How Drysuits Work
Drysuits are commonly worn for a variety of sports and occupations. This article looks at how drysuits work and how they are used in sports and leisure activities.
What is a drysuit?
A drysuit is a fullbody garment that is designed to keep the wearer dry when immersed in water. Clothing of some sort is normally worn underneath a drysuit and this will also remain dry throughout the activity.
What makes up a drysuit
Most drysuits are made up of several key parts:-
Fabric body of suit (Arms legs etc)
A sealable way of entering the suit (Zip)
A method of sealing the extremities (Neck, wrists and ankles)
We will look at each of these in turn.
MATERIALS AND BODY CONSTRUCTION
The body of a drysuit is, in the main, made from one of three different material types. Drysuits used for surface sports such as sailing and kayaking tend to be made from waterproof breathable fabrics and are very flexible. The panels are sewn together then the seams are normally sealed with seam sealing tape. This tape is applied by a seam sealing machine that heats up the tape and applies it to the seam through a series of rollers. This results in a strong and flexible seam that is watertight.
Drysuits used for diving are normally either made from crushed neoprene or a 3 layer material (sometimes referred to as membrane material). Crushed neoprene is similar to the material that wetsuits are made from expect that it has been compressed or partially flattened. Different manufacturers have different ways of doing this. 'Membrane' material is normally a tough material like Nylon on the inside and outside with butyl rubber in the middle.
There are some surface drysuits that are made from membrane type fabrics. These are popular with emergency services as the material is more robust than a breathable garment. The down side of these garments is that they can be less comfortable to wear for long periods of time.
ZIPS
Because the wearer needs a way to get into this completely sealed suit it is necessary to put an entry zip in the product. This cannot be just any old zip, but must be a special type of zip called a "dry zip". There are 2 main types of dry zip, commonly referred to as metal or plastic. Dry zips have teeth that fit very closely together to keep the water out.
Generally speaking metal zips are able to stand up to higher water pressures before leaking and are favoured on diving drysuits where the extra water pressure at depth poses a greater challenge to staying dry. Some surface sport drysuits also use metal dry zips.
Plastic drysuits tend to be more flexible and have a lower cost than metal zips and perform very well indeed on suits for sports such as kayaking and sailing. They are still uncommon on diving drysuits as most diving suit manufacturers prefer to rely on the extra resistance to water pressure given by metal dry zips.
The zips can be located either across the shoulders at the back of the suit, or diagonally from one shoulder down to the opposite hip. These two styles are commonly referred to as 'rear entry' or 'front entry' respectively.
RELIEF ZIPS
Some drysuits feature an extra 'relief zip' to enable a male to 'take a leak'. Women aren't quite so lucky and most drysuits don't have a different zip setup to allow a female to do the same. A device, which resembles a medical bottle, is available that allows a woman to use the same relief zip as a man.
UNDERSUITS
Breathable drysuits and membrane drysuits do not have significant insulating properties in their own right and rely on a layering system worn under the drysuit to keep the wearer warm, not just dry. These can vary from lightweight fleece all in one garments to multi layer suits with layers of fleece, thinsulate or other insulating material. Divers tend to wear thicker undersuits than surface sports users.
Neoprene drysuits have more insulation built into the suit by virtue of the thickness of the neoprene. Some users find they need only wear base layer garments under a neoprene suit whilst others may still wear an additional undersuit.
CUFFS
Most drysuit cuffs are made from latex rubber and form a tight gasket around the wearer's cuff that is sufficiently tight to prevent water getting between the seal and the skin.
Some seals are made from neoprene rubber but this is relatively uncommon and usually requires a larger amount of material to be in touch with the skin in order to make the seal effective.
NECK
Most drysuit neck seals are made from latex rubber and squeeze quite tightly around the wearer's neck in order to make an effective watertight seal. Some drysuits use neoprene neck seals which tend to be larger and, just like cuff seals, require a larger amount of material to be in touch with the skin in order to make the seal effective.
ANKLES AND FEET
At the foot end there are 3 different options for drysuits; ankle seals, socks or fitted boots.
Ankle seals are larger version of the wrist seals and grip tightly around the lower ankle area. They can be prone to leaking as the tendons on the back of the ankle can make it difficult for the seal to fit snugly all the way around some peoples ankles. Also, the added pressure to the ankle restricts blood flow to the foot which can make a persons' feet very cold indeed. Many people see the only obvious application for ankle seals is in sports where a bare foot is necessary; waterskiing would be an example of such a sport.
Socks are generally of 2 different types; latex socks or fabric socks. Latex socks are made from the same materials as the latex neck seals. They are normally sewn onto the leg of the drysuit then seam sealed in the same fashion as the rest of the seams. This type of sock is reasonably tough. Small holes can be repaired with a puncture repair kit and the material is tough enough to be walked upon if wearing shoes over the top. Over a long time period latex rubber can perish and it should be kept out of strong ultra violet light and sources of ozone as this hastens the perishing process. Other materials, such as some insect repellents can also cause perishing to the rubber. If looked after, latex socks perform well on drysuits and will last for many years. It is normal to wear regular, woollen type, socks inside a latex socks for warmth and comfort as your feet can sweat badly if used without.
Fabric socks are normally made from the same, or similar, material to the main body of a breathable drysuit. They are breathable which may provide a benefit when compared to latex socks, however, wetsuit boots are normally worn over the top of these socks and neoprene doesn't breathe at all so the breathable benefit of these socks is lost in most situations. Certain breathable socks can be prone to leaking at the seams as the process of walking on them, and hauling wetsuit boots on top of them, can cause quite high forces in certain situations. Small holes can be patched and glued whilst it may be possible to repair leaky seams with an adhesive sealer or by replacing the leaking seam tape.
Fitted boots are normally only found on diving drysuits. These boots resemble short welly boots and are often quite roomy. It is normal to wear thick warm socks with these boots. Fitted boots are normally quite durable and require little maintenance.
CONCLUSION
In cold conditions it is hard to beat a drysuit for keeping warm in the water. Even thick wetsuits struggle to keep you anywhere near as warm and comfortable. Drysuits tend to be more expensive than wetsuits though and are beyond the reach of many beginners.
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