A wetsuit is a protective garment used for watersports such as scuba diving, surfing, windsurfing, kitesurfing, and triathlon. A modern, warm-water wetsuit is mostly made from thin open-cell neoprene, which provides limited thermal protection for activities in cold water, but protects the wearer in warm water from sun exposure. Cold-water wetsuits are built differently, have seams which do not leak, and provide good protection from cold water (to about 45°F, or 8°C) for up to 60 minutes in shallow water (less than 10 meters or 33 feet).[2][4] A wetsuit is usually lined with a nylon fabric to strengthen it and make it easy to put on and take off. Some newer wetsuits, usually marketed as "superflex", contain spandex in addition to neoprene to allow the suit to stretch (the panels of a wetsuit of this type typically contain 15-20% spandex).[citation needed] This counteracts neoprene's tendency to shrink with age[5]; it also allows for some changes in the wearer's size without making the suit uncomfortable.
Wetsuits help to preserve body heat by trapping a layer of water against the skin; this water is consequently warmed by body heat and acts as an insulator. [6]Water conducts heat away from the body approximately 25 times more efficiently than air[7], so an unprotected individual can succumb to hypothermia even in warm water on a warm day. Wetsuits are made out of closed-cell, foam neoprene, a synthetic rubber that contains small bubbles of nitrogen gas when made for use as wetsuit material. Nitrogen gas has very low thermal conductivity, so it reduces heat from the body (or the water trapped between the body and the wetsuit) from being lost to the water outside of the wetsuit. Some wetsuits of late have even begun to incorporate Merino wool and titanium fibers to add warmth characteristics, while keeping the thickness of the suit to a minimum. A wetsuit must have a snug fit to work efficiently; too loose a fit will allow water to escape from between the suit and the body, taking the body's heat with it. Flexible seals at the suit cuffs aid in the water retention. Neoprene is very buoyant, helping swimmers to better stay afloat, and for this reason divers need to calculate extra weight values based on the thickness of their suit to achieve neutral buoyancy underwater. The suit loses buoyancy and thermal protection as the bubbles in the neoprene are compressed at depth.
Suit creator history
It is difficult to credit a single individual for the creation of the modern wetsuit. In 1951, UC Berkeley and subsequent UC San Diego SIO physicist Hugh Bradner, who is considered to be the original inventor[8] and "father of the modern wetsuit,"[8] had the insight that a thin layer of trapped water could act as an insulator.[8][9] He initially sent his ideas to Lauriston C. "Larry" Marshall. Marshall was involved in a U.S. Navy/National Research Council Panel on Underwater Swimmers.[10] However, it was Willard Bascome, an engineer at the Scripps Institution of Oceanography in La Jolla, California, who suggested neoprene as a feasible material to Bradner.[9] However, Bradner and Bascome were not overly interested in profiting from their design and were unable to successfully market a version to the public.[9] They attempted to patent their neoprene wetsuit design, but their application was rejected because the design was viewed as too similar to a flight suit.[9] The United States Navy also turned down Bradner's and Bascome's offer to supply its swimmers and frogmen with the new wetsuits due to concerns that the noeprene component of the suits may make it easier for naval divers to be detected by underwater sonar.[9] The first written documentation of Bradner's invention was in a letter dated June 21, 1951. [10]
Bob and Bill Meistrell, from Manhattan Beach, California, also started experimenting with neoprene around 1953. They started a company which would later be named Body Glove.
Traditionally, most say it was Jack O'Neill who invented the wetsuit and started using neoprene, which he found lining the floor of an airliner. However, this is disputed by some aviation experts because neoprene and other rubbers are not fire retardant; therefore, they would not be found on any passenger aircraft. More importantly, it was not Jack, but his wife Bridget working with his brother, Robert who created the first designs for the company they later founded. Robert and Jack O'Neill went on to found the successful wetsuit manufacturing company called O'Neill in Pleasure Point, Santa Cruz, California with the motto "It's Always Summer on the Inside".
Neoprene was not the only material used in early wetsuits, particularly in Europe. The French-made Pêche-Sport Suit and the UK-made Siebe Gorman Swimsuit were both made out of sponge rubber. The Heinke Dolphin Suit of the same period, also made in England, came in a green male and a white female version, both manufactured from natural rubber lined with stockinet.
Suit design history
Originally, wetsuits were made only with raw sheets of foam-rubber neoprene that did not have any backing material. This type of suit required extra caution while pulling it on because the raw foam-rubber by itself is both fragile and sticky against bare skin. Stretching and pulling excessively easily caused these suits to be torn in half. This was somewhat remedied by thoroughly powdering the suit and the diver's body with talc to help the rubber slide on more easily.
Backing materials first arrived in the form of nylon sheeting applied to one side of the neoprene. This allowed a swimmer to pull on the suit relatively easily since the tough nylon took most of the strain of pulling on the suit, but the suit still had the black sheet rubber exposed on the outside and the nylon was very stiff and rigid, limiting flexibility. A small strip reversed with the rubber against the skin could help provide a sealing surface to keep water out around the neck, wrists, and ankles.
