For cold water diving do you use a wetsuit or dry suit?
If you’ve only ever dived using a wetsuit, then to you maybe wondering what the difference is between a wetsuit and a dry suit. Let’s take a look at what each is, which will help to explain what the differences are.
The main difference between a wetsuit and a dry suit is that in a wet suit you get wet, whereas a dry suit keeps you dry. Other differences include; dry suits are designed to be used in colder waters and tend to be more expensive than wet suits. Plus a dry suit can also be used for buoyancy control instead of using your buoyant control device, whereas a wet suit can’t.
What is a wetsuit?
Wetsuits are made from neoprene. To help protect the neoprene from damage and from being perished by the sun it’s usually covered with a layer of stretchable material.
Wetsuits come in varying degrees of thickness starting from around 2-3mm thick. The thickness of the neoprene affects the thermal property of the wetsuit. The thicker the neoprene, the warmer it will keep you. But there is a threshold of cold where a wetsuit will no longer keep you warm underwater, which is when a dry suit becomes a better option.
Do wetsuits keep you dry?
Wetsuits work by using a combination of the thermal properties of the neoprene, together with the warmth gained from a thin layer of water. This thin layer of water lies between the wetsuit and your skin. It is your body temperature that warms this thin layer of water up. Once warmed, it helps to keep you warm throughout your dive.
It is therefore the case that wetsuits do not keep you dry. You are therefore wet when you finish your dive, hence the name ‘wetsuit’.
Do wetsuits work?
Yes wet suits work well in waters that aren’t too cold. But where a wetsuit may let you down is if you're going to be doing a second dive. This is especially true on a cold day.
A ‘wet’ wetsuit out of water works in the opposite way to how it works underwater. If it's a cold, wet and windy day and you're on a dive boat, you'll struggle to get warm in-between your dives.
When you get kitted up for your next dive and jump back into the cold sea, you'll feel the cold much faster. When that fresh flush of cold water hits you, after never properly warming up, you may not be too happy. This means you'll get colder much sooner.
You could opt to taking your wetsuit off in-between your dives. But whilst this will help you to warm up on your dive interval, you've still got to get back into a wet and cold wetsuit before your next dive. It's extremely unlikely it will dry out in-between your two dives.
Do wetsuits keep you warm?
Yes a wetsuit will keep you warm, subject to how cold the water gets. In really cold waters you are better off using a dry suit or alternatively you could use a semi-dry suit instead.
Can you swim in a wetsuit?
Depending on the thickness of the neoprene of the wetsuit, it’s okay to swim in one. In fact wetsuits are used by surfers who need to paddle out to the waves. The flexibility of the neoprene allows full arm movement when swimming.
What is a dry suit?
A drysuit provides scuba divers with better thermal insulation than other exposure suits like wetsuits and semi dry suits, as the wearer is kept dry.
There are three types of dry suit. These include neoprene drysuits, crushed neoprene and membrane drysuits. Each one of these dry suits has it's own properties and benefits or advantages vs its disadvantages over the other.
But all three types of drysuit described provide thermal protection at the same time as keeping the wearer dry.
With a drysuit the thermal warmth is provided as follows:
- Neoprene drysuit. The thickness and thermal properties of neoprene keep you warm. Plus the thin layer of air around your body inside the suit is what helps to keep you warm.
- Crush neoprene drysuit. It's what you wear underneath this type of drysuit that will keep you warm, which is typically a woolly-bear. It is the thermal properties of the woolly bear, together with the layer of air inside the suit that keeps you warm. You can buy a 'woolly-bear', which is a effectively a thermal onesie to keep you warm.
- Membrane drysuit. The way this keeps you warm is similar to a crushed neoprene drysuit, which is by using a thermal undergarment under the membrane drysuit.
Do drysuits keep you dry?
Drysuits are designed to keep you dry and they do. However, over time drysuits can spring a leak. Leaks can form around the wrist and neck seals or where the suit itself gets punctured.
It's quite easy to have a drysuit repaired if it has a leak. But when you expect to be dry on a dive, it's not a nice experience when you discover a leak when you're underwater and cold water seeps in!
