Skeg
Encyclopedia
A skeg is a sternward extension of the keel
of boats and ships which have a rudder
mounted on the centre line. The term also applies to the lowest point on an outboard motor
or the outdrive of an inboard/outboard
. In more recent years, the name has been used for a fin
on a surfboard
which improves directional stability and to a moveable fin on a kayak
which adjusts the boat's centre of lateral resistance. The term is also often used for the fin on water skis in the U.S.A.
word for beard
; in Old Norse, skegg. In Icelandic
the word remains skegg, in modern Norwegian
Bokmål
and Nynorsk
, it appears as skjegg, in Swedish
, it is skägg and in Danish
, skæg. The Norwegian pronunciation of the letter combination skj is as in the English
sh. The word is related to the English shaggy. It also appears in the English place name Skegness
- 'beard point', from the way in which a series of tombolo
s forms, towards the nearby Gibraltar Point
. Here, the English pronunciation reflects a probable Danish origin, which pronounces the sk letter combination as an English speaker would expect. However, 'Skegness' is pronounced with an un-Danish hard 'g'.
is mounted on the centre-line, it is usual to hang it on gudgeon
s and pintles, the latter being upright pins and the former, rings to fit round them. Together, they form a hinge
. This naturally leaves a small gap between the sternpost
and the rudder, into which stray items like kelp
and rope
can catch, causing drag and threatening the security of the vessel's steering. In ships such as Mary Rose
, the skeg is a very small feature; a tapered extension of the keel below the leading edge of the rudder. This somewhat beard-like stern
ward extension of the keel is the basic skeg. Subsequently, the lowest pintle was commonly mounted below the rudder on a metal extension of the keel
. This helped further stabilize and protect the rudder and the name skeg was transferred to it. It used to be relatively small until screw propeller
s were introduced, when it had to reach below the screw and became a proportionately larger feature protecting both screw and rudder from damage.
On wooden vessels, the skeg may be protected from worm damage by the addition of a bug shoe
.
In more modern installations, with more than one screw, a fitting supports each propeller shaft just ahead of its screw. This is usually called a shaft bracket but the part of it which extends below the shaft bearing to protect the lower part of the propeller is also a skeg. Similarly, the protective projection of the drive casing, below the rotational axis
of the propeller of an outboard motor is another form of the skeg.
Where a yacht is designed with a fin keel, it will normally, also have a skeg-mounted rudder. This link shows the profile of such a boat. This type of skeg is pictured at the bottom of the same linked page.
, windsurfing
, and kitesurfing
the fin, sometimes known as a skeg, is located towards the rear of the surfboard
. A surf board fin improves the board's directional stability and enables directional control by banking, known as foot-steering, which involves varying the surfer's side to side weight distribution.
The fin was introduced in 1936 by Woody "Spider" Brown"
, later inventor of the modern catamaran, when he built America's first modern surfboard (i.e., capable of being surfed standing up) using principles learned during his decade of aeronautical experience. Despite this, it is usually attributed to Tom Blake. Blake claimed to have removed a skeg from a water ski then screwed it onto the bottom of his solid wood board (not capable of being surfed standing up). Brown, whose later invention of the catamaran was subsequently patented by Hobie Alter, similarly refused to contest this claim.
Small single aluminum fins first evolved into single larger wooden, then fiberglass and carbon versions. In early surf boards the beaks from Duck-Foxes were used. In time hydrodynamic improvements took place, pioneered by George Downey who also created the first removable skeg, a teak wood skeg in a teak wood box which was supposed to hold in place due to the swelling of woods in water. In modern surfing board design, the conventional set up is 3 fins, with single fins being a minority. Most windsurfing boards are single fin. However, wave boards now feature some twin fin, tri fin and quad fin designs. Directional kitesurfing boards are usually 3 fin, with 5 fin designs being used for improved upwind performance.
