Diving suit
A diving suit or diving suit protects the body of a diver in the water against hypothermia . The first suits were made of leather and metal, later natural rubber and now mainly neoprene foam were used (" neoprene suit "). A basic distinction is made between wet suits ( wetsuit ), semi- dry suits and dry suits ( drysuit ). For better insulation from the cold, the suit can optionally be supplemented with diving gloves , booties and a hood.
history
In tropical and subtropical areas, the first pearl and sponge divers went about their work naked or only in loincloths . These waters are also very cool at greater depths and when you stay for a long time. Since most of the divers were slaves , little importance was attached to them.
Konrad Kyeser describes diving suits made of leather for military use around 1405. The lower water temperatures in the North and Baltic Seas, for example, made it essential to protect the body from heat loss. In the second half of the 17th century, for example, divers were lowered into the wreck of the Vasa in a diving bell in order to recover the cannons. These divers wore leather suits with little protection against the cold, so that they too were still very cold. Nevertheless, until the middle of the 19th century, leather and wool were the only available fabrics that offered freedom of movement and (albeit little) thermal protection, and these suits also provided the wearer with little protection from injuries. Otherwise, as before, they dived into swimwear.
With the invention of the vulcanization of rubber by Charles Goodyear in 1839 (patented in 1844), a robust waterproof material was available. This gradually gained acceptance. The insulating effect of the rubber itself was negligible, but since the diver in the suit remained largely dry, he could wear warming undergarments made of air-containing woolen textiles.
Neoprene (synthetic rubber) was invented in 1930. Until the 1940s, rubberized suits were used in particular by the first combat swimmers. As a material for diving suits, neoprene foam was introduced to the market in California by Bob and Bill Meistrell in 1954 with the company Barakuda.
For some years now, textile laminate (trilaminate) has also been used for drysuits.
Wet suit
The wet suit is usually made of neoprene or comparable materials with a thickness between 2.5 and 8 mm, sometimes with an inner lining made of terry cloth , nylon or another skin-friendly textile. It is cut so that it is skin-tight on the body. The material of the suit is waterproof, but when immersed, the water can penetrate the zips , the neck opening and the hand and foot cuffs and fill all the spaces between the body of the diver and the suit. With a wet suit, the water that has penetrated the suit can circulate through the movements of the wearer , which ensures heat exchange with the environment.
In a wet suit, the effectiveness of the thermal insulation depends not only on the thickness of the material, but also on the fit of the suit. The better the suit fits, the less the water can circulate inside and dissipate heat. An unlined suit with an inside made of open-cell neoprene fits the body better and can reduce circulation. Custom-made products are available from a few manufacturers.
It is almost always designed as an overall (usually with long sleeves and pant legs) and is intended to prevent areas of skin covered by the suit from coming into direct contact with water. In addition, the neoprene containing gas bubbles acts as a thermal insulator so that the body does not cool down. Small amounts of water penetrate the suit through the collar , arm and leg cuffs, and especially through the zipper. Therefore, wet suits are unsuitable for low water temperatures.
Wet suits come in different shapes:
- As a one-piece tropical suit for diving in warm waters with a neoprene thickness of 2.5 to 3 mm. The tropical suit usually has no hood and can have long or short sleeves and legs. Suits with short arms and legs are called shorty . In tropical waters, the suit is not only supposed to protect against hypothermia, but also serves as physical protection (for example against cnidarians ).
- as a one-piece with a neoprene thickness between 4 and 8 mm. This suit has long sleeves and legs and usually an attached hood. When diving in cooler waters, it can be supplemented with a neoprene vest , which keeps the diver's torso warm with an additional neoprene layer.
- as a two-piece , consisting of long, high-cut or bib shorts (called "Long John") and a long-sleeved jacket, usually with an attached hood - both with a material thickness between 5 and 8 mm. There are always two layers of neoprene on top of each other on the diver's torso, so this suit is particularly suitable for cooler waters.
The advantages of wetsuits are the relatively low acquisition costs and the versatile application possibilities in both tropical and cooler waters. The most important disadvantage is that even in well-fitting suits, water circulation can never be completely cut off. Wet suits are only conditionally suitable for cold water diving.
The neoprene strength of the suit has an impact on buoyancy , as thicker material creates more static buoyancy . This buoyancy has to be compensated with lead weights . To make matters worse, the neoprene itself is compressed by the water pressure increasing with depth, so that the buoyancy decreases with increasing ambient pressure - i.e. increasing water depth. Since the weight of the lead remains constant, the downforce increases with increasing depth, which has to be compensated for by a buoyancy compensator ( buoyancy compensator, jacket).