Do drysuits work?
Drysuits are designed to fit more loosely than wetsuits. They allow you to wear clothes and/or other insulation layers underneath, as explained above.
As describe previously, drysuits work by keeping an insulating layer of air between your body and the suit. It is this layer of air, combined with the insulating properties of either a neoprene drysuit or the thermal clothes under a crushed neoprene or membrane drysuit that makes it work well.
Drysuits work well in cold waters and can be used in freezing cold waters of the Arctic or Antarctic or perhaps when diving in a frozen lake.
The air in a drysuit is controlled using an inflator hose attached from your air supply to a valve on the suit. This inflator valve allows you to add air as you go deeper. This acts as your buoyancy control, instead of you using your buoyancy control device or BCD.
What is a dry suit used for?
As a general rule drysuits offer better insulation than wetsuits or semi drysuits. This is especially true when used in cold water and makes them more suitable for this type of use.
Drysuits are often used by commercial divers on oil rigs, by police divers who dive in cold rivers or lakes and by recreational scuba divers who dive in colder waters around the world.
Typically drysuits are more expensive than wetsuits or semi-drysuits. They are also a bit more complex to put on. They also require additional training before they can be used by scuba divers.
The extra training is because of the buoyancy qualities of a dry suit and the fact that when you're drysuit-diving, the drysuit is used for buoyancy compensation rather than your BCD.
More Reading: How To Achieve Neutral Buoyancy Scuba Diving (Made Easy)
Do dry suits keep you warm?
Drysuits certainly keep you warm in cold water. But how warm you are when you're using a drysuit is dependent on the amount of insulation you use. For example, with a neoprene drysuit, you'll only be as warm as the thickness and thermal properties of the neoprene of the suit.
Whereas with a crushed neoprene and a membrane drysuit, you're only as warm as the undergarments worn and their thermal properties.
The colder the water, the better the insulation is needed to compensation and to keep you warm when using a drysuit.
Can you swim in a dry suit?
Swimming in a dry suit would be quite challenging and is not generally something that is done. A drysuit is more restrictive for movement than a wetsuit is, as they are designed for comfort and warmth rather than for physical exertion
If you're looking for thermal insulation for swimming, you're better off using a wetsuit instead.
What do you wear under your drysuit?
As discussed earlier, with a crushed neoprene drysuit you wear warm insulating clothes. The same goes for a membrane drysuit. But for a neoprene drysuit you just wear shorts and a t-shirt.
In really cold weather and if the water temperature is really low, you'd be advised to wear two layers or better thermal insulation.
What causes dry suit squeeze?
As you dive deeper, the air inside your drysuit gets squeezed. As already mentioned, if you're diving using a drysuit, you're better to use the drysuit as your method to achieve neutral buoyancy than you are to use your buoyancy control device.
However, drysuit squeeze is caused on your descent. It is caused where you fail to add enough air to your drysuit during the descent. It's not really a problem, and you soon notice it when you forget. You'll feel it most beneath the valves and seams of the suit as these push against your skin.
To overcome dry suit squeeze is a simple matter of adding more air using the inflator hose.
What is the difference between a wetsuit and a dry suit
In summary, the easiest way to remember the difference between a wetsuit and a dry suit is that a wetsuit let water in, whereas a dry suit doesn't.
But let's list what are the main differences between a drysuit and a wetsuit:
- Wetsuits are used in warmer water temperatures than a drysuit, which are designed for colder water temperatures.
- Drysuits have better and tighter fitting seals to keep the water out. Whereas wetsuits have seals that are designed to flush water.
- Drysuits tend to be more expensive than wetsuits.
- A drysuit is effectively used as your buoyancy control device, whereas a wetsuit isn't.
- Drysuits keep you warmer out of water and in-between dives compared to wetsuits which tend not to.
- Drysuits tend to be made of heavier and stronger insulating materials to help keep the wearer dry and the water out.
I hope you enjoyed this article about what is the difference between a wetsuit and a dry suit
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