used on more open water such as the sea. Its purpose and use are rather different from those of the surfing skeg. In the kayak, the amount of exposure of the skeg to the water, and also its effect on the position of the boat's centre of lateral resistance (CLR), is freely adjustable by the crew. The adjustment varies the degree to which the wind affects the boat - that is, the amount of lateral movement the wind can cause by impacting the upper parts of the boat and the crew. In more conventional calculations, this would be the centre of effort of the sail area (CE). In still water, where the wind is pushing the boat sideways, a contrary force (lateral resistance) develops, resisting that movement. If the central points of the application of those two forces coincide, the boat moves steadily sideways. Otherwise, it rotates in the horizontal plane, until they are in line. By varying the CLR, it is possible to better control the boat's attitude towards the wind. Irregular flowing movement of the water complicates the issue, however. This link explains the subtleties of the kayak skeg.
, a city on the eastern coast of Yorkshire
, UK, 'skeg' is often used to mean 'look' - usually as a noun, but sometimes as a verb. Hence, "Gis a skeg," meaning, "Could I please look?"; and (as a verb) "Skeg out the state a that daft silly get," meaning "Have you noticed the eccentric nature of that person over there?" Sometimes when used as a noun, it is lengthened to 'skeggy', which should not be confused with the term 'Skeggy', a contraction of Skegness
.
The origin of this usage is unclear.
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
of boats and ships which have a rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
mounted on the centre line. The term also applies to the lowest point on an outboard motor
Outboard motor
An outboard motor is a propulsion system for boats, consisting of a self-contained unit that includes engine, gearbox and propeller or jet drive, designed to be affixed to the outside of the transom and are the most common motorized method of propelling small watercraft...
or the outdrive of an inboard/outboard
Sterndrive
A sterndrive or inboard/outboard drive is a form of marine propulsion. The engine is located inboard just forward of the transom and provides power to the drive unit located outside the hull.-Operation:...
. In more recent years, the name has been used for a fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
on a surfboard
Surfboard
A surfboard is an elongated platform used in the sport of surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding a breaking wave...
which improves directional stability and to a moveable fin on a kayak
Kayak
A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...
which adjusts the boat's centre of lateral resistance. The term is also often used for the fin on water skis in the U.S.A.
Origins
The word originates in the ScandinavianOld Norse
Old Norse is a North Germanic language that was spoken by inhabitants of Scandinavia and inhabitants of their overseas settlements during the Viking Age, until about 1300....
word for beard
Beard
A beard is the collection of hair that grows on the chin, cheeks and neck of human beings. Usually, only pubescent or adult males are able to grow beards. However, women with hirsutism may develop a beard...
; in Old Norse, skegg. In Icelandic
Icelandic language
Icelandic is a North Germanic language, the main language of Iceland. Its closest relative is Faroese.Icelandic is an Indo-European language belonging to the North Germanic or Nordic branch of the Germanic languages. Historically, it was the westernmost of the Indo-European languages prior to the...
the word remains skegg, in modern Norwegian
Norwegian language
Norwegian is a North Germanic language spoken primarily in Norway, where it is the official language. Together with Swedish and Danish, Norwegian forms a continuum of more or less mutually intelligible local and regional variants .These Scandinavian languages together with the Faroese language...
Bokmål
Bokmål
Bokmål is one of two official Norwegian written standard languages, the other being Nynorsk. Bokmål is used by 85–90% of the population in Norway, and is the standard most commonly taught to foreign students of the Norwegian language....
and Nynorsk
Nynorsk
Nynorsk or New Norwegian is one of two official written standards for the Norwegian language, the other being Bokmål. The standard language was created by Ivar Aasen during the mid-19th century, to provide a Norwegian alternative to the Danish language which was commonly written in Norway at the...
, it appears as skjegg, in Swedish
Swedish language
Swedish is a North Germanic language, spoken by approximately 10 million people, predominantly in Sweden and parts of Finland, especially along its coast and on the Åland islands. It is largely mutually intelligible with Norwegian and Danish...
, it is skägg and in Danish
Danish language
Danish is a North Germanic language spoken by around six million people, principally in the country of Denmark. It is also spoken by 50,000 Germans of Danish ethnicity in the northern parts of Schleswig-Holstein, Germany, where it holds the status of minority language...
