Dry suit facts for kids
A dry suit is a type of protective clothing worn by scuba divers who are swimming in very cold water, such as in the Arctic ocean or the North Atlantic ocean. A dry suit is similar to a wetsuit, in that it helps to insulate the diver's body from the cold of the ocean. However, a wetsuit lets water to touch the diver's body, but a dry suit is sealed so it does not allow water to touch the diver's body. This means that a dry suit offers more protection from the cold ocean water.
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The Pirelli dry suit was designed in the 1930s and used by Italian frogmen during World War II. It became available for recreational divers after the war and was patented in 1951 for Pirelli by Eugenio Wolk, listed as the inventor. This two piece suit was made from thin and elastic rubber, optionally bonded to a knit fabric reinforcement liner except at the sealing areas at the neck, wrists and waist.
British frogmen of World War II and for some time afterwards used a similar one or two piece rubberized knit fabric suit by Siebe Gorman. They produced the one-piece front-entry Sladen suit with integral rubber helmet, developed by the British Admiralty for use with manned torpedoes, and in the late 1950s also the Essjee two-piece swim suit, based on the Sladen suit. The Essjee suit consisted of a jacket with rubber hood and lightweight wrist cuffs, and trousers shod with moulded rubber soles. The two parts were sealed by rolling the overlapped rubber skirts of the jacket and trousers together and these were held in place by a separate rubber cummerbund. Soft sponge-rubber pads inside the hood covered the ears and allowed them to be equalised. There was space under the suit for plenty of woollen underclothes. The suit was available in proofed gabardine or rubberised stockinette, with the cloth on the outside and the rubber inside, to protect the rubber from sunlight while in use.
In 1945 the Spearfisherman Company, owned by Arthur Brown, of Huntington Beach, California was approached by the US Navy to produce a rubber suit. These were advertised in the first issue of the Skin Diver magazine in December 1951, as “seamless, one-piece, pure gum rubber, nude freedom frogman suits”. These were entered by a chute which was folded and clamped to seal, and were available as full length or shortie suits with integral hood. Later versions had a neck level entry chute and a nape valve to purge trapped air. The shortie version was also rebranded as Kellys 7-seas suit.
A seamless dipped latex two-piece suit by an unidentified manufacturer, apparently marketed exclusively for women. was catalogued by Palley's of California in the early 1950s. The suit was made in two sections, connected by a rolled overlap similar to the Pirelli suits, and were available in long or short leg versions and long or short sleeved versions, all with integral neck, and cuff or arm and thigh seals. A separate hood was also available, and optional boots for the long leg version.
Waterwear of Newport Beach, California, produced the natural gum-rubber Seal suit for US Divers from 1953 or earlier. Several versions were available, including one piece and two piece suits. The one piece suits were available with long or short legs and sleeves, and with front, neck or back entry. Neck entry suits were sealed by overlapping the neck opening and the hood over a grooved neck ring, and clamping with a large elastic O-ring. The two piece suit shirt and pants were also available separately and could be sealed together at the waist by a system similar to the neck entry suit.
By the mid-1950s, C.E. Heinke & Co. Ltd., an established manufacturer of Standard diving equipment, had diversified into recreational underwater swimming equipment, including the Delta dry suit, made from natural rubber on a stockinette base. The basic Delta was a two piece suit made up of a jacket with neck seal and trousers with ankle seals which could be worn over woolen undergarments. The full suit included integral hood and feet. The overlapped and rolled waist seal was held in place by a cummerbund.
In 1955, Healthways retailed Carib drysuits, made of 3-ply translucent gum rubber, and available in long and short versions. Entry was by a front chute with rubber band closure. The full version included an integral hood and covered the feet. In 1957, they added the Aqua King and Aqua Flite dry suits to their product range. The Aqua King suit was a full-length waist entry suit, comprising hood, long sleeved shirt, booted pants and waistline sealing ring, and was made of seamless latex rubber. All these suits were available in small medium and large sizes.
W.J. Voit Rubber Corporation of New York, Danville and Los Angeles mamufactured the one-piece front-entry VDS10 and two-piece waist-entry VDS11 full dry suits in two ply lightweight gum rubber with integral boots and hood. These were available completed or as kits for home assembly.
The UK-based Dunlop Rubber Company produced drysuits for military and commercial divers and the Dunlop Aquafort range for recreational use.
