Swimfin
Encyclopedia
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...
like rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
or plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
, to aid movement through the water in water sports activities such as swimming, bodyboarding
Bodyboarding
Bodyboarding is a surface water sport . The average board consists of a small, rectangular piece of hydrodynamic foam, sometimes containing a ridged spine called a 'stringer'...
, bodysurfing
Bodysurfing
Bodysurfing is the art and sport of riding a wave without the assistance of any buoyant device such as a surfboard or bodyboard. Bodysurfers typically equip themselves only with a pair of specialized swimfins that stay on during turbulent conditions and optimize propulsion.-Technique:To get on the...
, kneeboarding
Kneeboarding (surfsport)
Kneeboarding is a discipline of surfing where the rider paddles on his or her belly into a wave on a kneeboard, then rides the wave face typically on both knees. The typical kneeboard is between five and six and a half feet in length, with a wide round nose and constructed of Glassfibre over a...
, riverboarding
Riverboarding
Riverboarding is a boardsport in which the participant lies prone on their board with fins on their feet for propulsion and steering. This sport is also known as hydrospeed in Europe and as riverboarding or white-water sledging in New Zealand, depending on the type of board used...
, and various types of underwater diving
Underwater diving
Underwater diving is the practice of going underwater, either with breathing apparatus or by breath-holding .Recreational diving is a popular activity...
.
Scuba
Scuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
divers use fins to move through water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
efficiently, as human
Human
Humans are the only living species in the Homo genus...
feet being very small provide relatively poor thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
, especially when the diver is carrying equipment that increases hydrodynamic
Fluid dynamics
In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
. Very long fins and monofin
Monofin
A monofin is a type of swimfin typically used in finswimming and free-diving. It consists of a single surface attached to footpockets for both of the free-diver's feet.-History and production:...
s are used by freedivers as a means of underwater propulsion that does not require high frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
leg movement.
History
Early inventors, including Leonardo da VinciLeonardo da Vinci
Leonardo di ser Piero da Vinci was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance...
and Giovanni Alfonso Borelli
Giovanni Alfonso Borelli
Giovanni Alfonso Borelli was a Renaissance Italian physiologist, physicist, and mathematician. He contributed to the modern principle of scientific investigation by continuing Galileo's custom of testing hypotheses against observation...
, toyed with the concept of swimfins.
Benjamin Franklin
Benjamin Franklin
Dr. Benjamin Franklin was one of the Founding Fathers of the United States. A noted polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, musician, inventor, satirist, civic activist, statesman, and diplomat...
made a pair of early swimfins when he was a young boy living in Boston, Massachusetts near the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
; they were two thin pieces of wood, about the shape of an art palette
Palette (painting)
A palette , in the original sense of the word, is a rigid, flat surface on which a painter arranges and mixes paints. A palette is usually made of wood, plastic, ceramic, or other hard, inert, nonporous material, and can vary greatly in size and shape...
, which allowed him to move faster than he usually did in the water.
Modern swimfins are an invention from the Frenchman
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
Louis de Corlieu, capitaine de corvette (Lieutenant Commander
Lieutenant Commander
Lieutenant Commander is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander...
) in the French Navy
French Navy
The French Navy, officially the Marine nationale and often called La Royale is the maritime arm of the French military. It includes a full range of fighting vessels, from patrol boats to a nuclear powered aircraft carrier and 10 nuclear-powered submarines, four of which are capable of launching...
. In 1914 De Corlieu made a practical demonstration of his first prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
for a group of navy officers, Yves le Prieur
Yves le Prieur
Yves Paul Gaston Le Prieur was an officer of the French Navy and an inventor.-Adventures in the Far East:Le Prieur followed his father in joining the French navy. As an officer he served in Asia and used traditional deep sea diving equipment...
among them, who years later, in 1926, invented an early model of scuba set
Scuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
. De Corlieu left the French Navy in 1924 to fully devote himself to his invention. In April 1933 he registered a patent (number 767013, which in addition of two fins for the feet included two spoon-shaped fins for the hands) and called this equipment propulseurs de natation et de sauvetage (which can barely be translated as "swimming and rescue impulse device").
