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

[Tigerman]

The pressure is always the same inside and out- but if you don't add any additional gas to the inside of the drysuit, it shrink wraps you to compress the volume and equalize the pressure.

So to sum it up, the squeeze is simply the.. lets call it.. condom effect

 

[D_B]

The pressure is always the same inside and out- but if you don't add any additional gas to the inside of the drysuit, it shrink wraps you to compress the volume and equalize the pressure.

thank you DIE

It doesant matter, the difference is that with air, you have to add it to your suit to make up for the decreased volume of the air as it's compressed, the pressure inside is the same as outside, air or water.

 

[H2Andy]

ok, guys ... this is easy

the wetsuit is like a bottle of wine which you open ... and you pour... and eventually, everybody's happy ...

the drysuit is like a bottle of wine which you can't open ... and you try to use your fingers to pry the cork out, but you cant ... and you don't have a corckscrew because you can't find it under pressure ...

and your guests are like, say, is this party dry or what? when do we get some booze?

and you're like, i can't open the bottle!!!! i can't open the bottle!!!!

and you squeeze and squeeze the cork trying to get it out, but no good ...

that's basically it ... about as simple as i can make it

 

[do it easy]

thank you DIE

Busted- I didn't read the whole thread and I just quick replied to the last poster!

 

[D_B]

ok, guys ... this is easy

the wetsuit is like a bottle of wine which you open ... and you pour... and eventually, everybody's happy ...

the drysuit is like a bottle of wine which you can't open ... and you try to use your fingers to pry the cork out, but you cant ... and you don't have a corckscrew because you can't find it under pressure ...

and your guests are like, say, is this party dry or what? when do we get some booze?

and you're like, i can't open the bottle!!!! i can't open the bottle!!!!

and you squeeze and squeeze the cork trying to get it out, but no good ...

that's basically it ... about as simple as i can make it

OK, now I'm confused .. I think I'll go get a drink .. do I need to wear my wetsuit to get one?

 

[ReefHound]

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?

You don't get bruises on your eyeballs, just where the mask frame pushes against you. The pressure is not spread uniformly across the same surface area but concentrated in the small surface area where the frame mask contacts your face. Also, since the mask is rigid the air pressure inside is not equal to the water pressure outside.

 

[ReefHound]

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 drysuit is not a fixed volume, it would have to be a rigid shell for that to be true.

 

[rakkis]

A wet suit is made to comform to the shape of the body to miniminize water movement out of the suit. Because of that, any force outside of it is transduced evenly in an inwards direction.

A dry suit is made larger on purpose to provide space for air/undies.

So.. by design, the pressure on dry suit is not being applied evenly in a normal (the physics definition of normal) direction to the surface of your skin. Because of the extra flaps of material, the suit pinches and applies force irregularly and shears your skin. It pulls and tugs on it laterally more than a wet suit would.



= ouchie

 

[Tigerman]

The drysuit is not a fixed volume, it would have to be a rigid shell for that to be true.

Actually, it IS a fixed volume.. Its not like the fabric and surface area get smaller when it get squeezed together
Alas, the maximum volume of air (or water) it could hold is the same wether its fully inflated or fully deflated.

However, it feels smaller becaue the preassure difference force it to deform and squeeze your body.. The deformation will continue untill the remaining air pocket in the suit is the same pressure as the water pressure, but there is that blasted human body in the way..

HOWEVER, the key word in relation to squeeze, as i tried to emphasise in my first post is CLOSED container..
If the drysuit wasnt closed, it wouldnt be deforming due to the pressure changes and you wouldnt get sqeezed.
This is the case with a wetsuit.. Air flows through, automatically equalizing the pressure and you dont get the squeezy-feeling deformation of the container..

 

[rakkis]

since the mask is rigid the air pressure inside is not equal to the water pressure outside.

While the glass is rigid, the skirt isn't. Also, you have an open air way into the mask through your nostrils... which is primarily how the pressure inside the space equalizes with that outside.

The drysuit is not a fixed volume, it would have to be a rigid shell for that to be true.

Does the amount of air in a tied off balloon with no leaks change as I squish it around? There is no need for a container to be rigid for it to have constant volume.

What you mean to say is that a flexible container is subject to pressure changes; whereas a rigid one is not.

Pressure and volume, though related intimately in diving, are not the same concept.