some types of fore and aft rigs have yards, the term is usually used to desc ...
''. A ship mainly so rigged is called a ''square-rigger''.
Shape
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'', the trailing edge is the ''leech'', and the bottom edge is the ''foot''.
*''Head'' – The ''head'' is the upper edge of the sail, and is attached at the throat and peak to a gaff, yard
The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.914 ...
, or sprit. For a triangular sail the ''head'' refers to the topmost corner.
*''Leech'' – The aft (back) edge of a fore-and-aft sail is called the ''leech'' (also spelled ''leach''). The ''leech'' is either side edge of a symmetrical sail—triangular or square. However, once a symmetrical sail has wind blowing along its surface, whether on a reach or close-hauled, the windward leech may be called a ''luff'' (see below).
*''Luff'' – The forward (leading) edge of a fore-and-aft sail is called the ''luff'', and may be attached along a mast or a stay
Stay may refer to:
Places
* Stay, Kentucky, an unincorporated community in the US
Law
* Stay of execution, a ruling to temporarily suspend the enforcement of a court judgment
* Stay of proceedings, a ruling halting further legal process in a tri ...
. When on a reach, the windward leech of a spinnaker (symmetrical or not) is called the luff and, when on a reach or close-hauled, the windward leech of a square sail may be called the luff or the ''weather leech''.
*''Foot'' – The ''foot'' of a sail is its bottom edge. On a fore-and-aft mainsail, the foot is often attached, at the tack and clew, to a boom
Boom may refer to:
Objects
* Boom (containment), a temporary floating barrier used to contain an oil spill
* Boom (navigational barrier), an obstacle used to control or block marine navigation
* Boom (sailing), a sailboat part
* Boom (windsurfi ...
; on a square sail to a spar by clews on both ends; if no boom or spar is present, the sail is said to be "loose-footed".
Roach
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 in 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
A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields.
In the lighting industry, battens refer to linea ...
.[ 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.][
''Roach'' is a term also applied to square sail design—it is the arc of a circle above a straight line from clew to clew at the foot of a square sail, from which sail material is omitted. The greater the departure from the straight line, the greater the "hollow" in the roach. The roach 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.
*''Head'' – 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.[
]
*''Peak '' – On a quadrilateral sail, the ''peak'' is the upper aft corner of the sail, at the top end of a gaff, a sprit or other spar.
*''Throat'' – On a quadrilateral sail, 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 ''halyard
In sailing, a halyard or halliard is a line (rope) that is used to hoist a ladder, sail, flag or yard. The term ''halyard'' comes from the phrase "to haul yards". Halyards, like most other parts of the running rigging, were classically made of n ...
s'' to raise the sails: the ''throat halyard
In sailing, the throat halyard (or throat for short) is a line that raises the end of a gaff nearer to the mast, as opposed to the peak halyard which raises the end further from the mast. Such rigging was normal in classic gaff-rigged schooner
...
'' raises the forward, throat end of the gaff, while the ''peak halyard
In sailing, the peak halyard (or peak for short) is a line that raises the end of a gaff which is further from the mast, as opposed to the throat halyard which raises the end which is nearer to the mast. Such rigging was normal in classic gaff-rigg ...
'' raises the aft, peak end.
*''Clew'' – 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 '' sheets'' 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''. 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''.
*''Tack'' – The 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 ...
is the corner on a fore-and-aft sail where the luff and foot connect and, on a mainsail, is located where the boom and mast connect. 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, known as '' draft or draught'', 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.
Construction
Sails are constructed of fabrics that may be woven or manufactured as films. The sail are often assembled of multiple panels that are arrayed in a manner that transfers the load from the wind to the sail's attachment points—a combination of corners and edges—that transmits the load into the mast and powers the boat. Construction of such sails requires stitching, bonding, reinforcements and other features to achieve this. Other sails are constructed directly from fibers, filaments and films.
Materials
The characteristics of a sail are due to 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'' – The ability to resist stretching. Higher resistance is better for upwind sails.
*'' Breaking strength (tenacity)'' – Measured as a force per cross sectional area of fiber. Higher is better for sails.
*'' Creep'' – Describes the long term stretch of a fiber or fabric. A material with creep may have a superior modulus, but lose its shape over time.
*''Resistance to ultraviolet light
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
'' – Strength loss from exposure to the Sun’s UV rays measured by a standardized exposure test.
*'' Flex strength'' – Strength lost due to bending, folding, or flogging, which is frequently measured with an industry standard 50 fold test.
*''Cost-effectiveness
Cost-effectiveness analysis (CEA) is a form of economic analysis that compares the relative costs and outcomes (effects) of different courses of action. Cost-effectiveness analysis is distinct from cost–benefit analysis, which assigns a monetar ...
