Drysuit and squeeze question

[davehicks]

It was a hypothetical to illustrate an opinion that the more "air" space between the diver and the suit, the more the affect of the squeeze would be intensified. If a diver had closed cell neoprene drysuit custom made to fit tight.....(like a rash-guard fits) then there would be far less potential for squeeze than a looser fitting shell suit with a lofty undergarment.

Sigh. You just described a wetsuit. A drysuit is desiged to have an airspace as an insulator, so not snug.

You know how you create a sung fiting dry garment with no airspace in it? You suck or squeeze out all the air from it until it creates a vacuum and crushes and bruises your skin and you can barely move or (allegedly) breathe anymore. Circled right back around to the beginning didn't we?

 

[admikar]

you can't breathe anymore

I'm still not sure that's true.

 

[NW Dive Dawg]

It was a hypothetical to illustrate an opinion that the more "air" space between the diver and the suit, the more the affect of the squeeze would be intensified. If a diver had closed cell neoprene drysuit custom made to fit tight.....(like a rash-guard fits) then there would be far less potential for squeeze than a looser fitting shell suit with a lofty undergarment.

This is getting dumber. You just described a wetsuit. A drysuit is designed to have an airspace as an insulator, so not snug.

You know how you create a sung fiting dry garment with no airspace in it? You suck or squeeze out all the air from it until it creates a vacuum and crushes and bruises your skin and you can't breathe anymore. Circled right back around to the beginning didn't we?

Dumb would be having a closed mind and not being able to understand the differences in drysuits and how that can affect squeeze. In my avatar pic (from 20 years ago) I am wearing a Harveys Titanium 7MM NEOPRENE drysuit. I had this suit custom measured and made right from the factory in Kent, WA and it fit like a glove. Yes, the Neoprene suit did have some air space as do all drysuits......but FAR less than any shell suit with insulating undergarments. All I ever wore under the 7MM neoprene drysuit suit was a rash-guard to make it easier to don and also to help keep sweat off of the drysuit interior. The primary insulator in the suit was the 7mm of neoprene. Yes I did need to add some air to prevent all squeeze, but not nearly as much as needed in my shell suit..

 

[Seaweed Doc]

I hate the dry suit speciality, but I see some of you need it.

I've run more dry suit specialties than any other, and let me tell you there is a non-trivial fraction of the population that really need it. Usually by the second open water dive they're all at a point where they're not going to lose control and cork on every ascent, but not always.....

 

[MrVegas]

Tec divers have been dying from this for the past 30 years . . .

But this is really the question -- have tech divers actually been dying because their drysuits squeeze them so hard they can't breathe? Again, not trying to be difficult, but are you aware of a specific incident? At what depth did that happen?

The question here is not about whether drysuit squeeze is dangerous -- it is. The question is not about movement restriction, bruising, discomfort, etc. The question is about whether anyone can actually determine a precise depth at which an uninflated drysuit will prevent someone from drawing a breath. Could it happen within recreational depths (40m/130 ft)?

 

[Wibble]

But this is really the question -- have tech divers actually been dying because their drysuits squeeze them so hard they can't breathe? Again, not trying to be difficult, but are you aware of a specific incident? At what depth did that happen?

The question here is not about whether drysuit squeeze is dangerous -- it is. The question is not about movement restriction, bruising, discomfort, etc. The question is about whether anyone can actually determine a precise depth at which an uninflated drysuit will prevent someone from drawing a breath. Could it happen within recreational depths (40m/130 ft)?

It's about how inflexible the suit is which makes it uncomfortable.

If the person's breathing gas from a regulator then the inside of the chest will be at ambient pressure. The suit just tightens, making it uncomfortable, but it won't stop them from breathing.

As I said in a post above, I was at 40m/132ft in a membrane drysuit that wasn't connected to the drysuit inflate bottle. I'm writing this so could breathe. The bruises, caused by the folds in the suit when I moved my arm behind my back, went after a few days. The bruised ego took a little longer.

 

[Vicko]

But this is really the question -- have tech divers actually been dying because their drysuits squeeze them so hard they can't breathe? Again, not trying to be difficult, but are you aware of a specific incident? At what depth did that happen?

The question here is not about whether drysuit squeeze is dangerous -- it is. The question is not about movement restriction, bruising, discomfort, etc. The question is about whether anyone can actually determine a precise depth at which an uninflated drysuit will prevent someone from drawing a breath. Could it happen within recreational depths (40m/130 ft)?

If it restricts your movement enough that you can't add air or swim back up it does not have to kill you by constriction. A panicked diver goes trough the gas much quicker than someone would expect. And even if you can breathe it will create a lot of resistance that will prevent you from ventilating fully, leading to hypercapnia.

Go to your pantry and get a pack of vacuumed sealed food, rice, peanuts, coffee. Notice how hard it is while vacuumed and how impossible it is to loosen the contents without breaking the seal, and that's at around 0.005-0.01 bars.

 

[NW Dive Dawg]

If it restricts your movement enough that you can't add air or swim back up it does not have to kill you by constriction. A panicked diver goes trough the gas much quicker than someone would expect. And even if you can breathe it will create a lot of resistance that will prevent your from ventilating fully, leading to hypercapnia.

Go to your pantry and get a pack of vacuumed sealed food, rice, peanuts, coffee. Notice how hard it is while vacuumed and how impossible it is to loosen the contents without breaking the seal, and that's at around 0.005-0.01 bars.

Sure, but there is a lot of air between those types of foods when vacuum sealed. Try vacuum sealing a bag of water....which is primarily what we are composed of and talking about here. You'll find no change to the water. It will be pliable and move freely.

I still think it is not possible to generally determine a specific depth at which a dry-suit might compress enough to restrict breathing without taking into consideration the type of dry-suit and the amount of air between the suit and diver. Again, my custom fit 7mm Neoprene dry-suit had far less air space than my shell suit with a lofty undergarment......and that difference in air space affects the overall impact of squeeze.

 

[crofrog]

Sure, but there is a lot of air between those types of foods when vacuum sealed. Try vacuum sealing a bag of water....which is primarily what we are composed of and talking about here. You'll find no change to the water. It will be pliable and move freely.

I still think it is not possible to generally determine a specific depth at which a dry-suit might compress enough to restrict breathing without taking into consideration the type of dry-suit and the amount of air between the suit and diver. Again, my custom fit 7mm Neoprene dry-suit had far less air space than my shell suit with a lofty undergarment......and that difference in air space affects the overall impact of squeeze.

or a chunk of steak...

 

[Vicko]

Sure, but there is a lot of air between those types of foods when vacuum sealed. Try vacuum sealing a bag of water....which is primarily what we are composed of and talking about here. You'll find no change to the water. It will be pliable and move freely.

I still think it is not possible to generally determine a specific depth at which a dry-suit might compress enough to restrict breathing without taking into consideration the type of dry-suit and the amount of air between the suit and diver. Again, my custom fit 7mm Neoprene dry-suit had far less air space than my shell suit with a lofty undergarment......and that difference in air space affects the overall impact of squeeze.

Your body has nothing to do with the stiffness of the vacuumed suit, the air in the suit is the thing getting compressed and the resulting vacuum is the force keeping the suit stiff.
There's a lot of variables, the amount of air you started of with, the cut of the suit, the material it's made of, the depth of the dive.... But no matter the variables it's a thing that has happened to people. You have first hand accounts of people getting bruised in this thread and a reported fatality.