subject: Swimfin - Bellyband Manufacturer - Medical Crutch Manufacturer [print this page] History History
Early inventors, including Leonardo da Vinci and Giovanni Alfonso Borelli, toyed with the concept of swimfins.
Benjamin Franklin made a pair of early swimfins when he was a young boy living in Boston, Massachusetts near the Charles River; they were two thin pieces of wood, about the shape of an art palette, which allowed him to move faster than he usually did in the water.
Louis de Corlieu in France and Owen Churchill in the United States, working independently of each other, were the first to make swimfins a practical reality. Churchill's design caught the attention of the United States Navy, which issued it to their Underwater Demolition Teams in the early 1940s. Fins of this design can still be found in just about any sporting goods store or surf shop.
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 to plimsolls), until Oscar Gugen began importing swimfins and swimming goggles from France.
In 1946 Lillywhites imported about 1100 pairs of swimfins; they all sold in under 3 months.
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 rubber stretched across a frame of stiff rubber tube.
Types
Cressi-sub vented paddle fin
Beuchat Closed-heel Jetfins
Beuchat Open-heel adjustable Jetfins
A freediver using a monofin
Types of fins have evolved to address the unique requirements of each community using them. Scuba divers, in particular, need large wide fins to overcome the water resistance caused by their diving equipment; snorkelers need lightweight flexible fins; ocean swimmers, bodysurfers, and lifeguards 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. 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.
Common types
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 convoluted 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 Beuchat and commercialised as Jetfins. The Jetfin tradename and design were sold to Scubapro in the 1970. 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.[citation needed] 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 propeller, by creating lift 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 Predergast et al called this into question by showing that a 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 fiber.
Monofins
A monofin is typically used in finswimming and free-diving. It consists of a single surface attached to footpockets for both the free-diver's feet. Monofins can be made of glass fibre or carbon fibre. The diver's muscle 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 cramps and reduces foot strain.
Flipfins
Flipfins are USA-made type of 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.
Breast stroke fins
Breast stroke fins are optimized for use with the breaststroke.
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 bicycle 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 was shown to be 64newtons (14lbf). The maximum thrust averaged over 20seconds against a strain gauge has been measured as high as 192newtons (43lbf). Resistive respiratory muscle training improves and maintains endurance fin swimming performance in divers.
See also
Human swimming
PowerSwim, a device somewhat like two pairs of long thin airplane wings fastened to a scuba diver's hips and legs
Diving equipment
Scuba equipment
Finswimming
References
^ a b c d e Pendergast, DR; Mollendorf, J; Logue, C; Samimy, S (2003). "Evaluation of fins used in underwater swimming". Undersea Hyperbaric Medicine (Undersea and Hyperbaric Medical Society) 30 (1): 5773. PMID 12841609. http://archive.rubicon-foundation.org/3936. Retrieved 11 February 2010.
^ Pendergast D, Mollendorf J, Zamparo P, Termin A, Bushnell D, Paschke D (2005). "The influence of drag on human locomotion in water". Undersea Hyperb Med 32 (1): 4557. PMID 15796314. http://archive.rubicon-foundation.org/4037. Retrieved 2008-08-25.
^ a b c Pendergast DR, Tedesco M, Nawrocki DM, Fisher NM (May 1996). "Energetics of underwater swimming with SCUBA". Med Sci Sports Exerc 28 (5): 57380. doi:10.1097/00005768-199605000-00006. PMID 9148086. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0195-9131&volume=28&issue=5&spage=573. Retrieved 2008-08-25.
^ a b Davis, RH (1955). Deep Diving and Submarine Operations (6th ed.). Tolworth, Surbiton, Surrey: Siebe Gorman & Company Ltd.
^ "Benjamin Franklin (USA) 1968 Honor Contributor". International Swimming Hall of Fame. http://www.ishof.org/honorees/68/68bfranklin.html. Retrieved 2009-05-29.
