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Swimfins, swim fins, diving fins, or flippers are
fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
like accessories worn on the feet, legs or hands and made from
rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...
,
plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
,
carbon fiber Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
or combinations of these materials, to aid movement through the water in
water sports Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ...
activities such as
swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that r ...
,
bodyboarding Bodyboarding is a water sport in which the surfer rides a bodyboard on the crest, face, and curl of a wave which is carrying the surfer towards the shore. Bodyboarding is also referred to as ''Boogieboarding'' due to the invention of the "Boogie ...
,
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 often equip themselves with a pair of swimfins that aid propulsion and help the bodysurfer catch, ride an ...
, float-tube fishing,
kneeboarding Kneeboarding is an aquatic sport where the participant is towed on a buoyant, convex, and hydrodynamically shaped board at a planing speed, most often behind a motorboat. Kneeboarding on a surf style board with fin(s) is also done in waves at ...
,
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, dep ...
,
scuba diving Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Chris ...
,
snorkeling Snorkeling ( British and Commonwealth English spelling: snorkelling) is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped breathing tube called a snorkel, and usually swimfins. In cooler waters, a ...
,
spearfishing Spearfishing is a method of fishing that involves impaling the fish with a straight pointed object such as a spear, gig or harpoon. It has been deployed in artisanal fishing throughout the world for millennia. Early civilisations were familia ...
,
underwater hockey Underwater hockey (UWH), (also known as Octopush in the United Kingdom) is a globally played limited-contact sport in which two teams compete to manoeuvre a puck across the bottom of a swimming pool into the opposing team's goal by propelling ...
,
underwater rugby Underwater rugby (UWR) is an underwater team sport. During a match two teams try to score a negatively buoyant ball (filled with saltwater) into the opponents’ goal at the bottom of a swimming pool. It originated from within the physical f ...
and various other types of
underwater diving Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context ...
. Swimfins help the wearer to move through
water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
more efficiently, as human feet are too small and inappropriately shaped to provide much
thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...
, especially when the wearer is carrying equipment that increases
hydrodynamic In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) and ...
drag. Very long fins and
monofin A monofin is a type of swimfin typically used in underwater sports such as finswimming, free-diving and underwater orienteering. It consists of a single or linked control surface (fluid dynamics), surfaces attached to both of the diver's feet, ...
s used by freedivers as a means of underwater propulsion do not require high-
frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
leg movement. This improves efficiency and helps to minimize oxygen consumption. Short, stiff-bladed fins are effective for short bursts of acceleration and maneuvering, and are useful for bodysurfing.