After floundering for years, even producing his fins in his own flat
Apartment
An apartment or flat is a self-contained housing unit that occupies only part of a building...
in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
, De Corlieu finally started mass production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...
of his invention in France in 1939. The same year he rented a licence to Owen P. Churchill for mass production in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. To sell his fins in the USA Owen Churchill changed the French De Corlieu's name (propulseurs) to "swimfins", which is still nowadays the current 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...
name. Churchill presented his fins to the US Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
, who decided to acquire them for its Underwater Demolition Team
Underwater Demolition Team
The Underwater Demolition Teams were an elite special-purpose force established by the United States Navy during World War II. They also served during the Korean War and the Vietnam War...
(UDT). American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
UDT and British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
COPP frogmen
Frogman
A frogman is someone who is trained to scuba diving or swim underwater in a military capacity which can include combat. Such personnel are also known by the more formal names of combat diver or combatant diver or combat swimmer....
(COPP: Combined Operations Pilotage Parties) used the "Churchill fins" during all prior underwater demining
Demining
Demining or mine clearance is the process of removing either land mines, or naval mines, from an area, while minesweeping describes the act of detecting of mines. There are two distinct types of mine detection and removal: military and humanitarian.Minesweepers use many tools in order to accomplish...
s, allowing this way in 1944 the Normandy landings. During years after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
had ended, De Corlieu spent time and efforts struggling into civil procedure
Civil procedure
Civil procedure is the body of law that sets out the rules and standards that courts follow when adjudicating civil lawsuits...
s, demanding others for patent infringement
Patent infringement
Patent infringement is the commission of a prohibited act with respect to a patented invention without permission from the patent holder. Permission may typically be granted in the form of a license. The definition of patent infringement may vary by jurisdiction, but it typically includes using or...
.
In Britain, Dunlop
Dunlop Rubber
Dunlop Rubber was a company based in the United Kingdom which manufactured tyres and other rubber products for most of the 20th century. It was acquired by BTR plc in 1985. Since then, ownership of the Dunlop trade-names has been fragmented.-Early history:...
made frogman's
British commando frogmen
Britain's commando frogman force is now the Special Boat Service , which is part of the Royal Marines. They perform various operations on land as well as in the water....
fins for World War II, but after the war saw no market for them in peacetime, and, after the first supply of war-surplus frogman's kit was used up, the British public had no access to swimfins (except for home-made attempts such as gluing marine plywood to plimsolls), until Oscar Gugen
Oscar Gugen
Oscar Gugen was a founder of the British Sub-Aqua Club.He was born in 1910 of an Austrian father and French mother. He started as a hotel kitchen hand in Austria, peeling carrots. By the age of 21 he was a hotel director in the south of France....
began importing swimfins and swimming goggles
Goggles
Goggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well,...
from France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
.
In 1946 Lillywhites
Lillywhites
Lillywhites is a sports retailer based at Piccadilly Circus, London, United Kingdom. It is currently a division of Sports Direct International.-History:...
imported about 1100 pairs of swimfins; they all sold in under 3 months.
In 1948 Luigi Ferraro, collaborating with the Italian diving equipment company Cressi-sub
Cressi-Sub
Cressi-Sub is an Italian manufacturer of scuba gear and one of the oldest underwater diving companies presently existing. Officially, the company was founded in 1946 by brothers Egidio and Nanni Cressi, although they had already begun small-scale manual production in 1943.The history of underwater...
, designed the first full-foot fin, the Rondine, named after the Italian word for swallow
Swallow
The swallows and martins are a group of passerine birds in the family Hirundinidae which are characterised by their adaptation to aerial feeding...
. A distinctive feature of Cressi's continuing Rondine full-foot fin line is the embossed outline of the bird on the foot pockets and the blades.
