Guide to scuba diving drysuits: Divers drysuit FAQ

May 30, 2019 BY AWE365 Team

If you dive in cold waters you need to read this guide to scuba diving drysuits. I aim to cover all the common questions in this divers drysuit FAQ.

Not only do drysuits keep you dry but they offer another significant advantage over wetsuits. Namely they keep you warm out of the water as well as in it, because they withstand the cooling effects of the wind.

Guide to scuba diving drysuits Wikimedia CC image by Travail Personnel Emdx

Not just a bonus, but essential when your diving trips are in less than cold conditions. Be prepared to invest both time and money however, because a drysuit will cost quite a bit more than a wetsuit and requires training to use it properly.

Guide to scuba diving drysuits

For those dedicated divers that are happy to dive in waters below 10 degrees centigrade. Firstly, bravo! You are more committed than me, a self-confessed warm weather scuba gal.

Secondly, you may know to keep yourself warm by wearing a drysuit. But are you fully up to speed on how to choose the right one for you?

Do you know how they work? What they are made of? How to size one? And what to look for in good scuba diving drysuits?

Divers drysuit FAQ

In this guide to scuba diving drysuits we look at what divers need to know before they buy dry.

How do drysuits work?

Drysuits work by keeping the water out whilst trapping a layer of air next to your skin. This is the opposite of wetsuits that trap a layer of water.

Divers drysuit FAQ Flickr CC image by Joi

As air is a better insulator of heat than water and you want to be kept warm, the whole wet/dry thing is pretty straightforward. You with me so far?

What are drysuits made of?

There are two major types of material – trilaminate and neoprene.

Trilaminate is essentially a triple layer of airtight membrane. It is easy to get on and off, and to repair, but does require a thermal layer underneath.

Many divers find trilaminate drysuits easier to manoeuvre in. They are quite distinctive by their ‘baggy’ look, which may feel weird for divers used to a snugger fit.

Neoprene will be more familiar as it’s what most wetsuits are made of. In drysuits it’s very warm and hard-wearing, but due to the close fit can be tricky to get on and off.

Plus the nature and density of the neoprene makes it very buoyant. Crushed neoprene tackles this to a degree, but you may also lose some warmth.

Guide to scuba diving drysuits Divers drysuit FAQ Wikimedia CC image by Martin Nieuwoudt

How do they keep water out?

This is a common Divers drysuit FAQ. On a drysuit there will be tight seals at the neck and wrists. Some manufacturers use neoprene seals and some use latex.

When you first use your suit, the seals will almost certainly be too tight. If you look on the inside of the seals, you will notice thin rubber rings, these show where the seal can be cut back. This will improve the comfort and fit of your seal.

A word of warning, only cut off one ring at a time to make sure you don’t cut too much and end up needing a new seal straight away. The seal should still be tight after trimming.

Over time the seal will loosen, but it should not be so tight as to cause dizziness or tingling at the start. Latex seals tend to be the most efficient. Over time they will perish, although they can be replaced.

Why do scuba diving drysuits cost so much?

Materials, technology and size of the market all add to the costs. But who knew that the waterproof zip fitted in your drysuit would be the single most expensive element? But hey, it’s pretty important in the scheme of things.

Always take care when closing and opening your suit and always ask a buddy to help. Trapped undergarments could cause a leak, which would be scary and dangerous. Run a wax stick generously along the suit zipper, to keep its movement free and easy. Oooer missus.

How do I ensure my drysuit fits?

The most important section in this guide to scuba diving drysuits. When deciding on the correct size of drysuit first consult the manufacturers size chart. Height should be comparable, wrists and neck seals should be snug.

Divers drysuit FAQ Flickr CC image by Joi

The body should be baggy enough to allow a thin layer of clothes beneath. When trying it on, wear what you would to go diving in. The suits are often cut slightly larger than the size charts, but this extra layer allows for movement and an undersuit.

So now you’re modelling the equivalent of an attractive human size VacPac. You really need to make sure this suit works for you.

It should be closed and zipped up. Then, pull out the neck seal to release excess air as you crouch down, letting go of the neck seal before you stand back up. With your feet flat on the floor, you should then try to kneel.

This is to make sure the legs are long enough for you to move easily, and get in and out of the boat without requiring a crane. It also means if you ever want to propose whilst wearing your drysuit you’ll be fine.

If you find it pulling and uncomfortable in the crotch area – never a good feeling – the suit is too short for you. Whilst on your knee, give yourself a big hug too, to check you have enough flexibility across the shoulders.

Dressing room humiliation complete, you can feel reassured you’ve found the right size of drysuit for you.

Tips for choosing scuba boots Divers bootie call Wikimedia commons image by US Navy

What about my feet in a drysuit?

A drysuit is essentially a waterproof ‘onesie’ and so comes with built in booties. The boots should not be too large and if you plan to wear thermal socks these should be worn when testing the boots.

As a general rule of thumb go for your standard shoe size. Or one size bigger if using a thermal underlayer.

Why does a drysuit have valves?

The next thing to consider is valves. Now, are you listening carefully?

The valves allow air to enter and exit the suit whilst submerged. Once you go into the water and start descending, the pressure on your suit increases.

This compresses the layer of thermal air between your body and the suit, reducing insulation and buoyancy. So if you don’t pump air into the suit, the expression ‘sink like a stone’ becomes more of a reality.

The inflator or inlet valve is your BCD equivalent. It is connected to your 1st stage, and allows air to enter the suit by depressing the button on the front of the valve. This valve is generally located in the centre of the chest.

How to a let air out of a drysuit?

To let air back out of the suit, there are two types of dump or outlet valves available on dry suits. You’ll either have a cuff dump or auto shoulder dump. Who thought we’d be taking about dumps in this divers drysuit FAQ!

Guide to scuba diving drysuits Wikimedia CC image by Travail Personnel atsme

The cuff dump as the name suggests is located near the wrist on the cuff. It is operated by raising the arm to the highest point where the air pressure within the suit causes the one way valve to open and expel the excess air.

The shoulder or auto dump is again as the name suggests located near the shoulder. But it is slightly more sophisticated than a cuff dump.

An auto dump has a pressure sensitive spring, which should allow it to automatically release excess air from within the suit. In practice it is not as automatic as the name would suggest, with the position of the valve being critical to its efficiency.

So the point is, valves will differ from suit to suit. Positioning of the valves may vary. Again, it depends on the kind of diving you are doing and your own preference.

Older style valves might be more high profile against a suit – i.e. they are more raised, but more familiar. Newer ones, less raised, less familiar, but more efficient.

Guide to scuba diving drysuits: Final tips

Ask lots of questions when trying and buying your drysuit. You are the customer and ease of use, safety and comfort are crucial when making this investment. All drysuits should have the European CE Safety marking.

Divers drysuit FAQ Flickr CC image by Joi

Do try your new drysuit in a pool or safe dive before taking it into a situation where your life depends on it. Not only is it a good way to become aware of its characteristics or tweaks or you need to make, but in case of a defect you will not be in serious trouble.

If you’re reading this divers drysuit FAQ then I’m assuming you’ve done your training on how to use one. If not, do that first! This is not something you want to learn on the job.

We hope you found this guide to scuba diving drysuits useful. If there is anything we should add this divers drysuit FAQ please leave a comment.
Be sure to check out out scuba diving holiday discounts as you could save a fortune on your next trip.


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