If you plan on diving in Europe or North America, most likely you would have come across a ‘drysuit.’ This is a piece of optimal equipment when planning cold water or a technical dive. But how does a drysuit work, and when would you really need to use one?

how does a drysuit work?

WHAT IS A DRYSUIT?

Simply put, a drysuit is an exposure suit that keeps you dry. Most commonly, a drysuit is used by scuba divers or snorkelers who are diving in cold or icy conditions. It keeps the person warm so that they do not get affected by the cold water.

HOW DOES A DRYSUIT WORK?

We lose body heat a lot faster in water than on land. This is why 20 degrees on land might be pleasant, but absolutely freezing when going on a 45-minute dive!

How does a drysuit work is by insulating your body with air instead of water. It will be watertight as the drysuit will have rubber seals around the neck and wrists of the suit. This stops the cold water from getting in and making contact with your body. Because your body will be dry, you can wear anything underneath! Thermals and cotton wear are typical as the drysuit itself is not heated. You can layer on however many items you want under your drysuit as long as it doesn’t affect your movements!

BUOYANCY WITH A DRYSUIT

Because your exposure suit is filled with air, this will greatly affect your buoyancy and you will float around like a balloon. This is why you would need more weights to dive than your usual amount when diving with a wetsuit. You will also need to compensate for the pressure change when diving deeper or shallower as this will affect the air in your drysuit. As you go deeper, the air inside will compress and you will have a risk of SQEEUZE – this is when you would add small amounts of air to your suit. And as you ascend and the air inside expands, you will need to release small air from valves on your suit. Because of the major differences in buoyancy when diving with a drysuit, you should always find an expert and first practice diving with your new suit in a controlled environment. 

DRY SUIT DIVING VS WETSUIT

A wetsuit will get the wearer wet. This is because a properly fitted wetsuit works by trapping some water in-between your skin and the suit. Your body heats up this trapped water and you feel slightly warmer. Wetsuits will be made out of neoprene, an insulating fabric that is made out of synthetic rubber. Neoprene is flexible and long-lasting and spongy to the touch. This means it will compress and get thinner under pressure, for example, when you dive to deeper depths.

Wetsuits are very typical in the tropical scuba diving world as it provides some warmth and little restriction for diving. Typical thicknesses of wetsuits are 3 millimeters, 5 mm and 7 mm, with the thicker the wetsuit, the warmer it is.

Drysuits will keep you dry. These are used when a wetsuit is not warm enough for the conditions. This will differ for each person based on their comfort level.

WHEN DO YOU USE A DRYSUIT?

Choosing to use a drysuit will depend on your activities, how long you plan on being underwater and your comfort level.

For recreational diving most people will find that water temperatures under 15 degrees Celsius / 59 degrees Fahrenheit will be uncomfortable, even with a wetsuit, and will opt to wear a drysuit. If you are diving in Norway where the temperature of the water is usually 2°C / 35°F, or just barely above freezing. This is when you would definitely need a drysuit.

Technical divers will dive for longer and exceed our normal recreational dive limits. They may also use a different blend of gas to breathe. Because of the amount of time they need to decompress, taking hours and sometimes days to come back up, they will get cold after being in the water for so long. Even in tropical temperatures. This is when you would also be wearing a drysuit. Just make sure you take the drysuit off on land straight away so that you don’t overheat and get heatstroke!

Living in Thailand, the water temperature is generally a balmy 29°C / 84.2°F. But because we dive every day, our bodies get used to the warm temperature and when we suddenly find a temperature drop to 26°C / 78.8°F during monsoon, this is when some of us can struggle. Unbelievable I know, but a Divemaster colleague of mine bought a drysuit in the UK and brought it back to Thailand to use! 

THINGS TO CONSIDER WHEN GETTING A DRYSUIT?

Photo by Thomas

The Fit of a Drysuit

Sizing and fit is very important when choosing a drysuit. How does a drysuit work is that it fits well and is not too tight or will leak. As the drysuit is already bulky and cumbersome, you do not want a suit that is too big and even more awkward to move around in. Most divers who wear a drysuit will have their own personalized and custom-made drysuit. Rental drysuits may cause a lot of problems if not properly fitted.