Bel-Aqua Water Sports Company of Los Angeles (later Aquala Sports Manufacturing Company) marketed dry suits designed and manufactured by Bill Barada from 1954 or earlier. These were front entry one-piece or waist entry two piece suits with optional hood in 3-ply rubber, with optional integral hood, intended to be worn over insulating underwear suited to the water temperature. The front entry was sealed by binding the entry chute with a length of surgical rubber, and waist entry was sealed by rolling the overlap over a rubber ring. Boots, cuff and collar were moulded rubber. These were available in small, medium or large and were also available in kit form.
So-Lo Marx Rubber Company produced Skooba-"totes" dry suits from the late 1950s. These two piece seamless rubber suits with "ring and rail" waist seal, reinforced feet and optional hood were available in several colours over the years including green, brown, yellow and red. Sizes ranged from extra small to extra large.
The Dolphin Manufacturing Company of California designed and manufactured rubber spearfishing suits in the 1950s. Trading as Dolphin Enterprises, it sold the original front-entry Dolphin suits in ready-made and kit forms, before launching a new design 2-ply pocket entry suit. The Dolphin suit was available in four sizes and at least three colours (green, kelp and sand) with a tie-off sealed front-entry chute, hood and moulded boots. The company appears to have changed its name again to “Penguin Suits” after moving to Long Beach, California with the pocket entry suit as its leading product. Penguin suits marketed the one piece P1 suit with pocket entry, and the two-piece P2 suit with waist entry and roll seal, in red, blue or black including seamless moulded boots with scuff soles and an optional hood.
Introduction of the watertight zipper and variable volume dry suit
Development of space-suits in the 1960s led to the pressure-tight zipper, first manufactured by B.F. Goodrich, and first used on a dry suit by Bev Morgan in 1956. The suit was in expanded neoprene and had an oral inflator and latex seals. This was followed by the Unisuit, by Poseidon Industri AB of Sweden, also in neoprene, and which included a low pressure inflator valve and exhaust valves. The zipper ran from mid-back to mid-chest via the crotch. This design became the industry standard for a while and use was widespread. Overpressure valves were installed in the ankles, wrists and neck of dry suits to remove excessive air introduced through the face mask to prevent discomfort created by squeeze, which also increased the insulation capacity of the undergarments. These were called constant volume dry suits. Also in Sweden, Stig Insulán and Jorn Stubdal developed a vulcanised rubber drysuit, and Insulán patented the semi-automatic variable volume drysuit exhaust valve in 1971 which combined with the low pressure inflator valve gave the diver precise and trouble-free buoyancy control, in the variable volume dry suit.
The essential components include a shell of watertight material, sufficiently flexible to allow the wearer to function adequately, seals where parts of the body pass through the suit while in use, and a method of sealing the access opening while the suit is worn. Insulation may be provided in part by the suit shell, but is usually largely provided by thermal insulation clothing worn under the suit, which relies to a large extent on trapped air for its insulating properties. An inflation valve with gas supply and dump valve are generally provided, but were not standard on early models.
The main part of the dry suit is a waterproof shell made from a membrane type material, foamed neoprene or a hybrid of both.
Membrane dry suits are made from thin materials which have little thermal insulation. They are commonly made of stockinette fabric coated with vulcanized rubber, laminated layers of nylon and butyl rubber known as Trilaminate or Cordura proofed with an inner layer of polyurethane. With the exception of the rubber-coated stockinette, membrane dry suits typically do not stretch, so they need to be made slightly over-sized and baggy to allow flexibility at the joints through the wearer's range of motion and to allow the hands and feet to pass through without difficulty. This makes membrane dry suits easy to put on and take off, provides a good range of motion for the wearer when correctly sized and sufficiently inflated, and makes them relatively comfortable to wear for long periods out of the water compared to a wetsuit or close-fitting neoprene dry suit, as the wearer does not have to pull against rubber elasticity to move or keep joints flexed.
To stay warm in a membrane suit, the wearer must wear an insulating undersuit, today typically made with polyester or other synthetic fiber batting. Polyester and other synthetics are preferred over natural materials, since synthetic materials have better insulating properties when damp or wet from sweat, seepage, or a leak.
Reasonable care must be taken not to puncture or tear membrane dry suits, because buoyancy and insulation depend entirely on the air space in the undersuit, (whereas a wetsuit normally allows water to enter, and retains its insulation despite it). The dry suit material offers essentially no buoyancy or insulation itself, so if the dry suit leaks or is torn, water can soak the undersuit, with a corresponding loss of buoyancy and insulation.
Membrane dry suits may also be made of a waterproof but breathable material like Gore-Tex to enable comfortable wear without excessive humidity and buildup of condensation. This function does not work underwater. Sailors and boaters who intend to stay out of the water may prefer this type of suit.
