A wetsuit is a garment worn to provide thermal protection while wet. It is usually made of foamed neoprene, and is worn by surfing, divers, windsurfers, canoeists, and others engaged in water sports and other activities in or on the water. Its purpose is to provide thermal insulation and protection from abrasion, ultraviolet exposure, and stings from marine organisms. It also contributes extra buoyancy. The insulation properties of neoprene foam depend mainly on bubbles of gas enclosed within the material, which reduce its ability to conduct heat. The bubbles also give the wetsuit a low density, providing buoyancy in water.
Hugh Bradner, a University of California, Berkeley, physicist, invented the modern wetsuit in 1952. Wetsuits became available in the mid-1950s and evolved as the relatively fragile foamed neoprene was first backed, and later sandwiched, with thin sheets of tougher material such as nylon or later spandex. Improvements in the way joints in the wetsuit were made by gluing, taping and blind-stitching, helped the suit to remain waterproof and reduce flushing, the replacement of water trapped between suit and body by cold water from the outside. Further improvements in the seals at the neck, wrists, ankles, and zippers produced a suit known as a "semi-dry".
Different types of wetsuit are made for different uses and for different temperatures. Suits range from a thin 2mm or less "shortie", covering just the torso, upper arm, and thighs, to thick 8mm semi-dry suit covering the torso, arms, and legs, usually complemented by neoprene boots, gloves and hood. The type of the suit depends upon the temperature of the water and the depth of the planned dive.
The difference between a wetsuit and a dry suit is that a wetsuit allows water to enter the suit, though good fit limits water circulation inside the suit, and between the inside and outside of the suit, while dry suits are designed to prevent water from entering, thus keeping the undergarments dry and preserving their insulating effectiveness. Wetsuits can give adequate protection in warm to moderately cold waters. Dry suits are typically more expensive and more complex to use, but can be used where protection from lower temperatures or Contamination water is needed.
Uncompressed foam neoprene has a typical thermal conductivity in the region of 0.054 Wm−1K−1, which produces about twice the heat loss of still air, or one-tenth the loss of water. However, at a depth of about of water, the thickness of a typical neoprene foam will be halved and its conductivity will be increased by about 50%, allowing heat to be lost at three times the rate at the surface. The grade of foam neoprene strongly affects insulating properties at depth, and over time. Softer, lighter, and more elastic grades contain a higher percentage of gas bubbles, and are comfortable and provide effective insulation at or near the surface where they retain much of their thickness. Areas that are significantly stretched lose thickness even before they are compressed at depth, which also reduces the insulation, and long periods under pressure and repeated compression and decompression of the neoprene foam will eventually lead to loss of volume, insulation, buoyancy and flexibility. Some bubbles will also rupture under stress and lose their gas, and the foam will start to absorb more water, further reducing insulation. Wetsuits for diving should be made from less compressible neoprene to keep their insulating qualities.
A wetsuit must have a snug fit to work efficiently when immersed; too loose a fit, particularly at the openings (wrists, ankles, neck and overlaps) will allow cold water from the outside to enter when the wearer moves. Flexible seals at the suit cuffs aid in preventing heat loss in this fashion. The elasticity of the foamed neoprene and surface textiles allow enough stretch for many people to effectively wear off-the-shelf sizes, but others have to have their suits custom fitted to get a good fit that is not too tight for comfort and safety. Places where the suit bridges a hollow tend to change volume when the wearer bends that part of the body, and the change in volume of the space under the suit works as a pump to push warm water out of the suit and suck cold water in on the opposite movement.
