Everything you wanted to know about drysuits
What is a drysuit?
A drysuit is a type of thermal protection for divers. It’s the wetsuit’s cooler (and in this case, warmer) older sibling. Like the full wetsuit, it covers the diver’s entire body. What separates the two is the drysuit’s ability to keep the diver completely dry through neck and wrist seals and the actual material of the suit. Without water to pull heat away from the diver, they can stay warmer than they would in a wetsuit.
|Drysuits can balloon up if you put too much air in||
One common misconception is that drysuits are totally enclosed – like an astronaut’s space suit – when in fact, the hands and head are open to the water. Tight seals made of rubber, silicone, or latex work to keep water from seeping into the suit and air from escaping. Unless the diver uses dry gloves and a helmet, some of their body will be exposed to water. This is only really an issue in the coldest waters, because the bulk of heat loss is through the body’s trunk.
Due to the more complex steps in gas management associated with the drysuit, additional training is necessary before you can dive in one recreationally. The air in the suit needs to be closely managed because, similarly to a buoyancy compensator, air compresses as the diver descends and expands as the diver ascends. The method for management, however, is quite easy to remember. Drysuits are connected to the first stage via a low-pressure hose. A button – typically on the chest – allows for the addition of air and a one-way valve found typically on the arm allows for exhaust.
There are two different types of zippers found in drysuits: the brass zipper and the plastic zipper. The brass zippers are typically the more traditional style of closures found on most drysuits in circulation today. The brass zipper seals differently than a regular zipper that you would find on a piece of clothing. There are two sets of teeth, a smaller set on the inside of the suit and a larger set on the outside. Instead of meshing the two sets of larger teeth, the slider pulls through the teeth and orients them vertically. This causes the smaller teeth on the inside of the suit to push together and create a vacuum.
The zippers themselves are rugged and hard to break, but the main point of weakness is in the fabric housing the zipper. With each pass of the slider, the fabric on the outside of the larger teeth is abraded by the slider. This can cause it to fray and degrade over time. If the frays reach the teeth of the zipper, this will compromise the seal and cause the zipper lose its waterproof seal. To prevent this from happening, frays should be removed using a razor blade or a pair of small sharp scissors.
Plastic zippers are newer to the drysuit world and work similarly to zippers you find on your clothing – meshing together horizontally. However, they differ by creating a vacuum pocket between the individual teeth, which gives the zipper its waterproof quality. This orientation makes the zipper more flexible, but given the nature of the plastic teeth, too much torque can cause catastrophic damage.
If the zipper is not completely unzipped when removing the suit, it is possible to accidentally wrench the teeth apart and pull the zipper slide off the remaining teeth. We personally recommend that a buddy help you to make sure you don’t damage the zipper when putting on and taking off these suits. Despite the potential of damaging the zipper while putting on/taking off the suit, plastic zippers can last a very long time if they are properly maintained.
The concept of the drysuit predates the invention of the wetsuit and the drysuit configuration seen today is a modified version of the diving dress. A bulky contraption invented in 1837. Because scuba hadn’t been invented yet, air to the suit and the diver was supplied through a surface hose. The drysuit has slowly evolved over the years as scuba has become more popular. One of the biggest problems was the lack of suitable undergarments. The best material for keeping warm was wool which isn’t great for drysuits and is not used today. Although the diver is isolated from water, heat does leak out because the water is colder than the air inside the suit. Effective undergarments are needed to keep body heat in.
In the 20th century, divers were able to explore further beneath the surface through the invention of scuba. World War II saw an improvement to drysuits as combat divers needed more streamlined suits. The invention of neoprene in the 1930s sparked a new idea in the diving world and brought us the first commercially available wetsuits in the 1950s.
The waterproof zipper, also invented in the 1950s, made drysuits much easier to get on. Interestingly enough, NASA created the waterproof zipper to keep the vacuum of space from affecting astronauts while they were using spacesuits. That means that all drysuits are cousins to spacesuits! Prior to the invention of this zipper, the drysuit was put on in separate pieces and sealed together. This was a much more tedious process and thankfully the drysuit has evolved since then. New materials allow the drysuit to be more streamlined and sturdier, while innovations like internal suspenders make the suits easier to don. Who knows which cool ways drysuits will evolve in the future.
Contrary to what you may think, drysuits aren’t just for recreational use. Also known as survival or exposure suits, they’re also common in commercial diving, the military, and are often present in boats and submarines. If the crew has to evacuate, these suits ensure that they stay warm and dry in the water while they wait to be rescued.
Types of drysuits
Drysuits can be made of neoprene, the same material that wetsuits are made from. Neoprene drysuits are similar to wetsuits in the respect that the material itself still absorbs water. However, due to some minor adjustments, water doesn’t enter the interior of the suit. These suits have the waterproof hand and foot seals instead of open cuffs, the seams are joined with glue instead of being sewn, and the zipper is waterproof.
Laminated materials are thinner and lighter than neoprene, so drysuits made from laminate tend to also be thinner and allow for more room between the suit and your body. The material absorbs minimal water over the course of the dive, making it virtually the same weight whether wet or dry. It’s also much easier to clean after a dive – a simple rinse and you’re done. Because of the lightweight quality of the material, thicker undergarments are typically added to compensate for colder temperatures. However, this also allows the suit to be used with thinner undergarments in warmer waters. You simply adjust the thickness of your undergarments and you’re good to go. This allows laminate drysuits a level of versatility not seen in their neoprene counterparts.
Something to note is that there are exceptions to both of these categories. Some suits can be considered hybrid suits because they utilize a combination of both materials in different parts of the suit. One notable example is Aqualung’s Fusion drysuit line, which has a laminate inner shell and a thin neoprene outer skin.