History

Early inventors, including
Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially res ...
and
Giovanni Alfonso Borelli Giovanni Alfonso Borelli (; 28 January 1608 – 31 December 1679) was a Renaissance Italian physiologist, physicist, and mathematician. He contributed to the modern principle of scientific investigation by continuing Galileo's practice of testi ...
, toyed with the concept of swimfins, taking their inspiration from
duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...
s' feet.
Benjamin Franklin Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading inte ...
made a pair of early swimfins (for hands) when he was a young boy living in Boston, Massachusetts near the
Charles River The Charles River ( Massachusett: ''Quinobequin)'' (sometimes called the River Charles or simply the Charles) is an river in eastern Massachusetts. It flows northeast from Hopkinton to Boston along a highly meandering route, that doubles b ...
; they were two thin pieces of wood, about the shape of an artist's palette, which allowed him to move faster than he usually did in the water. Modern swimfins are an invention by the Frenchman
Louis de Corlieu Louis Marie de Corlieu, born November 23, 1888 in Bourges and died October 19, 1967 (1971?) in Paris, was a French naval officer and inventor of the swimfin. Military service He served as Capitaine de corvette (lieutenant commander) in the French ...
, ''capitaine de corvette'' (
Lieutenant Commander Lieutenant commander (also hyphenated lieutenant-commander and abbreviated Lt Cdr, LtCdr. or LCDR) is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander. The corresponding rank i ...
) in the
French Navy The French Navy (french: Marine nationale, lit=National Navy), informally , is the maritime arm of the French Armed Forces and one of the five military service branches of France. It is among the largest and most powerful naval forces in t ...
. In 1914 Corlieu made a practical demonstration of his first
prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
for a group of navy officers, Yves le Prieur among themAlain Perrier, ''250 réponses aux questions du plongeur curieux'', Éditions du Gerfaut, Paris, 2008, (p.65, in French) who, years later in 1926, invented an early model of
scuba set A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. ''Scuba'' is an anacronym for self-contained underwater breathing ...
. 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 to 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 be translated literally as "swimming and rescue propulsion device"). After struggling for years, even producing his fins in his own
flat Flat or flats may refer to: Architecture * Flat (housing), an apartment in the United Kingdom, Ireland, Australia and other Commonwealth countries Arts and entertainment * Flat (music), a symbol () which denotes a lower pitch * Flat (soldier), ...
in
Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
, Louis de Corlieu finally started
mass production Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized products in a constant flow, including and especially on assembly lines. Together with job production and batch ...
of his invention in France in 1939. The same year he issued a licence to
Owen Churchill Owen Porter Churchill (March 8, 1896 – November 22, 1985) was an American sailor who competed in the 1932 Summer Olympics. In 1932 he was a crew member of the American boat ''Angelita'' which won the gold medal in the 8 metre class. ...
for mass production in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. To sell his fins in the USA Owen Churchill changed the French Corlieu's name (''propulseurs'') to "swimfins", which is still the common
English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...
name. Churchill presented his fins to the
US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...
, which decided to acquire them for its
Underwater Demolition Team Underwater Demolition Teams (UDT), or frogmen, were amphibious units created by the United States Navy during World War II with specialized non-tactical missions. They were predecessors of the navy's current SEAL teams. Their primary WWII func ...
(UDT).
American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...
UDT and
British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...
COPP
frogmen A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes military, and in some European countries, police work. Such personnel are also known by the more formal names of combat diver, comb ...
(COPP:
Combined Operations Pilotage Parties Combined Operations Headquarters was a department of the British War Office set up during Second World War to harass the Germans on the European continent by means of raids carried out by use of combined naval and army forces. History The comm ...
) used the "Churchill fins" during all prior underwater
demining Demining or mine clearance is the process of removing land mines from an area. In military operations, the object is to rapidly clear a path through a minefield, and this is often done with devices such as mine plows and blast waves. By contra ...
s, thus enabling in 1944 the
Normandy landings The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as ...
. During the years after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
had ended, De Corlieu spent time and efforts struggling in
civil procedure Civil procedure is the body of law that sets out the rules and standards that courts follow when adjudicating civil lawsuits (as opposed to procedures in criminal law matters). These rules govern how a lawsuit or case may be commenced; what ki ...
s, suing others for
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 v ...
. In Britain, Dunlop made frogman's 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 Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
to
plimsolls A pump or plimsoll (British English; see other names below) is a type of athletic shoe with a canvas upper and rubber sole developed initially as beachwear. Pumps have solid rubber soles about 8 or 9 mm thick, to which the canvas is glued with ...
), until
Oscar Gugen Norbert Oscar Gugen (20 January 1910 – 19 March 1992) co-founded the British Sub-Aqua Club, "the largest and most successful diving club in the world", and the partnership E. T. Skinner & Co. Ltd., which became Typhoon International, "the world ...
began importing swimfins and swimming
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 ...
from
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
. In 1946
Lillywhites Lillywhites is a sports retailer based at Piccadilly Circus, London, United Kingdom. It is a division of Frasers Group. History In the 19th century, several members of the Lillywhite family were leading cricketers; another, Fred Lillywhite, o ...
imported about 1,100 pairs of swimfins; they all sold in under 3 months. In 1948 Luigi Ferraro, collaborating with the Italian diving equipment company
Cressi-sub Cressi is one of the largest manufacturers of water sports equipment in the world serving the scuba dive, Snorkeling, snorkel and Human swimming, swim industries. The company's five divisions cover four markets—scuba diving, snorkeling, spearfi ...
, designed the first full-foot fin, the Rondine, named after the Italian word for
swallow The swallows, martins, and saw-wings, or Hirundinidae, are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...
. 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. After The Amphibians Club, the UK's first post-war sport diving club, was founded by
Ivor Howitt Ivor is an English masculine given name derived either directly from the Norse ''Ívarr'', or from Welsh (which spells it ''Ifor''), Irish (sometimes ''Ibar''), or Scottish, all of which likely derive it also from the original Norse form.The Oxford ...
and friends in 1948 in
Aberdeenshire Aberdeenshire ( sco, Aiberdeenshire; gd, Siorrachd Obar Dheathain) is one of the 32 Subdivisions of Scotland#council areas of Scotland, council areas of Scotland. It takes its name from the County of Aberdeen which has substantially differe ...
, "swim fins were made by wiring stiff rubber piping each side of a flap of
inner tube An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve stem, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the ...
rubber. Very uncomfortable, but they worked. As secretary of The Amphibians, (Howitt) wrote to the Dunlop Rubber Company in February 1949, as they had made the naval frogmen's fins during the war. Incredibly, they replied that they could see no commercial market for swim fins in peacetime. This response reflected the virtual non-existence of sport diving in the UK at that time." Seven military, national and international standards relating to swimfins are known to exist: US military standard MIL-S-82258:1965;
USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
and
CIS Cis or cis- may refer to: Places * Cis, Trentino, in Italy * In Poland: ** Cis, Świętokrzyskie Voivodeship, south-central ** Cis, Warmian-Masurian Voivodeship, north Math, science and biology * cis (mathematics) (cis(''θ'')), a trigonome ...
standard
GOST GOST (russian: ГОСТ) refers to a set of international technical standards maintained by the ''Euro-Asian Council for Standardization, Metrology and Certification (EASC)'', a regional standards organization operating under the auspices of th ...
22469—77 (Active);
German standard German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
DIN 7876:1980; Polish Industry Standard BN-82/8444-17.02. (Active). Austrian standard ÖNORM S 4224:1988; Malaysian standards MS 974:1985; MS 974:2002 (Active); and
European standard European Standards (abbreviated EN, from the German name ("European Norm")) are technical standards which have been ratified by one of the three European standards organizations: European Committee for Standardization (CEN), European Committee for ...
EN 16804:2015 (Active).