In 1949 Ivor Howitt or a friend of his mailed to the Dunlop Rubber Company for swimfins; Dunlop answered that they had no plans to make swimfins and saw no use for them in peacetime. Howitt made his own swimfins with innertube
Innertube
CBS Innertube is a broadband video channel launched by CBS in May 2006. The channel offers original web-only shows, as well as rebroadcasts of CBS's regular shows. This service is currently only available in the United States...
rubber stretched across a frame of stiff rubber tube.
Types
Types of fins have evolved to address the unique requirements of each community using them. Scuba diversScuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
, in particular, need large wide fins to overcome the water resistance caused by their diving equipment
Diving equipment
Diving equipment is equipment used by underwater divers for the purpose of facilitating diving activities. This may be equipment primarily intended for this purpose, or equipment intended for other puprposes which is found to be suitable for diving use....
; snorkelers
Snorkeling
Snorkeling is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped tube called a snorkel, and usually swimfins. In cooler waters, a wetsuit may also be worn...
need lightweight flexible fins; ocean swimmers, bodysurfers, and lifeguard
Lifeguard
A lifeguard supervises the safety and rescue of swimmers, surfers, and other water sports participants such as in a swimming pool, water park, or beach. Lifeguards are strong swimmers and trained in first aid, certified in water rescue using a variety of aids and equipment depending on...
s favor smaller designs that stay on their feet when moving through large surf and that make walking on the beach less awkward. In general there are two main groups of fins; full foot and open heel. Full foot fins fit like a shoe, and are designed to be worn over bare feet. If a larger size is chosen, however, full-foot fins can also be worn over socks and thin-soled booties. They are commonly used for surface swimming, and are in non adjustable sizes. Open heel have a foot pocket with an open heel area, and the fin is held to the foot by springs or straps. They can be worn over boots, and are common in diving. Many companies design fins with the same fin architecture but a choice of heel type. Other, more specific design trends are listed below.
Paddle fins
These are the most basic fins; a pair of simple stiff plastic, composite, or rubber blades that work as extensions of the feet while kicking. Some paddle fins have channels and grooves to improve power and efficiency though it has been shown that the desired effect does not occur. Paddle fins are widely believed to be the most versatile and have improved swimming economy in men. Tests in women showed a more flexible fin to be more economical, most likely due to lower leg power.Vented fins
Vented fins were first designed in 1964 by Georges BeuchatGeorges Beuchat
Georges Beuchat was a French inventor, diver, businessman and emblematic pioneer of underwater activities and founder of Beuchat.Throughout his lifetime, Georges Beuchat never ceased developing products which have significantly enhanced underwater activity as we know it today...
and commercialised as Jetfins. The Jetfin tradename and design were sold to Scubapro in the 1970’s. This style of fin is strongly favored by technical divers that use a frog kick allowing a high degree of control but sacrifice speed for low oxygen consumption. Vented fins are generally stiff paddle fins that have vents at the base of the foot pocket. The vents are intended to allow for the passage of water during the recovery stroke, but prevent passage during power strokes due to the blade angle, attempting to lessen effort during recovery and improve kick efficiency. A review and study by Pendergast et al in 2003 concluded that vented fins did not improve economy, implying that water does not pass through the vents.
Split fins
Some swimfins have the end of the blade split. The manufacturers claim that split fins operate similarly to a propellerPropeller
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...
, by creating lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
forces to move the swimmer forwards. The claim is that water flowing toward the center of the fin's "paddle" portion also gains speed as it focuses, creating a "suction" force. A 2003 study by Pendergast et al called this into question by showing that there was no significant change in performance for a particular split fin design when the split was taped over. The technology used in most commercial split fin designs is patented by the industrial design firm Nature's Wing, and is used under license.
