Does water in a wetsuit help or hurt. A myth to be BUSTED or CONFIRMED

[eelnoraa]

Water is definitely NOT what keep you warm in a wetsuit. If so, a 3mm and a 7mm won't make any difference. And we know that isn't true

Neoprrene is what keep you warm in wetsuit. But water getting into a wetsuit is inevitable. The key here is no water exchange. Once water get in for the first time, it should be trapped inside the suit, you body warm up that small amount of water, but then it is the neoprene that insulate the outside cold water from the inside water, which has been warmed up by your body. A badly fit wetsuit with lots of water exchange is a cold wetsuit

 

[dumpsterDiver]

Water is definitely NOT what keep you warm in a wetsuit. If so, a 3mm and a 7mm won't make any difference. And we know that isn't true

Neoprrene is what keep you warm in wetsuit. But water getting into a wetsuit is inevitable. The key here is no water exchange. Once water get in for the first time, it should be trapped inside the suit, you body warm up that small amount of water, but then it is the neoprene that insulate the outside cold water from the inside water, which has been warmed up by your body. A badly fit wetsuit with lots of water exchange is a cold wetsuit

Exactly! Now that wasn't hard to understand was it?

 

[spectrum]

Thanks Pete. This is response is helpful in moving us forward. Could you suggest a good way of telling instructors how to explain water in wetsuits to students which could replace the original quote of "With a wet suit, a thin layer of water between the diver’s body and the suit serves as insulation."

I would tell them to read this feature, especially the "Checking the Fit" subtopic.

If instructors would only teach the physics they understand life would be better.

Pete

 

[Panama Jones]

I never did subscribe to the "thin layer" theory. But here's a thought. I dive a Bare Velocity 7mm that fits me like a glove. In cold water, it's the warmest wetsuit I ever dove. I don't think it's sold as a semi dry but it has seal around calves, forearms and neck. When I get out of it after a dive, I always point out to my buddy that the easy glide layer inside, or whatever its called, is "DRY (in most places). So much for the thin layer theory.

 

[RJP]

As I read it, it is saying that water is not good, and that the best you could do, in what is later called "a very good suit," is minimize the amount of water in so that the problem of heat loss through water is minimized.

Sounds like the vast majority of DRY suits I hear people complaining about on SB...

Even the best drysuits are Dry Until Immersed!

:d

 

[TSandM]

There is something appealing about archman's analysis, except for the fact that it doesn't hold up in real life very well.

By that theory, the best warmth should be a flooded neoprene dry suit, by virtue of the fact that water EXCHANGE in a dry suit with a small hole in it is minimal, and the suit still has insulating capacity. But I can tell you that being wet in a dry suit is nowhere near as warm as being dry in a dry suit, having had significant experience with both states.

I suspect that, since neoprene is not a perfect insulator at all and the rate of heat loss to the water is greater than the body's ability to generate heat without shivering (and sometimes even with), that the immediate heat loss to the water layer is simply permitting the heat which is going to be lost during the dive to be greater initially than it would be if there were no water present. The water has been warmed, but the body has been cooled by the same amount of energy -- and yes, the body is generating heat, but clearly, as we all know, it is NOT generating it at the rate at which it is being removed, water or not.

 

[crosshairs]

I never did subscribe to the "thin layer" theory. But here's a thought. I dive a Bare Velocity 7mm that fits me like a glove. In cold water, it's the warmest wetsuit I ever dove. I don't think it's sold as a semi dry but it has seal around calves, forearms and neck. When I get out of it after a dive, I always point out to my buddy that the easy glide layer inside, or whatever its called, is "DRY (in most places). So much for the thin layer theory.

I dive a Henderson Aqualock 7mil....also a wet suit with seals on the calves, forearms and neck made to work with their boots, gloves and hood....90% of the time after a dive the suit is dry as a bone inside...on the occasion that I do get some water flushed it's still warm, but not as much....

 

[Bob DBF]

We really need some science here. Has anyone done or know someone that has done experiments that would lead us to a resolution. Even though it SEEMS logical that a person would stay warmer in a completely dry wetsuit or in a wetsuit with an unchanging thin layer of water; some of the experts we talked with say that may not be the case.

dfx had in in post 6.

Neopreme is an insulator, water is a conductor, and the rest is a story to sell whatever thermal protection you have in stock.



Bob
-------------------
I may be old, but I'm not dead yet.

 

[archman]

This is thermodynamics not some silly biology class where you misapply terms to suit your argument.

On scubaboard, it is the privilege of readers to discount the professional expertise requested by other posters. I have been very careful to not state any "opinions" on this thread, but the known scientific principles as the community understands them. Terms used are all accurate and taken from the literature, except "insulator" which I have retained in quotes. The recreational scuba website links provided are using the term in a relative rather than absolute sense (relative to air, specifically), which seems to make up a great deal of the current confusion.

If one is under the impression that a biologist is not competent regarding these questions, you may inquire with a chemist or a physicist, and you will get similar sounding answers, since the foundational properties for molecular water are universal and basic between the disciplines. Heck, you can wikipedia them. Metabolic heat transfer in living organisms has been studied since the 1950's. The physiologist crowd got the gist of it before 1980.

Thermodynamics and Biology are not mutually exclusive. The former is embedded within the latter, or vice-versa depending on your perspective.

I apologize for commenting in this thread, I misunderstood the OP's request for professional information, and will sign off here. I can be pm'd if people would like more information.There are fun demonstration experiments you can do yourself in the kitchen with little more than a couple of thermometers and some plastic baggies.

 

[billt4sf]

I suspect that, since neoprene is not a perfect insulator at all and the rate of heat loss to the water is greater than the body's ability to generate heat without shivering (and sometimes even with), that the immediate heat loss to the water layer is simply permitting the heat which is going to be lost during the dive to be greater initially than it would be if there were no water present. The water has been warmed, but the body has been cooled by the same amount of energy -- and yes, the body is generating heat, but clearly, as we all know, it is NOT generating it at the rate at which it is being removed, water or not.

most of the heat is being lost through convection, esp. in a poor-fitting wet suit, and also conduction between the two layers. Another factor is that the water has a greater surface area of contact than the neoprene, so more heat is lost directly to the water than to the neoprene.