Why do you get dry suit squeeze and not wet suit squeeze?

[H2Andy]

so how do you account for the difference between wet suits and dry suits then?

provide an alternative to the compressible fluid hypothesis

 

[Soggy]

Still makes no sense.

Picture a 1 square inch tube pressed against your skin. Now pump it full to 50psi with air, water, bananas, oil, or jelly. The pressure exerted against your skin is going to be 50psi in all cases.

If you let half the air out of the dry suit, the air pressure inside won't be halved, the volume will be halved because the water will press the suit in until the pressure is equalized.

What if the dry suit fit so well that there was NO air in it?

I'm thinking Pascal has something to do with this.

http://www.scubaboard.com/showpost.php?p=2739701&postcount=12

If the drysuit had no air in it, that would be the ultimate squeeze.

 

[Web Monkey]

Why do you get dry suit squeeze and not wet suit squeeze? In both suits you have water pressure against you, so why do dry suit people get the squeezed, can't breathe feeeling?

Drysuit squeeze is caused by the water pressure squeezing folds of the suit together, making the suit smaller, which then squeezes you.

Adding air relaxes the folds and loosens the suit.

That's why drysuit "hickeys" are always where the creases were.

Terry

 

[Kstnbike]

I think what Reefhound doesn't understand is that: There is still the same PSI of air in your suit at the surface and at depth if you didn't add air, the volume is just different. In order to account for the lost volume of air due to increased pressure, you have to periodically add more air to your drysuit with air from your tank. When you add air at depth, you are increasing the PSI and volume within the suit. When diving a wetsuit on the other hand, water doesn't lose any volume as you descend or ascend, so there is no suit squeeze. As a drysuit diver ascends to the surface, the added air (added PSI and volume at depth) in the suit begins to expand. Therefore as a drysuit diver ascends, they need to vent the air added at depth in order to maintain neutral buoyancy.

I think that covers it. Perhaps a little confusing to some, but I've had a long day...

-Kstnbike

 

[Thalassamania]

Drysuit squeeze is similar to mask squeeze, if you don't add air it hurts. If your mask is full of water, no problem ... right?

 

[Kstnbike]

Drysuit squeeze is caused by the water pressure squeezing folds of the suit together, making the suit smaller, which then squeezes you.

Adding air relaxes the folds and loosens the suit.

That's why drysuit "hickeys" are always where the creases were.

Terry

Drysuit squeeze is not caused by the water pressure squeezing the folds of the suit together. It is caused by the increased water pressure on the outside of the suit and a lower amount of pressure within the suit. Think of your ears and how you equalize while descending...it's the same principle. It is Impossible to make the drysuit smaller underwater (neoprene air pockets compress making the neoprene thinner) because a drysuit is made from an unpliable material. It is possible to compress the suits thickness (due to air in the material), but you cannot change the length and width of the material. (does a steel bar get smaller underwater, no, neither does a cotton shirt). The hickeys are always where the creases are in a drysuit because they are an uneven surface being pressed against the smooth surface of your skin. (ever fall asleep on the couch and had the fabric imprint on your face?)

-Kstnbike

 

[Thalassamania]

Drysuit squeeze is not caused by the water pressure squeezing the folds of the suit together. It is caused by the increased water pressure on the outside of the suit and a lower amount of pressure within the suit. Think of your ears and how you equalize while descending...it's the same principle. It is Impossible to make the drysuit smaller underwater (neoprene air pockets compress making the neoprene thinner) because a drysuit is made from an unpliable material. It is possible to compress the suits thickness (due to air in the material), but you cannot change the length and width of the material. (does a steel bar get smaller underwater, no, neither does a cotton shirt). The hickeys are always where the creases are in a drysuit because they are an uneven surface being pressed against the smooth surface of your skin. (ever fall asleep on the couch and had the fabric imprint on your face?)

-Kstnbike

While that's an interesting theory. Time for a little Socratic dialectic: how do you then explain dry suit squeeze whilst wearing a neoprene dry suit?

 

[H2Andy]

Drysuit squeeze is similar to mask squeeze, if you don't add air it hurts. If your mask is full of water, no problem ... right?

i wouldn't know ... my mask has never been full of water

 

[Thalassamania]

i wouldn't know ... my mask has never been full of water

For the love of pasta Andy, get with the program.

 

[Tigerman]

Still makes no sense.

Picture a 1 square inch tube pressed against your skin. Now pump it full to 50psi with air, water, bananas, oil, or jelly. The pressure exerted against your skin is going to be 50psi in all cases.

If you let half the air out of the dry suit, the air pressure inside won't be halved, the volume will be halved because the water will press the suit in until the pressure is equalized.
...

Do you drive a car?
If you do, you have probably filled air in your tires?
When you fill air in the tires of your car, what happens? The preassure in the tires increase. Why? Because you fill more air into a CLOSED container.

The drysuit is basically a tire. Its a closed container of fixed volume.
As you know, air will expand and compress when you change depths and that is why you need to fill air into your bc when going down and dump when going back up.
Your bc is another item with same properties as the mentioned tire.

The wetsuit however, is a punctured tire or bc..
It lets water flow through the suit, equalizing the preassure automatically, rather than you having to do it manually, by letting more air into your suit..