Wet suits are also worn as surf suits by surfers , kite surfers , windsurfers , water skiers and, if required, as swimsuits also by swimmers , triathletes and when jumping in the water also when skydiving . However, wet suits for diving are constructed in such a way that the neoprene in wet suits does not lose any significant thermal insulation properties, even under increased ambient pressure. This is not necessarily the case with wetsuits for surface water sports.
Semi-dry suit
The semi-dry suit is a one-piece wet suit made of neoprene with a thickness between 5 and 8 mm. On the sleeves, on the feet and on the face or neck it has single or double sealing cuffs made of neoprene, which reduce the exchange of water (circulation), as well as a water- or gas-tight zipper. The insulation is as accepted during normal wet suit from neoprene. The semi-dry suit fits closely to the body and cannot be filled with air like the dry suit for buoyancy control. The advantage of the semi-dry suit is the improved thermal insulation compared to the normal wet suit, which results from the lower water exchange and thus lower convection , which makes it better suited for cold water diving (up to ice diving ). The usually higher price is disadvantageous.
Hot water suit
The hot water suit (also known as a hot water suit in Switzerland ) is a wet suit that is used exclusively by professional divers who are supplied with a helmet diving device and with hoses and cables from the surface . An insulated hose leads the hot water from the surface to the diver. There the diver can regulate the flow of hot water with a valve , which he usually attaches to his hip, like a radiator . The hot water suit is usually a non-tight-fitting neoprene wet suit with hoses for distributing the hot water. The warm water is released into the environment through the open cuffs and legs.
Hot water suits are often used on very deep dives with trimix . The high proportion of helium contained in Trimix dissipates heat much more effectively - through convection in the lungs - when breathing than is the case with air or Nitrox . The hot water suit can therefore be vital for underwater workers, for example. If the hot water supply is interrupted, a diver can die of hypothermia within minutes under extreme conditions (great depth, long dive and low temperature) .
Dry suit
The dry suit or dry suit , also known as "Trocki" in German diving jargon, is a one-piece suit made of water and gas-tight material. Today these are trilaminate membranes made of synthetic plastics or neoprene. The advantage of the dry suit is that the diver hardly comes into contact with water and, if the suit is filled with an insulating gas, is better protected from the cold than in other diving suits. The dry suit is usually sealed with a cuff at the neck and wrist . It has a water and gas-tight zipper on the back or chest for getting in and out. The heat insulation in a dry suit is mainly produced by an insulating gas (mostly air , less often argon ) with which the suit is inflated. In addition, textile protective clothing against the cold is worn under the suit .
The dry suit is also used for snorkeling , surfing, rafting and sailing in very choppy cold water, although these suits do not have any buoyancy control valves .
Membrane drysuit
A distinction is made between dry suits with self-insulation (neoprene dry suit ) and without self-insulation (membrane dry suit ). The latter consists of a trilaminate membrane and does not itself offer any thermal insulation. The insulation is ensured in the wide-cut suit by the insulation gas and the cold protection clothing that is worn underneath. The low insulating effect of the outer skin means that body sweat condenses and gradually soaks the protective clothing against the cold, which in turn reduces its insulating effect. Since the amount of insulation gas between the body and the suit plays the decisive role for its insulation effect, a membrane dry suit can be adjusted relatively flexibly to the temperature of the water. The buoyancy of the membrane material does not change with increasing diving depth, so that the trim and buoyancy behavior of membrane suits does not change with increasing depth. For many divers this is the reason to prefer a membrane dry suit.
Neoprene drysuit
Less insulating clothing has to be worn under a neoprene dry suit, as the neoprene itself already has a heat-insulating effect. The disadvantage compared to a membrane suit is that it is much more buoyant and less flexible, both in terms of movement and its adaptability to different temperatures. With increasing diving depth, the thermal insulation of neoprene decreases due to compression. Therefore, the advantage of better thermal insulation is almost irrelevant for deeper dives. One advantage of the comparatively tight fit is that the insulating gas can only move to a limited extent in the suit, which simplifies handling for inexperienced divers.
There are also suits in which trilaminate and neoprene have been processed into a suit. The attempt is made to combine the advantages of both materials: The well-insulating neoprene is replaced by trilaminate in places where a high degree of mobility is required. Another approach is to provide a dry suit made of membrane material with a thin neoprene outer skin. This thin outer skin does not make a significant contribution to buoyancy or thermal insulation, but it keeps the suit in shape without restricting mobility too much.