Types

Types of fins have evolved to address the requirements of each community using them. Recreational snorkellers generally use lightweight flexible fins. Free divers favour extremely long fins for efficiency of energy use.
Scuba divers This is a list of underwater divers whose exploits have made them notable. Underwater divers are people who take part in underwater diving activities – Underwater diving is practiced as part of an occupation, or for recreation, where t ...
need large wide fins to overcome the water resistance caused by their
diving equipment Diving equipment is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found ...
, and short enough to allow acceptable maneuvering. Ocean swimmers, bodysurfers, and
lifeguard A lifeguard is a rescuer who supervises the safety and rescue of swimmers, surfers, and other water sports participants such as in a swimming pool, water park, beach, spa, river and lake. Lifeguards are trained in swimming and CPR/ AED first a ...
s favour smaller designs that stay on their feet when moving through large surf and that make walking on the beach less awkward. Participants in the sports of
underwater hockey Underwater hockey (UWH), (also known as Octopush in the United Kingdom) is a globally played limited-contact sport in which two teams compete to manoeuvre a puck across the bottom of a swimming pool into the opposing team's goal by propelling ...
or
underwater rugby Underwater rugby (UWR) is an underwater team sport. During a match two teams try to score a negatively buoyant ball (filled with saltwater) into the opponents’ goal at the bottom of a swimming pool. It originated from within the physical f ...
use either full-foot or open-heel fins, and the chosen fin style is usually a compromise in performance between straight-line power and turning flexibility -
carbon fibre Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
blades are popular at higher levels of competition, but the over-riding requirement is that the fins must not have sharp or unprotected edges or points, nor buckles, which could injure other competitors. Structurally, a swimfin comprises a blade for propulsion and a means of attaching the blade to the wearer's foot.


Fins vs monofins

The vast majority of fins come as a pair, one fin is worn on each foot. This arrangement is also called bifins, to distinguish it from monofins. A
monofin A monofin is a type of swimfin typically used in underwater sports such as finswimming, free-diving and underwater orienteering. It consists of a single or linked control surface (fluid dynamics), surfaces attached to both of the diver's feet, ...
is typically used in
finswimming Finswimming is an underwater sport consisting of four techniques involving swimming with the use of fins either on the water's surface using a snorkel with either monofins or bifins or underwater with monofin either by holding one's breath or ...
and
free-diving Freediving, free-diving, free diving, breath-hold diving, or skin diving is a form of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear. Besides the limits of breath-h ...
and it consists of a single fin blade attached to twin foot pockets for both the diver's feet. Monofins and long bifin blades can be made of
glass fibre Glass fiber ( or glass fibre) is a material consisting of numerous extremely fine fibers of glass. Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the inventio ...
or
carbon fibre Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
composites. The diver's
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
power and swimming style, and the type of activity the fins are used for, determine the choice of size, stiffness, and materials.