'' – 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
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...
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
Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic.
Nylon is a silk-like thermoplastic, generally made from petro ...
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
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...
, aramid
Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, ma ...
fibers—including Kevlar
Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s a ...
, and other liquid crystal polymer
Liquid crystal polymers (LCPs) are polymers with the property of liquid crystal, usually containing aromatic rings as mesogens. Despite uncrosslinked LCPs, polymeric materials like liquid crystal Elastomer, elastomers (LCEs) and liquid crystal n ...
fibers—including Vectran
Vectran is a manufactured fiber, spun from a liquid-crystal polymer (LCP) created by Celanese Corporation and now manufactured by Kuraray. Chemically it is an aromatic polyester produced by the polycondensation of 4-hydroxybenzoic acid and 6-hydr ...
.[
Woven materials, like Dacron, may be 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). High-tenacity Dacron comes in multiples of 220, 350 and 570 deniers, whereas low-tenacity Dacron comes in multiples of 150, 250, and 400 deniers. Sailcloth is typically heat-shrunk to tighten the weave and then receives a chemical bonding finish of melamine
Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due t ...
. Such cloth is typically specified by deniers for warp
Warp, warped or warping may refer to:
Arts and entertainment Books and comics
* WaRP Graphics, an alternative comics publisher
* ''Warp'' (First Comics), comic book series published by First Comics based on the play ''Warp!''
* Warp (comics), a ...
and fill (weft
Warp and weft are the two basic components used in weaving to turn thread or yarn into fabric. The lengthwise or longitudinal warp yarns are held stationary in tension on a frame or loom while the transverse weft (sometimes woof) is draw ...
), e.g. 220/570.[
]
Panels and laminations
Conventional sails comprise panels, which are most often stitched together, at other times adhered. There are two basic configurations, ''cross-cut'' and ''radial''. ''Cross-cut'' sails have the panels sewn parallel to one another, often parallel to the foot of the sail, and are the less 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
Bias is a disproportionate weight ''in favor of'' or ''against'' an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, ...
) to allow stretching along the luff, but minimize strutting 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 filaments, ]fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
s, taffeta
Taffeta (archaically spelled taffety or taffata) is a crisp, smooth, plain woven fabric made from silk, cuprammonium rayons, acetate, and polyester. The word is Persian (تافته) in origin and means "twisted woven". As clothing, it is used in ...
s, 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.[
Where a sail may rub against a spreader on the mast, a ]spreader patch 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.
Use and construction
Spreader patches may be placed on a jib, when it overlaps with the mast, or on the mainsail, where it ma ...
may be placed on a jib, when it overlaps with the mast, or on the mainsail, where it may interfere when furled or when the sail is backwinded against the mast.
Zagiel horyzont.svg, Cross-cut panels
Zagiel birad.svg, Bi-radial panels
Zagiel gwiazda.svg, Tri-radial panels
Stitching and bonding
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.[ Measures for seam structural attributes—shown with a typical value for a sewn seam—include:][
]
*''Breaking force'' (newtons
The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in r ...
) –
*''Elongation'' (percent) – 22%
*''Strength'' (newtons/millimetre) –
*''Modulus of elasticity'' (newtons/millimetre) –
Whereas textiles are typically sewn together, other sail materials may be ultrasonically welded—a technique whereby high-frequency ultrasonic
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...
acoustic vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
s 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
Material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geologic ...
.[
]
Edge construction
Sails have a variety of treatments at their edges, either to attach the sail to a stay, spar or mast or to prevent a free edge from fluttering or fraying.
*'' Bolt ropes'' are sewn onto the edges of the sail to reinforce them, or to fix the sail into a groove in the boom, in the mast, or in the luff foil of a roller-furling jib.
*''Leech lines'' are found on mainsails and large jibs to tighten the leech and prevent fluttering. They run through a sleeve on the leech from the head to the clew, where there is usually a clam cleat to tighten it. Occasionally, ''foot lines'' perform an analogous function on a loose-footed sail.[
]
*''UV protection panels'' are usually affixed to the leech and foot of roller furling jibs to prevent ultraviolet rays from reaching the sailcloth while the sail is not in use. These are typically a dark color to absorb the harmful rays.[
]
Reinforcements at attachment points
The corners of triangular sails are typically areas of high stress and consequently often have reinforced layers and tape radiating from, whether cross-cut or radial in construction. Their corners are always attached to a shackle
A shackle (or shacklebolt), also known as a gyve, is a U-shaped piece of metal secured with a clevis pin or bolt across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism. The term also applies to handcuffs ...
