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

[ReefHound]

Yes, the question is does it equalize pressure with more gas or by sucking your flesh into the lower pressure area, that's what squeeze is.

I'm choosing this as the explanation that makes the most sense. I've not been able to buy into the pressure-against-skin "squeeze" concept because 50psi water or 50psi fabric or 50psi air is all the same. But suction, pulling the skin outward, is something that can only happen with a compressible region surrounded by incompressible regions, e.g. a drysuit.

Since we are mostly water, it would seem the water pressure is transmitted through our body, meaning not only is the water pushing inward against the suit but our body fluids are pushing outward against our skin.

 

[Soggy]

ARGHHHHH

*unsubscribe*

 

[ClayJar]

You don't get bruises on your eyeballs, just where the mask frame pushes against you.

Have you ever seen someone surface with the grotesquely red eyes caused by extreme mask squeeze? I've not seen it myself, but if you'll admit hearsay into the thread, some instructing friends of mine have (and it totally freaked them out -- the diver did *not* get a card).

As for the rest of the thread, should I comment that I concur with the real physics, or should I ask when the movie will be out (as I'd previously believed only Hollywood could come up with misconceptions as great as some of these)?

 

[ReefHound]

Now bring just the suit down to 100 ft. The gas inside the suit will compess to roughly 1/4 the volume that it was on the surface. The suit, because it is made out of flexible fabric, will fold and crumple in order to accommodate the reduced volume inside.

Now, put yourself back in the suit. The fabric is going to exert pressure on your body because the gas inside has compressed and the suit wants to occupy a smaller volume.

Gotcha. Now tell me, at 100' depth:

If in a drysuit, what is the force in psi that the suit will be pressing against your skin?

If in a wetsuit, what is the force in psi that the water will be pressing against your skin?

 

[Thalassamania]

Gotcha. Now tell me, at 100' depth:

If in a drysuit, what is the force in psi that the suit will be pressing against your skin?

Only a few psi different than ambient (if that) where the suit has "trapped" a low pressure area.

If in a wetsuit, what is the force in psi that the water will be pressing against your skin?

Ambient since there is no trapped gas.

 

[Soggy]

Gotcha. Now tell me, at 100' depth:

If in a drysuit, what is the force in psi that the suit will be pressing against your skin?

If in a wetsuit, what is the force in psi that the water will be pressing against your skin?

It doesn't matter. It's the SUIT pushing against your skin causing the squeeze.

 

[ReefHound]

Have you ever seen someone surface with the grotesquely red eyes caused by extreme mask squeeze? I've not seen it myself, but if you'll admit hearsay into the thread, some instructing friends of mine have (and it totally freaked them out -- the diver did *not* get a card).

As for the rest of the thread, should I comment that I concur with the real physics, or should I ask when the movie will be out (as I'd previously believed only Hollywood could come up with misconceptions as great as some of these)?

I've never seen the red eyes (you mean the actual eyeballs, right?) but that would be consistent with Thal's explanation that the lower air pressure is sucking the skin outward. Maybe that's why some divers seem to have bulging eyes.

I definitely concur with the physics, whatever they may be. I don't think anyone is contending that there is no such thing as suit squeeze.

 

[ReefHound]

It doesn't matter. It's the SUIT pushing against your skin causing the squeeze.

It does matter, force is force. Define the force.

 

[Soggy]

It does matter, force is force. Define the force.

Boyle's law. I explained it above.

 

[erparamedic]

Good question.... great answers! I had never thought of wetsuit/drysuit sqeeze before. I feel enlightened.