What is the cause of dry suit squeeze and how to prevent it from happening
What causes dry suit squeeze is the pressure of the water increasing around you as you descend on your dive. But how do you prevent dry suit squeeze and is it dangerous?
What causes dry suit squeeze is the result of increased pressure of water around you as you descend on a dive. The air pocket inside your dry suit is squeezed, and as a result the material of your dry suit is pressed against your body. Dry suit squeeze is particularly uncomfortable around the valves and seems of your suit.
What is dry suit squeeze?
If you’re not sure what dry suit squeeze is, let me quickly explain what it is.
As it is the job of a dry suit to keep you dry, it then follows that the inside of your dry suit will be filled with air. This is as compared to a wetsuit, which has a thin film of water between the wetsuit and your skin. The concept of a wetsuit is your body warms this thin layer of water, and combined with the thickness of the neoprene, this is what keeps you warm.
But for a dry suit it’s a combination of the air inside the suit and the material it’s made of, together with any undergarments you wear that keeps you warm underwater. But the undergarments you need to wear will depend on the water temperature and the type of dry suit you use.
It is the fact that you are surrounded by a layer of air inside your dry suit that results in dry suit squeeze.
It is this layer of air that is responsible for the cause of dry suit squeeze. But see below why this happens and how to prevent it.
Pressure increases as you dive deeper
As you are probably aware, as you descend on a dive the pressure of the water at depth increases. The deeper you go the greater the pressure.
You will also be aware that ‘air under pressure’ reduces in volume. This change in volume is described using Boyle’s Law. Your dry suit is a bit like a large balloon. If you were to take an air-filled ballon to depth, it would reduce in size and volume. The deeper you take this air filled balloon, the smaller the size and volume would become.
With this concept explained, let’s now take a look at what causes dry suit squeeze in more detail.
What causes dry suit squeeze?
Now that I’ve explained the concept of a dry suit and how there’s air inside the suit, let’s take a look at what causes dry suit squeeze.
It is the reduction in air volume of the air that surrounds you inside your dry suit that causes the dry suit squeeze. This is because, as the air volume is ‘squeezed’ the material of your dry suit squeezes against your body.
This squeezing against you of your dry suit is most noticeable in the first 10-20 metres of descent. This is due to the fact that the pressure increase during this part of your descent has the biggest change.
Probably the best way to explain what dry suit squeeze is like is to compare it to a Vacpack. Vacpacks are used to store bedding and pillows etc. With a Vacpack the air is sucked out until the pack squeezes whatever you've stored inside. Take a look at this video and you'll see what I mean.
What you see happen with the Vacpack is exactly what a dry suit would look like at depth without the addition of air during the descent. The only difference being is that with a Vacpack the air is sucked out, whereas with a dry suit the air is squeezed under pressure.
How do you prevent dry suit squeeze?
Dry suit squeeze is quite easily prevented or corrected if you forget to avoid it happening in the first place.
As a dry suit diver, you have an additional air hose connected from your air supply. This air hose connects to the air inflator of your dry suit and is called your ‘dry suit inflator’.
Before you enter the water and as already explained, your dry suit will have air inside it. But as you commence your descent, this air will be squeezed as the pressure begins to increase.
Adding air to your dry suit prevents dry suit squeeze
In a similar way to adding air to your buoyancy control device (BCD), you simple add small amounts of air to your dry suit to compensate for the reduced air volume.
As long as you add air in small amounts during your descent and at the correct volume increments, you should never suffer from dry suit squeeze.
But even if you forget to add air as you descend, you’ll soon realise it. This is because your dry suit will begin to squeeze you. The longer you leave the addition of air on your decent, and the further you descend without adding air, the more you’ll be squeezed.
Is dry suit squeeze dangerous and does it hurt?
As far as I’m aware dry suit squeeze isn’t dangerous. This is other than if you were to dive to an extreme depth and didn’t add any air. In this case you may find that it could cut off your circulation.
However, I’d like to think that the ‘pain’ of this intense dry suit squeeze would be enough to prompt you to add air via your dry suit inflator. This should be a long time before it becomes dangerous.
There's a chance that you could suffer from bruising due to drysuit squeeze. But this may be influenced by the type of dry suit you wear and how much you’re squeezed.
If you were to get bruising from dry suit squeeze, this is more likely to occur around or beneath the valves and seams of the dry suit.
I hope you enjoyed this article about what causes a dry suit squeeze
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Have fun and be safe!