In the early 1960s, the British Dunlop Sports Company brought out its yellow Aquafort neoprene wetsuit, whose high visibility was designed to improve diver safety. However, the line was discontinued after a short while and wetsuits reverted to their black uniformity. The colorful wetsuits seen today first arrived in the 1970s when double-backed neoprene was developed. Now the foam-rubber was sandwiched between two protective fabric outer layers, greatly increasing the tear-resistance of the material. An external layer also meant that decorative colors, logos, and patterns could be made with panels and strips sewn into various shapes. This growth from bare flat black rubber to full color took off in the 1980s with brilliant fluorescent colors common on many suits.
Suit assembly history
The first suits used traditional sewing methods to simply overlap two strips of rubber and sew them together. In a rubber wetsuit this does not work well for a number of reasons, the main one being that punching holes straight through both layers of foam for the thread opens up passages for water to flow in and out of the suit. The second problem is that the stretching of the foam tended to enlarge the needle holes when the suit was worn. This meant that a wetsuit could be very cold all along the seams of the suit. And although the sewn edge did hold the two pieces together, it could also act as a perforated tear edge, making the suit easier to tear along the seams when putting it on and taking it off.
When nylon-backed neoprene appeared, the problem of the needle weakening the foam was solved, but still the needle holes leaked water along the seams.
Seam taping
To deal with all these early sewing problems, taping of seams was developed. The tape is a strong nylon cloth with a very thin but solid waterproof rubber backing. The tape is applied across the seam and bonded either with a chemical solvent or with a hot rolling heat-sealer to melt the tape into the neoprene.
With this technology, the suit could be sewn and then taped, and the tape would cover the sewing holes as well as providing some extra strength to prevent tearing along the needle holes.
When colorful double-backed designer suits started appearing, taping moved primarily to the inside of the suit because the tape was usually very wide, jagged, black, and ugly, and was hidden within the suit and out of sight.
Many 1960's and 1970's wetsuits were black with visible yellow seam taping. The yellow made the divers more easily seen in dark low-visibility water. To avoid this problem O'Neill fabricators developed a seam-tape which combined a thin nylon layer with a polyester hemming tape. Applied over the interior of the glued & sewn seam , then anneal bonded with a hand held teflon heating iron produced a seam that was both securely sealed and much stronger.
Seam gluing
Another alternative to sewing was to glue the edges of the suit together. This created a smooth, flat surface that did not necessarily need taping, but unfortunately raw foam glued to foam is not a strong bond and still prone to tearing.
Most early wetsuits were fabricated completely by hand, which could lead to sizing errors in the cutting of the foam sheeting. If the cut edges did not align correctly or the gluing was not done well, there might still be water leakage along the seam.
Initially suits could be found as being sewn only, glued only, taped only, then also sewn and taped, or glued and taped, or perhaps all three.
The blindstitch revolution
Sometime after nylon-backed neoprene appeared, the blind stitch method was developed. A blindstitch sewing machine uses a very unusual curved needle, which is designed to not go all the way through the neoprene but just shallowly dip in behind the fabric backing.
The curved needle allows the fabric backing to be sewn together without punching a hole completely through the neoprene, and thereby eliminating the water-leakage holes along the seam. Blindstitch seams also lay flat, butting up the edge of one sheet against another, allowing the material to lay flatter and closer to the skin. For these reasons blindstitching rapidly became the primary method of sewing wetsuits together, with other methods now used mainly for decorative or stylistic purposes.
Further advances in suit design
Highly elastic fabrics such as lycra and spandex have mostly replaced raw nylon backing, since the nylon by itself cannot be stretched and makes the neoprene very stiff. Incorporating lycra into the backing permits a large amount of stretching that does not damage the suit, and allowed suits to become closer fitting.
After the development of double-backed neoprene, singled-backed neoprene still had its uses for various specific purposes. For example a thin strip of single-backed wrapped around the leg, neck, and wrist openings of the suit creates a sticky rubber seal that greatly reduces the flushing of water in and out of the suit as the person's body moves. But since the strip is very narrow, it does not drag on the skin of the wearer and thus makes the suit easy to put on and remove.
As wetsuit manufacturers continued to design suits, they found ways that the materials could be further optimized and customized. The O'Neill Animal Skin created in 1974 by then Director of Marketing , E.J. Armstrong, was one of the first designs combining a turtle-neck based on the popular Sealsuit with a flexible lightweight YKK horizontal zipper across the back shoulders similar in concept to the inflatable watertight Supersuit ( developed by Jack O'Neill in the late 1960's ). The Animal Skin eventually evolved molded rubber patterns bonded onto the exterior of the neoprene sheeting ( a technique E.J. Armstrong perfected for application of the moulded raised rubber Supersuit logo to replace the standard flat decals ). This has been carried on as stylized reinforcing pads of rubber on the knees and elbows to protect the suit from wear, and allows logos to be directly bonded onto raw sheet rubber. Additionally, the Animal Skin's looser fit allowed for the use of a supplemental vest in extreme conditions.
In recent years, manufacturers have experimented by combining various materials with neoprene to lend additional warmth or flexibility to their suits. These include, but are not limited to, spandex, wool, and titanium fibers.