Full-foot vs open-heel

Full-foot or closed-heel fins fit like a shoe and are designed to be worn over bare feet or soft neoprene socks; they are sometimes called "slipper" fins. Most fins with complete foot coverage have toe openings for comfort and for ease of water drainage inside the foot pocket. If a larger size is chosen, however, full-foot fins can also be worn over thicker neoprene socks or thin-soled booties. They are commonly used for surface swimming, and come in non-adjustable sizes. Open-heel fins have a foot pocket with an open heel area, and the fin is held to the foot by springs or straps which are usually adjustable and so will fit a limited range of foot sizes. They can be worn over boots and are common in diving, in particular where a diver has to walk into the water from a shore and requires foot protection. Some manufacturers produce fins with the same blade architecture but a choice of heel type.


Paddle vs split

Paddle fins have simple plastic, composite, or rubber blades that work as extensions of the feet while kicking. Some paddle fins have channels and grooves claimed to improve power and efficiency though it has been shown that the desired effect does not usually occur. Relatively stiff 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. Stiff paddle fins are required for certain types of kicks - such as
back kick A kick is a physical strike using the leg, in unison usually with an area of the knee or lower using the foot, heel, tibia (shin), ball of the foot, blade of the foot, toes or knee (the latter is also known as a knee strike). This type of atta ...
s and
helicopter turn Finning techniques are the skills and methods used by swimmers and underwater divers to propel themselves through the water and to maneuver when wearing swimfins. There are several styles used for propulsion, some of which are more suited to part ...
s - performed by scuba divers trained in
cave diving Cave-diving is underwater diving in water-filled caves. It may be done as an extreme sport, a way of exploring flooded caves for scientific investigation, or for the search for and recovery of divers or, as in the 2018 Thai cave rescue, other ...
and
wreck diving Wreck diving is recreational diving where the wreckage of ships, aircraft and other artificial structures are explored. Although most wreck dive sites are at shipwrecks, there is an increasing trend to scuttle retired ships to create artificia ...
to avoid stirring up sediment. Some swimfins have a split along the centreline of the blade. The manufacturers claim that split fins operate similarly to a
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
, by creating
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...
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.


Paddle variations


Vented

Vented fins were first designed in 1964 by
Georges Beuchat Georges Beuchat (11 February 1910 – 20 October 1991) was a French inventor, underwater diver, businessman and emblematic pioneer of underwater activities and founder of Beuchat. Throughout his lifetime, Beuchat never ceased developing produ ...
and commercialised as Jetfins. The Jetfin
tradename A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name w ...
and design were sold to
Scubapro Johnson Outdoors Inc. () produces outdoor recreational products such as watercraft, diving equipment, camping gear, and outdoor clothing. It has operations in 24 locations worldwide, employs 1,400 people and reports sales of more than $315 million ...
in the 1970s. 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. The study is only partially significant because it only considers the
flutter kick The flutter kick is a kicking movement used in both swimming and calisthenics. Swimming In swimming strokes such as the front crawl or backstroke, the primary purpose of the flutter kick is not propulsion but keeping the legs up and in the shad ...
, whereas the jetfin is mostly used with
frog kick Finning techniques are the skills and methods used by swimmers and underwater divers to propel themselves through the water and to maneuver when wearing swimfins. There are several styles used for propulsion, some of which are more suited to part ...
in the
technical diving Technical diving (also referred to as tec diving or tech diving) is scuba diving that exceeds the agency-specified limits of recreational diving Recreational diving or sport diving is diving for the purpose of leisure and enjoyment, usually ...
community. There is a risk of objects snagging in the vents.


Freediving

These are very similar to paddle fins, except they are far longer, and designed to work with slow stiff-legged kicks that are claimed to conserve oxygen and 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 fin blades are commonly made of plastic, but are also often made from composite materials using
fibreglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
or
carbon fibre Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
reinforcement. The composite blades are more resilient and absorb less energy when flexing, but are relatively fragile and more easily damaged.