Neoprene is a type of synthetic rubber which can be foamed during manufacture to a high proportion of tiny enclosed gas bubbles, forming a buoyant and thermally-insulating material, called "foamed neoprene", "foam-neoprene" or "expanded neoprene". Wetsuits are made from this material as it is a good insulator, waterproof, and is flexible enough for comfortable wear. The neoprene alone is very flexible, but not very resistant to tearing, so it is skinned with a layer of knit fabric bonded to each side for strength and abrasion resistance. Foamed neoprene may be used for the shell of a drysuit, providing some insulation due to the gas within the material, as in a standard wetsuit. If torn or punctured, leading to flooding, a foam-neoprene suit retains the insulation and buoyancy of the gas bubbles, like a wet suit, which is proportional to the thickness of the foam, Although foamed-neoprene dry suits provide some insulation, thermal under-suits are usually worn in cold water.
Neoprene dry suits are generally not as easy to put on and remove as are membrane dry suits, largely due to a closer fit which is possible due to the inherent elasticity of the material, and partly due to greater weight. As with wet suits, their buoyancy and thermal protection decreases with depth as the air bubbles in the neoprene are compressed. The air or other gas in the dry fabric undergarments providing insulation under a dry suit is also compressed, but can be restored to an effective volume by inflating the drysuit at depth through an inflator valve, thus preventing "suit squeeze" and compacting of the air-filled undersuit. Foam-neoprene tends to shrink over the years as it loses gas from the foam and slowly becomes less flexible as it ages. An alternative is crushed or compressed foam neoprene, which is less susceptible to volume changes when under pressure. Crushed neoprene is foam neoprene which has been hydrostatically compressed so much that the gas bubbles have been mostly eliminated, this retains the elasticity of foamed neoprene which allows freedom of movement, but does not provide much insulation, and is functionally more like a membrane suit.
Some suits marketed as hybrid suits combine the features of both types, with a membrane top attached to a neoprene bottom near the waist. The neoprene part is usually configured as a sleeveless "farmer-john" that covers the torso as well. This style is often used for surface water sports, especially in very cold water. The tight fitting lower part lets the wearer kick while swimming, and the loose fitting top allows easy arm movement. The torso covering also provides additional self-rescue or survival time if the suit leaks. Other manufacturers such as "Waterproof", use the term to refer to a membrane suit with integral liner of a relatively compression resistant porous 3-dimensional mesh, which creates a thin but resilient air space between the suit shell and the diver.
Seals at the wrists and neck prevent water entering the suit by a close contact fit against the skin around the wrists and neck. The seals are not absolutely watertight, however, and the wearer may experience some seepage during use. The wearer will also get damp due to sweat and condensation. The seals are typically made from latex rubber or foam neoprene, but are also available in silicone rubber. Latex seals are supple but easily damaged and deteriorate with exposure to oils, oxygen, and other materials, so they must be replaced periodically, every two years or more often. Latex also causes an allergic reaction in some users. Neoprene seals last longer and are non-allergenic, but, being less elastic, let more water enter because they do not seal as effectively as latex seals to the contours of wrist and neck. They are also typically glued and sewn together to form a tube, and may leak along that seam.
A recent innovation is the silicone seal, which is claimed to be as supple as latex, more flexible, yet far more durable. These are now available as original equipment on some makes of dry suit. Silicone seals are hypoallergenic, but can not be glued to the suit, and must be attached using clip-on rings. The silicone seals are similar in mechanical strength to latex seals but do not deteriorate as rapidly from oxidation and chemical attack. They are initially relatively expensive, but can be replaced without tools by the user which reduces cost of replacement.
Modern dry suits have a watertight zipper for entry and exit. The original bronze-toothed version was developed by NASA to hold air inside space suits. This complex and special zipper is one of the most expensive parts of the suit. Heavy duty. medium and lightweight versions are made. A later design uses injection moulded plastic teeth, and these are lighter, more flexible and less costly. The zipper is commonly installed across the back of the shoulders, since this placement compromises overall flexibility the least — but this design normally means the wearer requires assistance to close and open the zipper. The other common zipper placement is diagonally across the torso, which allows self-donning. Other designs place the zipper straight down the middle of the back (early Poseidon Unisuit), Up one side of the front, around the back of the neck and partway back down the front (later model Poseidon Unisuit or on a wide tubular chest entry opening which is folded down and clipped round the waist after sealing the zip (some Typhoon suits). The waterproof-zipper is stiff, and cannot stretch at all, which can make it difficult for a user to get into and out of the suit. Dry suits may also be fitted with an extra waterproof "fly", "relief" or "convenience" zipper to let the user urinate when out of the water when the suit is worn for long periods.