Measurements of volume change of neoprene foam used for wetsuits under hydrostatic compression shows that about 30% of the volume, and therefore 30% of surface buoyancy, is lost in about the first 10 m, another 30% by about 60 m, and the volume appears to stabilize at about 65% loss by about 100 m. The total buoyancy loss of a wetsuit is proportional to the initial uncompressed volume. An average person has a surface area of about 2 m2, so the uncompressed volume of a full one piece 6 mm thick wetsuit will be in the order of 1.75 x 0.006 = 0.0105 m3, or roughly 10 liters. The mass will depend on the specific formulation of the foam, but will probably be in the order of 4 kg, for a net buoyancy of about 6 kg at the surface. Depending on the overall buoyancy of the diver, this will generally require 6 kg of additional weight to bring the diver to neutral buoyancy to allow reasonably easy descent. The volume lost at 10 m is about 3 liters, or 3 kg of buoyancy, rising to about 6 kg buoyancy lost at about 60 m. This could nearly double for a large person wearing a farmer-john and jacket for cold water. This loss of buoyancy must be balanced by inflating the buoyancy compensator to maintain neutral buoyancy at depth.
There is also a buoyancy loss due to gas loss from the bubbles over time, and the neoprene also loses flexibility with time, and tends to stiffen and shrink. This tendency is exacerbated by frequent use, deep dives, and exposure to sunlight. The "compressed neoprene" and "crushed neoprene" used for hot water suits and , is permanently reduced in volume by intentional hydrostatic compression during the manufacturing process, specifically to reduce buoyancy change with depth, at the cost of reducing insulation.
Bradner and Bascom were not overly interested in profiting from their design and were unable to successfully market a version to the public. 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. The United States Navy also turned down Bradner's and Bascom's offer to supply its swimmers and frogmen with the new wetsuits due to concerns that the gas in the neoprene component of the suits might make it easier for naval divers to be detected by underwater sonar. The first written documentation of Bradner's invention was in a letter to Marshall, dated June 21, 1951.
Jack O'Neill started using closed-cell neoprene foam which he claimed was shown to him by his bodysurfing friend, Harry Hind, who knew of it as an insulating material in his laboratory work. After experimenting with the material and finding it superior to other insulating foams, O'Neill founded the successful wetsuit manufacturing company called O'Neill in a San Francisco garage in 1952, later relocating to Santa Cruz, California in 1959 with the motto "It's Always Summer on the Inside". 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.
Neoprene was not the only material used in early wetsuits, particularly in Europe and Australia. The Pêche-Sport "isothermic" suit invented by Georges Beuchat in 1953 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. As early as July 1951, spearfishing in Australia were experimenting with a natural rubber wetsuit "of a 'wrap on' variety, which does not set out to be 100% waterproof (but it is claimed that) the leakage of water through it is so slow that body warmth under it is maintained for hours." By May 1953, the Bondi underwater equipment manufacturer Undersee Products was already distributing this sleeveless shirt design commercially to Australian sporting goods stores, where it was described thus: "Made from heavy sheet rubber, the Sealskin suit is most effective when worn over a football jersey. When jersey becomes wet, rubber holds it firmly against body and thus warmth is generated. Water circulation automatically stops and body warmth builds up in moisture-laden jersey. The Seaskin suit provides both underwater insulation and above-water wind protection".
Backing materials first arrived in the form of nylon knit cloth applied to one side of the neoprene. This allowed a swimmer to pull on the suit relatively easily since the nylon took most of the stress of pulling on the suit, and there was less friction between the nylon and skin, but the suit still had the bare foam exposed on the outside and the nylon was relatively stiff, limiting flexibility. A small strip of neoprene reversed with the rubber against the skin could help provide a sealing surface to keep water out around the neck, wrists, and ankles.
In 1960, the British Dunlop Sports Company brought out its yellow Aquafort neoprene wetsuit, whose high visibility was intended to improve diver safety. However, the line was discontinued after a short while and wetsuits reverted to their black uniformity. The colorful wetsuits seen more recently first arrived in the 1970s when double-backed neoprene was developed. In this material the foam-rubber is sandwiched between two protective fabric outer layers, greatly increasing the tear-resistance. An external layer also meant that decorative colors, logos, and patterns could be made with panels and strips sewn into various shapes. This change from bare flat black rubber to full color took off in the 1980s with brilliant fluorescent colors common on many suits.