Swimming training

The value of fins as an active aid in the teaching, learning and practice of swimming has long been recognised. In the US, as early as 1947, they were used experimentally to build the confidence of reluctant beginners in swimming, while a 1950
YMCA YMCA, sometimes regionally called the Y, is a worldwide youth organization based in Geneva, Switzerland, with more than 64 million beneficiaries in 120 countries. It was founded on 6 June 1844 by George Williams in London, originally ...
lifesaving and water safety manual reminded swimming instructors how "flippers can be used to great advantage for treading water, surface diving, towing, underwater searching and supporting a tired swimmer". In 1967, research was conducted on fin use in teaching the crawl stroke. During the 1970s, the so-called "flipper-float" method came into vogue in Europe with the aim of helping beginners learn to swim faster and more safely, while the deployment of fins to assist competitive swimmers in building sprint swimming speed skills also came under scrutiny. By 1990, ready-made short-bladed fins such as Marty Hull's "Zoomers" and cut-down longer-bladed fins became popular for lap swimming as swim workouts grew to be more nuanced and less regimented. Training fins, as they are now called, continue to be popular tools in an aquatic athlete's swimbag well into the new millennium, for recreational reasons as well as skill-building purposes.


Bodysurfing

Fins intended for bodyboarding or bodysurfing are usually relatively short with a stiff-blade, designed to produce a short burst of power and assist in catching a wave. Some versions have blades which are shorter at the inside edge. They are often made with an integral strap but an open heel, allowing sand to wash out more easily.


Attachment

Open heel fins are secured to the foot by a strap which passes around the back of the ankle. These are usually elastic and may be adjustable. Early fins used rubber straps connected to the fin by a wire buckle, and were not readily adjustable. Later versions incorporated swivels, buckles, quick release connectors and adjustable tension, but the increased complexity and decreased reliability, and tendency of the loose strap ends to hook on things triggered a return by some manufacturers and aftermarket accessory manufacturers to simpler systems. These include stainless steel spring straps and bungee straps, which once set up, are not adjustable, and which reduce the number of potential failure points and places where the fin can snag on obstructions like net, line and seaweed. Some heel straps have a loop for better grip with wet hands or gloves. Some fins designed for surf use have integral straps which can neither be replaced nor adjusted, but are simple and have no projections which can snag or scratch the swimmer's legs. They are much like full foot pocket fins without the back part of the sole, but do not trap as much sand when used in the surf. File:Swim_fin_strap_attacment_with_simple_rubber_strap_P5180292.jpg, Swim fin strap attachment with simple rubber strap and wire buckle File:Swim fin strap attachment plastic buckle and clip P5180294.JPG, Swim fin strap attachment with swivelling plastic buckle and clip File:Spring fin strap P5180295.JPG, Aftermarket stainless steel spring fin strap attached with long D-shackles for security File:Open heel fin with spring strap 2 P5180298.JPG, Open heel fin with stainless steel spring strap with rubber padding File:Cressi Master Frog fin with Scubapro bungee strap P5107573.JPG, Fin with bungee strap A full-foot swimming fin is designed to be secured on the foot by the elasticity of the fin's heelpiece. If this fin has a slightly oversized foot pocket, it may fall off when the user is swimming in choppy waters, but a pair of fin grips can help avert this mishap. ''Fixe-palmes'', fin retainers, or fin grips, were invented and patented in 1959 by the French diving equipment company
Beuchat Beuchat International, better known as Beuchat, is a company that designs, manufactures and markets underwater equipment. It was established in 1934 in Marseille, France, by Georges Beuchat, who descended from a Swiss watchmaking family. Geor ...
in
Marseilles Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Franc ...
. Widely copied during the 1970s, they are simple flat rings with three loops or straps made from thin high stretch rubber. These Y-shaped anchor straps are worn over the arch, the heel and the instep of each foot in order to secure strapless shoe-fitting (full foot) swim fins (see Figure 3). Although they are not designed to hold open-heel and strap models on, some swimmers and divers use them for this purpose. One loop is pulled over the foot above the ankle and the swim fin fitted to the foot. The second loop is pulled under the heel of the fin, leaving the remaining loop at the back of the heel. This procedure is illustrated in Figures 4–7. File:Fin Grips Figures 1-3.jpg, Figures 1-3: Fin grips before and after fitting. File:Fin Grips Figures 4-7.jpg, Figures 4-7: How fin grips are fitted on full-foot swimming fins. File:Fin grips.png, Two pairs of early fin grips: Beuchat Fixe-Palmes and Mares Fissapinne File:Technisub Ala Swimming Fins with Coloured Fin Grips.jpg, Underwater hockey fins with yellow and red pairs of fin grips. File:Yellow fin grip retaining a Technisub Ala swimming fin on the foot.jpg, A fin grip positioned to secure a full-foot swimming fin on the foot.