^ Marx, Robert (1990). "11" (in English). The History Of Underwater Exploration. Into The Deep (2nd ed.). United States: Courier Dover Publications. pp.198. ISBN 0486264874. http://books.google.com/books?id=oiWFhoRzPBQC&pg=PA127&lpg=PA127&dq=%22owen+churchill%22+swim+fin&source=web&ots=otq6RINAFX&sig=CLwf2XH8oZecXHMZjAXRnLiMFJM&hl=en#PPA127,M1. Retrieved 2009-05-29.
^ McMurray RG (1977). "Competitive efficiencies of conventional and super-swinfin designs.". Hum Factors 19: 495501.
^ Zamparo P, Pendergast DR, Termin A, Minetti AE (March 2006). "Economy and efficiency of swimming at the surface with fins of different size and stiffness". Eur. J. Appl. Physiol. 96 (4): 45970. doi:10.1007/s00421-005-0075-7. PMID 16341874.
^ Pendergast DR, Mollendorf J, Logue C, Samimy S (2003). "Underwater fin swimming in women with reference to fin selection". Undersea Hyperb Med 30 (1): 7585. PMID 12841610. http://archive.rubicon-foundation.org/3935. Retrieved 2008-08-25.
^ a b Apollo Sports USA. "Principles of Split Fin Operation". http://www.apollosportsusa.com/Products/Fins/Principles.htm. Retrieved 11 February 2010.
^ "Force Fin". http://www.forcefin.com/index.html. Retrieved 11 February 2010.
^ Evans, Robert B (14 July 1992). "Open-toed wide-blade swim fin". United States Patent Office. http://www.google.co.uk/patents?id=gW0qAAAAEBAJ&printsec=abstract. Retrieved 15 February 2010.
^ Lee, Marc (2009). "Swimming Fins on Legs". Shinfin Pty. http://shinfin.com/. Retrieved 11 February 2010.
^ "Flipfins". Omega Aquatics. 2008. http://www.flipfins.com/. Retrieved 30 December 2009.
^ Video of Flipfins in use entering from beach and underwater and climbing out onto a boat at YouTube
^ Brittain, Colin (2004). "Practical diver training". Let's Dive: Sub-Aqua Association Club Diver Manual (2nd ed.). Wigan, UK: Dive Print. p.44. ISBN 0-9532904-3-3. http://www.saa.org.uk/. Retrieved 11 February 2010.
^ Jablonski, J (2001). Doing it Right: The Fundamentals of Better Diving. Global Underwater Explorers. p.100. ISBN 0971326703.
^ Yamaguchi H, Shidara F, Naraki N, Mohri M (September 1995). "Maximum sustained fin-kick thrust in underwater swimming". Undersea Hyperb Med 22 (3): 2418. PMID 7580765. http://archive.rubicon-foundation.org/2219. Retrieved 2008-08-25.
^ Lindholm P, Wylegala J, Pendergast DR, Lundgren CE (2007). "Resistive respiratory muscle training improves and maintains endurance swimming performance in divers". Undersea Hyperb Med 34 (3): 16980. PMID 17672173. http://archive.rubicon-foundation.org/7342. Retrieved 2008-08-25.
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Equipment:
Diving suit Scuba set Rebreather Dive computer Diver propulsion vehicle Mask Fins Snorkel Buoyancy control device
Disciplines:
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Hazards:
Decompression sickness Nitrogen narcosis Oxygen toxicity Barotrauma Hyperbaric medicine Drowning Shallow water blackout Deep water blackout High pressure nervous syndrome Dysbaric osteonecrosis
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Competitive swimwear
Female suits:
Racerback Kneeskin Bodyskin
Male suits:
Swim briefs Jammers Square leg suits Legskin Kneeskin Bodyskin
Accessories:
Goggles Swim cap Nose Clip Ear Plugs
Training gear:
Training fins Pull buoy Hand Paddles Fistgloves Swimming board Swimming machine Inflatable armbands
Categories: Diving equipment | Sports footwearHidden categories: All articles with unsourced statements | Articles with unsourced statements from February 2010