Valves
The volume of the insulating gas should be kept constant during the dive in order to maintain the insulating effect and, above all, freedom of movement. Since the gas volume decreases with increasing water pressure, the dry suit must be "refilled" with compressed air or with argon for even better insulation during the descent . To do this, the diver operates the inlet valve on the chest. This is connected to the first stage of the regulator or a separate pressure reducer via a medium pressure hose . In order to be able to remove excess gas from the suit, for example when climbing, a dry suit has an exhaust valve, usually on the left upper arm or sometimes on the forearm. The outlet valve works as a pressure relief valve. As soon as the pressure in the suit exceeds a set value, the valve opens and the insulating gas escapes. Since the valve measures the suit pressure relative to the water pressure, the diver can regulate the gas outlet on the one hand via the valve setting and on the other hand via the water position (raise or lower the valve).
Cuffs and gloves
The dry suit is sealed on the neck - or more rarely in the face area - with a close-fitting latex , neoprene or silicone sleeve. A separate or attached neoprene hood is needed to keep the head warm. Alternatively, the suit can be connected directly to a diving helmet .
Diving gloves are used on the hands . For wet gloves made of neoprene, a cuff is attached to the sleeves of the dry suit, which seals the diver's wrist. Dry gloves are connected to the suit with a gas-tight ring system and supplied with insulating gas via this. There are also suits with tightly bandaged gloves.
Buoyancy
Due to the volume of the insulation gas, a dry suit generates significantly more buoyancy than a wet suit. This buoyancy has to be compensated for by a corresponding downforce - usually by lead weights. The volume of gases is basically pressure-dependent and therefore dependent on the depth. The more insulation gas there is in the suit, the more demanding the buoyancy control . In addition, with a dry suit, balancing the swimming position under water is more difficult because the insulation gas can circulate and always collects at the highest point of the suit. If the diver lowers his upper body too far, the insulation gas collects in the leg and foot area. If there is too much gas in the suit, there is even a risk of a diving accident, as the increased buoyancy makes it difficult to control the water situation and the diver can be pulled to the surface with his feet first. By pulling in the legs, an experienced diver can precisely control the correct distribution of the insulation gas. The use of a dry suit should therefore be practiced in shallow water until a diver can reliably control and change his swimming position.
Theoretically, a buoyancy compensator could be dispensed with for drysuit diving by taring with the drysuit alone. It is recommended that you only dive with a small amount of insulation gas in your suit and that you control the buoyancy with the buoyancy compensator. A leak in the suit can cause the entire dry suit to fill up with water and no longer offer sufficient buoyancy. With the larger amounts of lead that are required for a "dry suit", this can quickly lead to dangerous situations. For this reason, you should never do without an additional buoyancy aid (a buoyancy compensator) when dry diving.
history
The first dry suits were used with classic helmet diving equipment . Entry was through a stretched or very large neckline, the air regulation for suit and breathing was located on the helmet itself. The first dry suits were made of rubberized textiles or leather. It was only with the invention of the gas-tight zipper that dry suits - which are now widely used in the field of scuba diving - independent of a diving helmet became possible.
education
Since diving with a dry suit differs significantly from wet diving, most diving organizations offer special courses to learn how to dry suit . In theory, the diver learns about the differences between the different types of dry suits, their structure and care, and the dangers of dry diving. During one or more dives, the student diver learns how to use the suit and how to react correctly to emergency situations. A prerequisite for such a course is a completed basic diving training . In Europe , dry suit training is also often integrated into basic diving training. This has the disadvantage - even if it is easier - that wet diving has to be learned afterwards.
See also
- Scaphander , an outdated term for a diving suit
- Jellyfish protection suit , special swimwear
- Space suit , gas-tight protective suit for space travelers
- List of clothing items
Web links
Individual evidence
- ↑ Thermal status of saturation divers during operational dives in the North Sea (English), B. Mekjavić, FS Golden, M. Eglin, MJ Tipton: Undersea Hyperb Med. Edition 3/2001, pp. 149–155, accessed: 30. January 2012.
- ↑ Week 6 ( Memento of the original from February 17, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , HDS Germany, accessed January 30, 2012.
- ↑ a b c Sonderbrevets: dry diving ( memento of the original from March 1, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Andreas Nowotny, Augsburg, accessed: October 16, 2012
- ↑ Instructions for use - dry suit and accessories. (PDF) Kallweit GmbH, Pforzheim, March 16, 2011, accessed on September 1, 2019 : “ The air always moves to the highest point of the drysuit, however you change your swimming position. If the moving air is too much it can cause problems. It is advisable to keep the air volume constant and to control the taring via the BCD. "
- ↑ a b Instructions for Use - Drysuit and Accessories. (PDF) Kallweit GmbH, Pforzheim, March 16, 2011, accessed on August 30, 2019 : “ Ingress of water can be caused by cracks, holes and leaks in cuffs or zippers. You should use your buoyancy compensator to return to the surface. "
- ↑ Dry diving ( Memento of the original from February 17, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Tauchsport Uster, accessed on October 16, 2012.