Before truly watertight zippers were invented, other methods of keeping the suit waterproof at the entry point were used, with the most common being a long rubber entry tunnel which would be folded shut, then rolled together from the sides and finally folded and clamped with a metal clip. An early example was the Sladen suit, where the entry tunnel was at the front of the torso. The Louisiana-based dry suit company Aquala makes a "historical" diving suit of that kind. Another type of entry featured a rubber tunnel that protruded through a non-watertight zipper. The tunnel would be rolled shut and the zipper closed to hold the roll in place.
Use of dry suits can conveniently be divided into surface and underwater applications, as the construction of the suit may be optimized for either.
Dry suits are often worn for boating, especially sailing, and on personal water craft in the winter months. The primary uses are for protection from spray, and in case of accidental short-term immersion in cold water if the user falls overboard. These dry suits, which are only intended for temporary immersion, are less rugged than diving dry suits. They are usually made of a breathable membrane material to let sweat permeate, keeping the wearer dry and comfortable all day. Membrane type surface dry suits only keep the user dry, and have little thermal insulating properties. Most users will wear a thin thermal undersuit, or street clothes, for warmth; but wearing ordinary fabrics can be dangerous if the suit leaks in cold water because they will lose most of their insulating properties.
Dry suits are used for windsurfing, kitesurfing, kayaking, water skiing and other surface water sports where the user is frequently immersed in cold water. These suits are often made from very lightweight material for high flexibility. Membrane type suits are commonly used in the spring and autumn with moderate water temperatures, but Neoprene and hybrid dry suits for surface sports are preferred in cold water. These provide greater thermal protection in the event of a leak. The ability to swim for self-rescue in these types of suits is important to water sports users that do not use a boat. A neoprene bottom also is less likely to allow trapped air to collect in the legs, causing the wearer to tend to float head down in the water.
Crew members who must work on the decks of commercial ships wear a type of dry suit also known as an immersion survival work suit. Single engine aircraft ferry pilots flying between North America and Europe, and helicopter pilots that must fly over the open ocean, must wear a survival suit in the cockpit, so they can continue to fly the aircraft, then exit immediately if the aircraft is ditched in cold water after an engine failure. These suits are also used on shore when working on docks, bridges, or other areas where cold water immersion is a safety risk. They are usually a three-part system consisting of:
- A warm undersuit made of synthetic fabric designed to wick moisture from sweat generated by physical exertion away from the user’s skin.
- A dry suit made with a waterproof breathable membrane to let moisture permeate out of the suit.
- A durable outer shell, designed to protect the dry suit, and to carry tools and survival gear. The outer shell may also be equipped with an inflatable bladder to give the wearer additional flotation and freeboard when immersed.
Immersion survival suits are dry suits carried for use by ship and aircraft crew who will be immersed in cold water if the craft must be abandoned. Unlike immersion survival work suits, these are not intended to be worn all the time, and are only to be used in an emergency. Survival suits will typically be a one-piece design made of fire-retardant neoprene, optimized with quick donning features, and produced in high visibility colours with reflective tape patches.
Dry suits are also worn by rescue personnel who must enter, or may accidentally enter, cold water. Features of dry suits designed for rescue may be a hybrid of the immersion survival and work suits, since the wearer is not expected to be working in the suit for an extended time. They may also be optimized for a specific task such as ice rescue, or helicopter rescue swimmer.
Dry suits are typically used where the water temperature is below 15 °C (60 °F), and for extended immersion in water above 15 °C (60 °F), where discomfort would be experienced by a wet suit user. They are also used with integral boots, and gloves and sealed to the helmet for personal protection when working in and around hazardous liquids.
Dry suits for recreational diving are made in both membrane and neoprene, and primarily differ from surface dry suits in that they have inflation and deflation air valves to maintain neutral buoyancy, and may be slightly more durable.
Dry suits for commercial and military diving tend to be heavier and more durable than recreational diving dry suits because they will endure a harsh and abrasive environment, especially if being used for heavy labor such as underwater welding. A boiler suit may be worn over the dry suit for additional protection of the suit. Some commercial dry suits are rated for contaminated environment diving, and when combined with a suitably rated diving helmet can completely isolate and protect the diver from hazardous environments such as sewage pits and chemical storage tanks. These "hazmat suits" are most often made of vulcanized rubber laminated to a cloth liner, which is easier to decontaminate because of its slick surface, than other dry suit materials.
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Low pressure inflation hose with CEJN connector (right) used for some dry suits