Freediving fins
These are very similar to paddle fins, except they are far longer, and designed to work with slow stiff-legged kicks that claims to conserve energy. The vast majority are made in the "full-foot" design with very rigid footpockets, which serves to reduce weight and maximize power transfer from the leg into the fin. Freediving fins are commonly made of plastic, but are also often made from materials such as fiberglass and carbon fiberCarbon fiber
Carbon fiber, alternatively graphite fiber, carbon graphite or CF, is a material consisting of fibers about 5–10 μm in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber...
.
Monofins
A monofinMonofin
A monofin is a type of swimfin typically used in finswimming and free-diving. It consists of a single surface attached to footpockets for both of the free-diver's feet.-History and production:...
is typically used in finswimming
Finswimming
Finswimming is the progression of a swimmer using monofins or normal swimfins either on the water surface or underwater, using only muscle strength. It is a discipline of underwater sports. The competition distances are same as for swimming...
and free-diving
Free-diving
Freediving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spear fishing, freedive photography, apnea competitions and, to a degree, snorkeling...
. It consists of a single surface
Surface
In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...
attached to footpockets for both the free-diver's feet. Monofins can be made of glass fibre or carbon fibre. The diver's muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
power and swimming style, and the type of activity the monofin is used for, determine the choice of size, stiffness, and materials.
Less usual types
Open and closed heel fins are predominant, but there is a range of fins that have specialised blade attachment architecture. These include (these names are tradenames):Delfins
The Mor-Fin Corporation produces "delfins", which are swimfins that end short and to the end is attached a shape like a fish's forked homocercal caudal fin. The entire fin is based on the anatomy of various marine animals.Force fins
"Force Fin" is the trademark for fins designed, developed, manufactured and distributed by Bob Evans Designs, Inc. There are over 30 models of Force Fins. They are distinguished by an open foot pocket, that encloses only the instep, leaving the toes free so the foot can flex.Shinfins
These fins are attached to the ankle and rest against the (anatomically) upper side of the foot. The manufacturers claim this avoids leg crampCramp
Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...
s and reduces foot strain.
Flipfins
Flipfins are a open-heel swimfin designed to allow easy walking on land. Its blade and foot part are separate: the blade hinges onto the foot part at each side, roughly on the level of the metatarsal heads, and when swimming is held in line by a clip on the front of the foot part. On land or when wading the blade can be unclipped and hinged vertically so it does not interfere with walking.Training
Divers are initially taught to fin with legs straight, without excess bending of the knee, the action coming from the hips; a leg action with much knee bending like riding a bicycleBicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
is inefficient and is a common fault with divers who have not learned properly how to fin swim. Fins with differing characteristics (e.g. stiffness) may be preferred, depending on the application, and divers may have to learn a modified finning style to match.
The upper limit of a diver's fin-kick thrust force using a stationary-swimming ergometer
Ergometer
Ergometer may refer to:*Exercise machine, equipped with an apparatus for measuring the work performed by exercising*Indoor rower, called an ergometer by rowers* An instrument for measuring the amount of work done by human muscles...
was shown to be 64 newtons (14.4 lbf). The maximum thrust averaged over 20 seconds against a strain gauge has been measured as high as 192 newtons (43.2 lbf). Resistive respiratory muscle training improves and maintains endurance fin swimming performance in divers.
See also
- Human swimming
- PowerSwimPowerSwimThe PowerSwim is a device somewhat like two pairs of long thin airplane wings, one pair at each end of an axis. The axis is fastened to a scuba diver's shins by straps round his legs. The longer pair of wings is at his hips and the shorter pair is at his ankles...
, a device somewhat like two pairs of long thin airplane wings fastened to a scuba diver's hips and legs - Diving equipmentDiving equipmentDiving equipment is equipment used by underwater divers for the purpose of facilitating diving activities. This may be equipment primarily intended for this purpose, or equipment intended for other puprposes which is found to be suitable for diving use....
- Scuba equipment
- FinswimmingFinswimmingFinswimming is the progression of a swimmer using monofins or normal swimfins either on the water surface or underwater, using only muscle strength. It is a discipline of underwater sports. The competition distances are same as for swimming...