Precision computer-controlled cutting and assembly methods, such as water-jet cutting, have allowed ever greater levels of seam precision, permitting designers to use many small individual strips of different colors while still keeping the suit free of bulging and ripples from improper cutting and sewing.
The return of single-backed neoprene
As wetsuits continued to evolve, their use was explored in other sports such as open-water swimming and triathlons. Although double-backed neoprene is strong, the cloth backing is rough and creates a large amount of drag in the water, slowing down the swimmer. A single-backed suit meanwhile has a very smooth, slick exterior permitting water to slide easily over the bare neoprene. With the advances of elastic lycra backings and blindstitching, single-backed neoprene suits could now be made that outperformed the early cousins from the 1970s. Other developments in single-backed wetsuits include the suits designed for free-diving and spearfishing. Single lined neoprene is more flexible than double lined. To achieve flexibility and low bulk for a given warmth of suit, they are unlined inside, and the smooth surface of the neoprene is removed mechanically to reveal a rougher "open cell" surface which adheres closely to the skin and reduces flushing of the suit. The lined outer surface may be printed with camouflage patterns for spearfishing.
Some triathlon wetsuits go further, and use rubber-molding and texturing methods to roughen up the surface of the suit on the forearms, to increase forward drag and help pull the swimmer forwards through the water. Extremely thin 1 mm neoprene is also often used in the under-arm area, to decrease stretch resistance and reduce strain on the swimmer when they extend their arms out over their head.
Wetsuits used for caving are often single-backed with a textured surface known as "sharkskin" which is a thin layer where the neoprene is less expanded. This makes it more abrasion resistant for squeezing between rocks and doesn't get torn in the way that fabric does.
Types
A shorty wetsuit.
Wetsuits come in different thicknesses depending on the conditions for which it is intended. The thicker the suit, the warmer it will keep the wearer. Because wetsuits offer significant protection from jellyfish, coral and other hazards, many divers opt to wear a thin suit which provides minimal insulation (often called a "bodysuit") even when the water is warm enough to comfortably forego insulating garments. A thick suit is stiff, so mobility is restricted; at a certain thickness the suit would become impractical, which is why drysuits must be worn in particularly cold environments. A wetsuit is normally described in terms of its thickness. For instance, a wetsuit with a torso thickness of 5 mm and a limb thickness of 3 mm will be described as a "5/3". With new technologies the neoprene is getting more flexible. Modern 4/3 wetsuits, for instance, may feel as flexible as a 3/2 of only a few years ago. Some suits have extra layers added for key areas such as the lower back.
Different shapes of wetsuit are available, in order of coverage:
A sleeveless vest, covering only the torso, provides minimal coverage. Some include an attached hood. These are not intended to be worn alone, but rather as an extra layer over or under a longer wetsuit.
A jacket covers the torso and arms, with little to no coverage for the legs. Some jackets have short leg sleeves like a shorty, others feature leg holes similar to a women's swimsuit. A third style, the beavertail, which was quite popular until the 1980s, had a flap which closed over the crotch and attached at the front with a fastener.
A shorty or spring suit covers the torso and has short sleeves for the arms and legs. There are also forms of spring suits with long arms and short legs.
A long john or farmer john/jane (depending on the gender the suit is designed for) covers the torso and legs only; it resembles a bib-and-brace overall, hence the nickname.
A full suit or steamer covers the torso and the full length of the arms and legs.
Some suits are arranged in two parts; the jacket and long johns can be worn separately in mild conditions or worn together to provide two layers of insulation around the torso in cold conditions. Typically, cold water wetsuits have 12 to 15 mm of material around the torso and 6 to 8 mm for the extremities.
Usually they have no feet or hood, and the diver must wear separate booties and hood made from wetsuit material.
Using hoods: in the thermal balance of the human body, the heat loss over the head is at least 20% of the whole balance. Thus, for the sake of thermal protection of the diver, wearing a well-fitting hood is good practice, even at fairly moderate water temperatures.
A specialized kind of wetsuit, with a very smooth (and somewhat delicate) outer surface is used for long distance swimming and triathlon. These are designed to maximize the mobility of the limbs while providing both warmth and buoyancy.
Heated wetsuits also being tested and will soon be available on the market. These suits have special heating panels integrated in the back of the wetsuit. The power for heating comes from batteries also integrated into the wetsuit.
Controversy
In open water swimming events, the use of wetsuits is controversial, with many participants believing that wetsuits give some swimmers a competitive advantage (by increasing their buoyancy and hydrodynamic curve). Some open water swimmers, in fact, believe that wearing a wetsuit is contrary to the spirit of the sport, and that people who wear the suits should be the objects of derision.
Unlike triathlons, which allow swimmers to wear wetsuits when the water is below a certain temperature, most open water swim races either don't allow the use of wetsuits (usually defined as anything covering the body above the waist or below the knees), or put wetsuit-clad swimmers in a separate category and/or make them ineligible for race awards. This differs in locales and times of the year, where water temperatures are substantially below comfortable.
NOTE:
没有评论:
发表评论