, attached to a line or spar—the halyard
In sailing, a halyard or halliard is a line (rope) that is used to hoist a ladder, sail, flag or yard. The term ''halyard'' comes from the phrase "to haul yards". Halyards, like most other parts of the running rigging, were classically made of n ...
at the head, a shackle at the tack, and the outhaul
An outhaul is a control line found on a sailboat. It is an element of the running rigging, used to attach the mainsail Parts of a sail#Corners, clew to the boom (sailing), boom and tensions the Sail components#Edges, foot of the sail. It commonly ...
at the clew. The connecting shackle runs through a grommet
Curtain grommets, used among others in shower curtains.
A grommet is a ring or edge strip inserted into a hole through thin material, typically a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets ar ...
at each of these points. There are additional points where reinforcing and grommets may occur: at the 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 ...
, a downhaul 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 ...
used to flatten a mainsail (jibs may have a similar feature), and along the foot of a Genoa jib to allow a line to lift it out of the waves. The head of a triangular sail may have a rigid ''headboard'' riveted to it in order to transfer load from the sail to the halyard.[
Square sails and gaff-rigged sails also have grommets at corners. Only the clews on a square sail take a comparatively large amount of stress, because the head is supported along the spar. Three sides of gaff-rigged sails are attached to a mast or spar.
]
Battens
A ''sail batten'' is a flexible insert in a fore-and-aft sail that provides added stiffness and definition to the sail's airfoil cross-section.[ The most common use of sail battens is in the ]roach
Roach may refer to:
Animals
* Cockroach, various insect species of the order Blattodea
* Common roach (''Rutilus rutilus''), a fresh and brackish water fish of the family Cyprinidae
** ''Rutilus'' or roaches, a genus of fishes
* California roach ...
of a mainsail. The batten extends the leech past the line that runs from the head and the clew of the sail to create a wider sail towards the top. Cruising sailboats may have four to six battens. Racing sailboats may have full-length battens, as well, that allow for better sail shape.[ Battens are also found in jibs of beach-cat catamarans.][
] Most battens are fiberglass pultrusion Pultrusion is a continuous process for manufacture of fibre-reinforced plastics with constant cross-section. The term is a portmanteau word, combining "pull" and "extrusion". As opposed to extrusion, which pushes the material, pultrusion pulls the ...
s with a thin, rectangular cross section.[
Junk rigs feature full-length battens that facilitate short-handed sail handling, including reefing. The battens are attached loosely to the mast with lines called ''batten parrels'' that allow fore-and-aft motion as the sail is controlled by individual sheets leading to multiple battens.][
]
Fittings
Sails usually have fittings attached to them that transmit force through a small area. These include grommets, which reinforce fabric at an attachment points and connections to lines; hoops and slides, which attach sails to spars; and reefing features, which may include reefing lines attached to the sail or grommets that have reefing lines running through them. Additional features include tell-tales, windows—used on dinghy sails[
]—and lettering and other graphics that include sail numbers and manufacturers logos, etc.
Hardware
Where sails are attached to a mast, spar, or stay there is some kind of connection—often it's the bolt rope running through a groove in the mast, boom, or head foil—otherwise, there is a piece of hardware involved, e.g.:
*''Gaff sails'' usually have hoops that slide up and down the mast.[
*''Bermuda mainsails'' may have slides attached to the luff that match tracks on the mast and boom. These may be attached to the luff through grommets with webbing or a nylon shackle or with webbing sewn directly on the sail.][
*''Jibs'' that are not roller-furling usually have ''hanks'', clips that attach to the stay. This applies to other ''staysails'', as well.][
Other hardware includes ''cam cleats'', used to tension luff and foot lines.][
]
Reefing points
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.[
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Tell-tales
Tell-tales are pieces of yarn, thread or tape that are affixed to sails to help visualize airflow over their surfaces. Typically, they are mounted near the luff of sails, but they are also found on the leach on some sails. To windward, a sagging tell-tale indicates still air, either from stalling (indicated on the leeward side, when the sail is sheeted in too far, compared to the apparent wind) or pinching (indicated on the windward side, when the sail isn't sheeted in far enough, compared to the apparent wind).[
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See also
* Beitass A beitass, or a stretching pole, is a wooden spar used on Viking ships that was fitted into a pocket at the lower corner of the sail
A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power t ...
* Forces on sails
Forces on sails result from movement of air that interacts with sails and gives them motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Similar principles in a rotating ...
* Glossary of nautical terms (A-L)
This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water (mostly though not necessarily on the sea). Some remain current, while many date from the 17th t ...
*
* 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. ...
* 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 ...
Notes
References
Citations
Sources
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Further reading
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* at Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...
{{DEFAULTSORT:Parts Of A Sail
Sailing rigs and rigging