Use


Techniques

The use of swimfins for propulsion can be divided into propulsion and maneuvering aspects.


Propulsion

Three basic modes of propulsive finning can be distinguished: * Scissor or
flutter kick The flutter kick is a kicking movement used in both swimming and calisthenics. Swimming In swimming strokes such as the front crawl or backstroke, the primary purpose of the flutter kick is not propulsion but keeping the legs up and in the shad ...
involves alternate motion of the fins parallel to the
sagittal plane The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divid ...
of the swimmer. As the one leg thrusts in the ventral direction in the power stroke, the other performs the return stroke, which provides some thrust, but is significantly less powerful in most cases as the ankle tends to feather the blade. The blade must bend during the power stroke to thrust water away from the diver and thereby provide propulsion along the centreline. Efficient propulsion requires a low drag attitude in the water, and thrust along the direction of movement. *
Frog kick Finning techniques are the skills and methods used by swimmers and underwater divers to propel themselves through the water and to maneuver when wearing swimfins. There are several styles used for propulsion, some of which are more suited to part ...
involves the simultaneous and laterally mirrored motion of both legs together, mostly parallel to the
frontal plane The coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes. Details The coronal plane is an example of a longitud ...
. The power stroke is provided by thrusting the fins distally and towards the centreline by extending hips, knees and ankles, while rotating the fins to maximise thrust. The recovery stroke pulls the feathered fins towards the centre of mass and apart by flexing the hips, knees and ankles. *
Dolphin kick The dolphin kick is a kicking movement used in swimming. It is frequently used as part of the butterfly stroke and in underwater kicking. See also * Fish kick The fish kick is a method of kicking while swimming, generally used underwater. It ...
uses both legs together in a parallel motion. The movements are similar to those of flutter kick, but both legs perform the power and recovery strokes together. There is more use of the back and abdominal muscles, and considerable power can be exerted, but this requires equivalent effort, and can be stressful on people with lower back problems. Dolphin kick can be used with all fin types, and is the only option available when using a monofin. Modified styles of flutter and frog kick can be used to reduce down-flow of water which can disturb silt and reduce visibility, and are used when finning close to silty surfaces, such as inside caves and wrecks, or near the bottom of quarries, dams, lakes and some harbours.


Maneuvering

Turning on the spot and reversing are possible with suitable fins and skills. * The
back kick A kick is a physical strike using the leg, in unison usually with an area of the knee or lower using the foot, heel, tibia (shin), ball of the foot, blade of the foot, toes or knee (the latter is also known as a knee strike). This type of atta ...
is used to provide thrust along the length of the body, but in the opposite direction to normal propulsion. Back kick reversing is considered maneuvering rather than propulsion as it is relatively very inefficient and only used when necessary. * A
helicopter turn Finning techniques are the skills and methods used by swimmers and underwater divers to propel themselves through the water and to maneuver when wearing swimfins. There are several styles used for propulsion, some of which are more suited to part ...
is the rotation of the horizontal swimmer around a vertical axis through the body, by paddling movements of one or both fins, using mostly lower leg and ankle movement. The use of a separate fin on each foot allows far more freedom of motion for manoeuvering, as they can be used independently, in parallel or in opposition to produce thrust in a wide variety of directions. Manoeuverability with a monofin is relatively restricted.


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 upper leg flexion with bent knees like riding a
bicycle A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bic ...
is inefficient and is a common fault with divers who have not learned properly how to fin swim. This leg action feels easier because it is actually producing less thrust. 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.


Power

The upper sustainable limit of a diver's fin-kick thrust force using a stationary-swimming ergometer was shown to be . The maximum thrust averaged over 20 seconds against a strain gauge has been measured as high as . Resistive respiratory muscle training improves and maintains endurance fin swimming performance in divers.


Ergonomics

Experimental work suggests that larger fin blades are more efficient in converting diver effort to thrust, and are more economical in breathing gas for similar propulsive effect. Larger fins were perceived to be less fatiguing than smaller fins.


See also

* * * * * * * * *


References


External links

* * Fins Fo
Laps Swimming
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