Carotid Sinus Reflex

While you will want the neck and wrist seals to fit snugly to stop water from getting in, you certainly do not want them too tight. Neck seals that are too tight can constrict your neck and breathing. This can also cause a condition called carotid sinus reflex, where your heartbeat can slow down and slow down the flow of blood to your brain. This can cause you to feel dizzy and even lose consciousness. Wrist seals that are too tight will be uncomfortable and may cause tingling and numbness in your hands, which you may confuse with symptoms of Decompression Sickness (DCS). 

Heatstroke

Overheating can be a serious danger when using a drysuit. As funny as it sounds, my colleague loves wearing his drysuit in Thailand. However, when the land temperatures can get very hot and humid there is a very serious risk of overheating and getting heat exhaustion and heatstroke. Heatstroke can cause dizziness, hot and dry skin, vomiting, rapid heartbeat and possibly be fatal. This means when you finish the dive, you should take the drysuit off completely and drink plenty of water. 

Leaking drysuit

Leaking in a drysuit would not be comfortable. A large leak in a drysuit would render the suit useless. Your clothes would get wet, and you would get cold very quickly. However, a small leak during a recreational dive can be managed and you can continue the dive if you wish. This is a personal preference. A Norwegian buddy of mine dives at home regularly, and he says that after getting his drysuit on, and carrying his equipment over a large distance of snow, a small leak is not enough to end his dive. He claims a small leak is not instantly recognised during a dive, except for when he takes off his drysuit and notices his clothes are all wet!

Change of Buoyancy

Buoyancy is super important during a dive. Even more so when using a drysuit. This is because the drysuit will act as a buoyancy device and will compress and expand as you go up and down. You will need to know how much air to add to your drysuit as you descend and you suit contracts. Drysuit squeeze can cause bruising, especially under the valves and zips. You will also need to know how to locate and release the valves on your suit so that you do not make a rapid and dangerous ascent.

Using accessories

Did you know most dive computers and compasses will usually come with an extraordinarily long wrist strap? This is to use with a drysuit as your arm will probably twice as bulky than normal. This is something to bear in mind before you cut the long strap off – if you plan on using the same computer/compass in cold water, keep the long strap!

Also bear in mind that gloves will make clearing your mask, pushing dive computer buttons, and using your drysuit valves trickier due to its bulkiness. Always practice using unfamiliar equipment before a dive.

Putting on and taking off a drysuit can be difficult due to the weight and the bulkiness. This means when nature calls, it can be annoying to keep taking the suit off and on. So what to do when you feel the urge to pee in a drysuit?

HOW DOES A DRYSUIT WORK WHEN YOU NEED TO PEE?

We get told to drink a lot of water and hydrate while scuba diving. This is mostly because we can get dehydrated easily when diving in a tropical and humid environment. But also important when you are doing strenuous activities such as carrying heavy dive equipment and swimming on the surface. Even in cooler climates. So if you drink a lot of water, then surely it must come out too. This is when you need to consider how to go to the toilet when using a drysuit. 

Drysuit Urine Collection Device

For men, it is slightly easier. You will connect a P-valve system to attach to your inner thigh before donning your drysuit. It is a condom catheter that will collect your urine and release it out of a tube on the outside of your drysuit.

For women, it is similar, however, you will be using a cup-like device. Both gender systems, however, can and will possibly leak. So another alternative is wearing adult diapers which are designed to absorb your urine. But again this is not fool-proof. The other options are to just go freely and pee inside the suit, or take the advice of some divers, and eat something salty before the dive, which apparently suspends the urge to pee!

CONCLUSION

So you can see that a drysuit is a type of exposure suit that is most suited to cold water diving or longer duration dives. How does a drysuit work relies on the air surrounding your body to feel warmer, and it is important to keep your drysuit sealed and fitted for it to work correctly. Because of the air in your suit, you will need to carefully consider and practice your buoyancy to safely dive. You will also need to make sure you don’t overheat when on land, and think about the options to relieve yourself during a dive in a drysuit! All in all, a drysuit is a very useful piece of equipment when diving but it is different from diving in a standard wetsuit!

Emma was terrified of the ocean but dove into her Open Water 7 years ago and hasn't looked back since! She worked as an underwater videographer for several years and is now a PADI Master Scuba Diver Trainer. She currently runs a dive shop on the island of Koh Tao in Thailand and is the founder of Down To Scuba.

LEAVE A REPLY

Please enter your comment!
Please enter your name here