, skæg. The Norwegian pronunciation of the letter combination skj is as in the English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
sh. The word is related to the English shaggy. It also appears in the English place name Skegness
Skegness
Skegness is a seaside town and civil parish in the East Lindsey district of Lincolnshire, England. Located on the Lincolnshire coast of the North Sea, east of the city of Lincoln it has a total resident population of 18,910....
- 'beard point', from the way in which a series of tombolo
Tombolo
A tombolo, from the Italian tombolo, derived from the Latin tumulus, meaning 'mound,' and sometimes translated as ayre , is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied island...
s forms, towards the nearby Gibraltar Point
Gibraltar Point
Gibraltar Point National Nature Reserve is an area of approximately in Lincolnshire, England.The reserve is owned by Lincolnshire County Council and East Lindsey District Council and is administered by the Lincolnshire Wildlife Trust...
. Here, the English pronunciation reflects a probable Danish origin, which pronounces the sk letter combination as an English speaker would expect. However, 'Skegness' is pronounced with an un-Danish hard 'g'.
In boats and ships
Where a vessel's rudderRudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
is mounted on the centre-line, it is usual to hang it on gudgeon
Gudgeon
A gudgeon is a circular fitting, often made of metal, which is affixed to a surface. It allows for the pivoting of another fixture. It is generally used with a pintle, which is a pin which pivots in the hole in the gudgeon. As such, a gudgeon is a simple bearing.-Winged gudgeons:A winged gudgeon...
s and pintles, the latter being upright pins and the former, rings to fit round them. Together, they form a hinge
Hinge
A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation. Hinges may be made of flexible material or of moving components...
. This naturally leaves a small gap between the sternpost
Sternpost
A sternpost is the upright structural member or post at the stern of a ship or a boat, to which are attached the transoms and the rearmost left corner part of the stern...
and the rudder, into which stray items like kelp
Kelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
and rope
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
can catch, causing drag and threatening the security of the vessel's steering. In ships such as Mary Rose
Mary Rose
The Mary Rose was a carrack-type warship of the English Tudor navy of King Henry VIII. After serving for 33 years in several wars against France, Scotland, and Brittany and after being substantially rebuilt in 1536, she saw her last action on 1545. While leading the attack on the galleys of a...
, the skeg is a very small feature; a tapered extension of the keel below the leading edge of the rudder. This somewhat beard-like stern
Stern
The stern is the rear or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite of the bow, the foremost part of a ship. Originally, the term only referred to the aft port section...
ward extension of the keel is the basic skeg. Subsequently, the lowest pintle was commonly mounted below the rudder on a metal extension of the keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
. This helped further stabilize and protect the rudder and the name skeg was transferred to it. It used to be relatively small until screw propeller
Propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...
s were introduced, when it had to reach below the screw and became a proportionately larger feature protecting both screw and rudder from damage.
On wooden vessels, the skeg may be protected from worm damage by the addition of a bug shoe
Bug shoe
The bug shoe is a length of iron bark on the bottom of a ship that goes on the bottom of the skeg to protect it from shipworms....
.
In more modern installations, with more than one screw, a fitting supports each propeller shaft just ahead of its screw. This is usually called a shaft bracket but the part of it which extends below the shaft bearing to protect the lower part of the propeller is also a skeg. Similarly, the protective projection of the drive casing, below the rotational axis
Rotation around a fixed axis
Rotation around a fixed axis is a special case of rotational motion. The fixed axis hypothesis exclude the possibility of a moving axis, and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation around more than one axis at the same...
of the propeller of an outboard motor is another form of the skeg.
Where a yacht is designed with a fin keel, it will normally, also have a skeg-mounted rudder. This link shows the profile of such a boat. This type of skeg is pictured at the bottom of the same linked page.
Surfing
In surfingSurfing
Surfing' is a surface water sport in which the surfer rides a surfboard on the crest and face of a wave which is carrying the surfer towards the shore...
