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

[Thalassamania]

Calm my young PADIwan and NACDwan. Empty or full half the glass is?

 

[Meng_Tze]

I think it is the air pulling the suit onto your body

When you open the door to your closet:

Is light going in or is dark running out?

 

[ClayJar]

When you open the door to your closet:

Is light going in or is dark running out?

Neither. I turn on the 60-watt dark sucker before I go in. (Well, except that one time when the fuse released the magic smoke and stopped up the dark sucker.)

(I think missing lunch might not have been a great idea, eh?)

 

[markr]

One more time. This is Boyle's law in action. You are inside a balloon. Fill a balloon with water. Increase the external pressure. The balloon stays the same size. Fill a balloon with air. Increase the external pressure. The balloon shrinks. You are inside the balloon. The balloon squeezes you because the volume of gas inside it is shrinking.

You would get squeeze in a chamber ride if you were in a drysuit, yes.

If you measure the pressure inside the balloon when it's at 100' you will get the same reading, approximately 59 psi, irregardless of the balloon containing water or air. At 100' the pressure on your skin is going to be 59 psi in a drysuit, 59 psi in a wetsuit, 59 psi stark naked. The only way to change the pressure would be to wear a hard suit or use a submarine.

 

[Thalassamania]

Reminds me of the write only memory I once had that was controlled by a DED (Dark Emitting Diode).

 

[Green_Manelishi]

My wet suit squeezes me much more than my drysuit squeezes me. Oh, wait, that's topside ...

 

[markr]

It is not the diver that's getting squeezed. It is the air space surrounding the diver.

When the air decreases volume, it pulls on what's around it to take up that volume. i.e. the material and water outside and your skin and tissue inside.

The discomfort associated with squeeze is not pushing in. It is pulling out and applying shear forces on your skin.

In a fluid-filled wet suit, there is nothing outside your skin to shrink. Thus, your skin is not pulled and you don't feel discomfort.

The air is decreasing in volume because it is being compressed due to being at a higher pressure. The decreasing volume doesn't magically create a low pressure area against your skin, it creates a pressure against your skin equal to the pressure of the compressed air.

 

[markr]

Damn, this is getting funny...

...and sad.

This may be the most accurate comment in this thread.

 

[Soggy]

If you measure the pressure inside the balloon when it's at 100' you will get the same reading, approximately 59 psi, irregardless of the balloon containing water or air. At 100' the pressure on your skin is going to be 59 psi in a drysuit, 59 psi in a wetsuit, 59 psi stark naked. The only way to change the pressure would be to wear a hard suit or use a submarine.

I didn't say the pressure inside the balloon would be different. I said the volume inside the balloon would be different. You are inside the balloon. The balloon shrinks to fit the volume of gas inside. You can't shrink. You get squished.

 

[ClayJar]

Actually, if it were a frictionless, infinitely stretchable (I don't use the term "elastic" here, as that has a distinct and well-defined meaning in physics) drysuit, it wouldn't matter that the volume of air between your skin and the suit had changed. The suit would be squeeze-proof, as only the thickness of the insulating air would be affected. (This is assuming your undergarments are equally well made, of course, but the physics of fleece under compression are not within the scope of this post.)

The reason the decreasing volume of air *does* matter is that the suit is certainly not frictionless and infinitely stretchable. As a result, you get ridges and pinch points and all those material-related squeeze effects.