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

[dfx]

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.

No, the best warmth would be a dry dry suit, because air is a good insulator and water isn't. However, when you're comparing wet suits, then you're correct: thicker neoprene = better; less water exchange = better. That's all there is to it, at least when it comes to the long term.

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.

Unless you're talking a completely flooded dry suit, this is an entirely different matter. Water evaporates in air and consumes heat when doing so. It makes you cold and will continue doing so until all water is evaporated (which, with a leak, will never happen).

With a completely flooded dry suit, it's only a matter of (uncomfortable) time until your body managed to warm up the water inside the suit. Afterwards (if you manage to survive that, as water takes an enormous amount of energy to warm up) it should be comfortably warm.

 

[manni-yunk]

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.

I think your comparison of warmth in a flooded drysuit, which is cut and formed to behave and perform differently than a proper wetsuit is fatally flawed.

 

[Panama Jones]

Regardless of which camp your in, IMO the arguments are useless. See, everyone will agree that a glove-like fit tight to the skin is the most important aspect of wetsuit use. So, if this is the case, the amount of water trapped between suit and the skin amounts to nothing more than dampness. And we're arguing insulating factors.

 

[Storker]

Speaking as a marine biologist, water is superb for heat storage. It's well known that critters with a low surface:area volume ration but high overall fluid volume are optimal for reducing heat loss. Ergo, if John Doe *seals in* some water in his suit, he's effectively turning himself into a fatter and better insulated manatee.Which is exactly what was posted here:

Speaking as an engineer, let's run the numbers for a real-life "John Doe" and see if it makes a difference for a SCUBA diver. I'll take an example which I know fairly well. i.e. myself.

My bodyweight is somewhere between 75 and 80kg. The specific heat capacity of the human body is 3470 J/kg·K, so my body's heat capacity is around 270 kJ/K. This summer I dived in an ill-fitting wetsuit providing a fairly large volume of water (more or less) trapped close to my skin and contributing to my overall thermal capacity. I'd estimate the amount of water pouring out of my suit when I took off my booties to about 2 liters, maximum 3. With water's heat capacity of 4200 J/kg·K, that water had a heat capacity of between 8.5 and 12.5 kJ/K. That's 3-5% of my body's total heat capacity.

In other words, the additional heat capacity of the water trapped under my wetsuit was close to negligible. And that was with an ill-fitting rental suit. I'd hazard the guess that it won't be much different for another John Doe.

 

[windapp]

First. It is not a myth. It is a misunderstood statement.

You cannot keep water out of a wet suit. If you could, you would get some pretty painful squeezes. A wet suit (including semi-dry) is designed to prevent additional water from circulating once water has initially penetrated the suit. It does this because, once a very thin layer is formed, it won't flow easily. This is why a good wet suit, if donned dry, will be initially very cold in cold water, and then warm up. The water that penetrated the suit has to warm to your body temperature. If the layer of water were to be thick enough, it would flow easily, and the insulation of the suit would be reduced by the fact that new, cold water, is continually being introduced.

The air bubbles in the neoprene provide the majority of insulation for your wet suit with the neoprene itself also providing some of the insulation.

 

[dfx]

Regardless of which camp your in, IMO the arguments are useless. See, everyone will agree that a glove-like fit tight to the skin is the most important aspect of wetsuit use.

No, not really, it's only one of the important aspects. The other one is neoprene thickness. You need a good fit to prevent water exchange with the surroundings (because the less water is trapped inside your suit, the less can be exchanged). Once that is achieved, the warmth determining factor becomes only the insulating capabilities of the neoprene, which depend on thickness and material.

 

[Panama Jones]

No, not really, it's only one of the important aspects. The other one is neoprene thickness. You need a good fit to prevent water exchange with the surroundings (because the less water is trapped inside your suit, the less can be exchanged). Once that is achieved, the warmth determining factor becomes only the insulating capabilities of the neoprene, which depend on thickness and material.

Sorry...of course you can't discount thickness..didn't mean to imply otherwise

 

[RJP]

Speaking as an engineer, let's run the numbers for a real-life "John Doe" and see if it makes a difference for a SCUBA diver. I'll take an example which I know fairly well. i.e. myself.

My bodyweight is somewhere between 75 and 80kg. The specific heat capacity of the human body is 3470 J/kg·K, so my body's heat capacity is around 270 kJ/K. This summer I dived in an ill-fitting wetsuit providing a fairly large volume of water (more or less) trapped close to my skin and contributing to my overall thermal capacity. I'd estimate the amount of water pouring out of my suit when I took off my booties to about 2 liters, maximum 3. With water's heat capacity of 4200 J/kg·K, that water had a heat capacity of between 8.5 and 12.5 kJ/K. That's 3-5% of my body's total heat capacity.

In other words, the additional heat capacity of the water trapped under my wetsuit was close to negligible. And that was with an ill-fitting rental suit. I'd hazard the guess that it won't be much different for another John Doe.

Very clearly articulated, but I have no idea what it says.

Are you sure you're an engineer? Sounds more like a mathematician.

 

[Storker]

Very clearly articulated, but I have no idea what it says.

archman claimed that the heat capacity - the ability to store heat - of the extra water inside your wetsuit gave you an extra reservoir of stored heat.

I did the math and found that for my example, that reservoir is so small that it doesn't make any difference.

Clearer now?

Are you sure you're an engineer? Sounds more like a mathematician.

An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics, and ingenuity to develop solutions for technical problems.

Link

 

[dumpsterDiver]

archman claimed that the heat capacity - the ability to store heat - of the extra water inside your wetsuit gave you an extra reservoir of stored heat.

I did the math and found that for my example, that reservoir is so small that it doesn't make any difference.

Clearer now?



Link

If your body has to heat the water that leaks into a suit, then it is a drain of heat, not a source of it. Your calculation, assumes that the water entering in the suit is 98,6 degrees, right?