, windsurfing
Windsurfing
Windsurfing or sailboarding is a surface water sport that combines elements of surfing and sailing. It consists of a board usually two to four metres long, powered by the orthogonal effect of the wind on a sail. The rig is connected to the board by a free-rotating universal joint and comprises a...
, and kitesurfing
Kitesurfing
Kitesurfing or Kiteboarding is an adventure surface water sport that has been described as combining wakeboarding, windsurfing, surfing, paragliding, and gymnastics into one extreme sport. Kitesurfing harnesses the power of the wind to propel a rider across the water on a small surfboard or a...
the fin, sometimes known as a skeg, is located towards the rear of the surfboard
Surfboard
A surfboard is an elongated platform used in the sport of surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding a breaking wave...
. A surf board fin improves the board's directional stability and enables directional control by banking, known as foot-steering, which involves varying the surfer's side to side weight distribution.
The fin was introduced in 1936 by Woody "Spider" Brown"
Woody Brown (surfer and catamaran inventor)
Woody "Spider" Brown was a surfer and designer notable for introducing modern surfing to America and for the invention of the modern catamaran.-Early life:...
, later inventor of the modern catamaran, when he built America's first modern surfboard (i.e., capable of being surfed standing up) using principles learned during his decade of aeronautical experience. Despite this, it is usually attributed to Tom Blake. Blake claimed to have removed a skeg from a water ski then screwed it onto the bottom of his solid wood board (not capable of being surfed standing up). Brown, whose later invention of the catamaran was subsequently patented by Hobie Alter, similarly refused to contest this claim.
Small single aluminum fins first evolved into single larger wooden, then fiberglass and carbon versions. In early surf boards the beaks from Duck-Foxes were used. In time hydrodynamic improvements took place, pioneered by George Downey who also created the first removable skeg, a teak wood skeg in a teak wood box which was supposed to hold in place due to the swelling of woods in water. In modern surfing board design, the conventional set up is 3 fins, with single fins being a minority. Most windsurfing boards are single fin. However, wave boards now feature some twin fin, tri fin and quad fin designs. Directional kitesurfing boards are usually 3 fin, with 5 fin designs being used for improved upwind performance.
Kayaks
A skeg is employed in the type of kayakKayak
A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...
used on more open water such as the sea. Its purpose and use are rather different from those of the surfing skeg. In the kayak, the amount of exposure of the skeg to the water, and also its effect on the position of the boat's centre of lateral resistance (CLR), is freely adjustable by the crew. The adjustment varies the degree to which the wind affects the boat - that is, the amount of lateral movement the wind can cause by impacting the upper parts of the boat and the crew. In more conventional calculations, this would be the centre of effort of the sail area (CE). In still water, where the wind is pushing the boat sideways, a contrary force (lateral resistance) develops, resisting that movement. If the central points of the application of those two forces coincide, the boat moves steadily sideways. Otherwise, it rotates in the horizontal plane, until they are in line. By varying the CLR, it is possible to better control the boat's attitude towards the wind. Irregular flowing movement of the water complicates the issue, however. This link explains the subtleties of the kayak skeg.
Yorkshire dialect
In HullKingston upon Hull
Kingston upon Hull , usually referred to as Hull, is a city and unitary authority area in the ceremonial county of the East Riding of Yorkshire, England. It stands on the River Hull at its junction with the Humber estuary, 25 miles inland from the North Sea. Hull has a resident population of...
, a city on the eastern coast of Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
, UK, 'skeg' is often used to mean 'look' - usually as a noun, but sometimes as a verb. Hence, "Gis a skeg," meaning, "Could I please look?"; and (as a verb) "Skeg out the state a that daft silly get," meaning "Have you noticed the eccentric nature of that person over there?" Sometimes when used as a noun, it is lengthened to 'skeggy', which should not be confused with the term 'Skeggy', a contraction of Skegness
Skegness
Skegness is a seaside town and civil parish in the East Lindsey district of Lincolnshire, England. Located on the Lincolnshire coast of the North Sea, east of the city of Lincoln it has a total resident population of 18,910....
.
The origin of this usage is unclear.