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.
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 1960s and 1970s wetsuits were black with visible yellow seam taping. The yellow made the divers more easily seen in dark low-visibility water. To prevent needle holes from leaking, 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.
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 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 stitching methods now used mainly for decorative or Fashion purposes.
After the development of double-backed neoprene, singled-backed neoprene still has its uses. A narrow edge strip of smooth surfaced single-backed neoprene wrapped around the leg, neck, and wrist openings of the suit creates a more effective seal against the skin than the knit fabric backing, that reduces the flushing of water in and out of the suit at these places as the person moves. Since the strip is narrow, it does not drag on the skin of the wearer much and the lining makes the suit easy to put on and remove. The strip can also be fitted with the smooth side out and folded under to form a seal with a small length of smooth surface against the skin and slightly greater contact pressure. This type of seal can also be used on neoprene dry suits as it is sufficiently watertight when properly designed.
In the early 1970s Gul Wetsuits pioneered the one-piece wetsuit named the 'steamer' because of the visible condensed water vapour given off from the suit when taken off, allowing heat and water held inside to escape. One-piece wetsuits are still sometimes referred to as 'steamers'.
As wetsuit manufacturers continued to develop suit designs, 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 1960s). The "Animal Skin" eventually evolved molded rubber patterns bonded onto the exterior of the neoprene sheeting (a technique E.J. Armstrong developed 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.
More recently, manufacturers have experimented by combining various materials with neoprene for additional warmth or flexibility of their suits. These include, but are not limited to, spandex, and wool.
Companies, such as Patagonia, have been recycling the material made from older worn wetsuits and remodeling them into a low-carbon wetsuit.
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 misaligned sewing. Further innovations in CAD (Computer Aided Design) technology allow precision cutting for custom-fit wetsuits.
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 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.
Another reason to eliminate the external textile backing is to reduce water retention which can increase evaporative cooling and wind chill in suits used mainly out of the water.
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, two-piece cold water wetsuits have 10 to 14 mm combined thickness of neoprene over the torso and 5 to 7 mm single thickness over the limbs.
A wetsuit with a very smooth and somewhat delicate outer surface known as smoothskin, which is the original outer surface of the foamed neoprene block from which the sheets are cut, is used for long-distance swimming, triathlon, competitive apnoea, and bluewater spearfishing. These are designed to maximize the mobility of the limbs while providing both warmth and buoyancy, but the surface is delicate and easily damaged. The slick surface also dries quickly and is least affected by wind chill when out of the water.
Both smoothskin and fabric lined surfaces can be printed to produce colour patterns such as camouflage designs, which may give spearfishermen and combat divers an advantage.
Wetsuits are made in several standard adult sizes and for children. Custom fitted suits are produced by many manufacturers to provide a better fit for people for whom a well fitting off-the shelf suit is not available.
Wetsuits heated by a flow of hot water piped from the surface are standard equipment for commercial diving in cold water, particularly where the heat loss from the diver is increased by use of helium based breathing gases. Hot water suits are a loose fit as there is a constant supply of heated water piped into the suit which must escape to allow even flow distribution. Flushing with cold water is prevented by the constant outflow of heating water.
For cold water use, thicker mittens with a single space for the middle, ring and fifth fingers are available and can provide more warmth at the cost of reducing dexterity.
Development of suit design
Improvements in suit assembly
Seam taping
Seam gluing
Blindstitching
Further advances in suit design
Return of single-backed neoprene
Types
Configurations
Thickness
Surface finish
Wetsuit lining
Closures
Sizing and fit
Semi-dry suits
Heated suits
Accessories
Hoods
Boots
Thermal protection
Foot protection
For scuba diving
For surfing
For kayaking
Gloves
See also
Notes
External links
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