Dive ops handling wetsuits

[dfx]

Next time you're diving ask somebody if you can lick their wet suit, on the inside around the crotch region if you think a wetsuit is so different than a diaper. I'm betting you won't.

You're right I won't, but not because of any potential pee. It's because ocean/lake water is neither clean nor potable.

Neoprene is designed to absorb water too! That is why wetsuits work. They capture and absorbe water into the layers of porous rubber and your body heat warms it up.

Nonsense. Neoprene is 100% water proof, it doesn't absorb anything. The only part of a wetsuit that absorbs water is the fabric protecting the neoprene, and that's not a whole lot.

 

[DjDiverDan]

Nonsense. Neoprene is 100% water proof, it doesn't absorb anything. The only part of a wetsuit that absorbs water is the fabric protecting the neoprene, and that's not a whole lot.

While the part about neoprene being 100% waterproof is technically accurate, it is highly misleading. A sponge is technically waterproof, too, but it's not the cell structure of the sponge that absorbs water - it's all the tiny little nicks, crannies, and voids created by the physical structure of the sponge. Many materials, including rubber and most plastics, are technically waterproof in that they do not absorb water a the molecular level. But they can easily be formed into shapes which absorb water by creating lots of little voids into which water can migrate. When Neoprene is is formed into a foam of the type used to make wetsuits, it looks exactly like a sponge on a microscopic level, and there is a LOT of water that fills into the nooks, crannies, and interstitial spaces and voids within the neoprene foam. AggieDiver had it exactly right on the warming properties of a wet suit - your body heats up the water trapped within the neoprene foam, and water is VERY efficient at holding that heat and reradiating it back to your body.

 

[dfx]

While the part about neoprene being 100% waterproof is technically accurate, it is highly misleading. A sponge is technically waterproof, too, but it's not the cell structure of the sponge that absorbs water - it's all the tiny little nicks, crannies, and voids created by the physical structure of the sponge. Many materials, including rubber and most plastics, are technically waterproof in that they do not absorb water a the molecular level. But they can easily be formed into shapes which absorb water by creating lots of little voids into which water can migrate. When Neoprene is is formed into a foam of the type used to make wetsuits, it looks exactly like a sponge on a microscopic level, and there is a LOT of water that fills into the nooks, crannies, and interstitial spaces and voids within the neoprene foam. AggieDiver had it exactly right on the warming properties of a wet suit - your body heats up the water trapped within the neoprene foam, and water is VERY efficient at holding that heat and reradiating it back to your body.

Again, nonsense. Please review http://www.scubaboard.com/forums/ba...-wetsuit-help-hurt-myth-busted-confirmed.html
Trapped water = bad. Trapped air/other gas = good.
And no, a sponge isn't water proof.

 

[Mike]

You're right I won't, but not because of any potential pee. It's because ocean/lake water is neither clean nor potable.

Good to know. So you're okay with licking my wet suit if I clean it first with bleach then pee in it. I want to get this on Youtube.

 

[dfx]

Good to know. So you're okay with licking my wet suit if I clean it first with bleach then pee in it. I want to get this on Youtube.

Bleach? No thanks. But if you were swimming in a large body of water with a virtually unlimited amount of clean tap/potable water, then yeah I would.

 

[DjDiverDan]

Again, nonsense. Please review http://www.scubaboard.com/forums/ba...-wetsuit-help-hurt-myth-busted-confirmed.html
Trapped water = bad. Trapped air/other gas = good.
And no, a sponge isn't water proof.

That thread is useless, as it asks the wrong question. It specifically poses the question as: "will a person stay warmer in a completely dry wetsuit or in a wetsuit with an unchanging thin layer of water." The answer to that question ought to be obvious. Because water is a much more efficient thermal conductor than air, you will ALWAYS be warmer in a drysuit than in a wetsuit. Putting even a thin layer of air between your body (at 98.6 degrees Farenheit) and water at 78 degrees Farenheit will significantly slow the loss of body heat through conduction and convection. There are three methods of heat transfer - conduction, convection, and radiation. By the Second Law of Thermodynamics, when you have two adjacent closed systems at different energy levels, both will seek equilibrium by equalizing the energy level. In this case, the body at 98.6 deg. and the water at 78 deg. will seek equilibrium by transfering heat from the higher energy level to the lower - temperature being simply a means of measuring energy.

The RIGHT questions to ask (unless of course you are stating that everyone in Cozumel ought to be diving with a dry suit) are: (1) Is a wetsuit better at preserving body heat than diving with no temperature protection? and (2) If the answer to Question (1) is YES, By what physical mechanism does a wetsuit perform this function.

Simple experience ought to tell you that a wetsuit does improve a swimmer's ability to preserve body heat. If you don't believe it, try doing multiple consecutive days of multiple dives in Cozumel in just a swimsuit. There are several mechanisms which explain how a wetsuit slows loss of body heat. First, there are a lot of voids in a wetsuit that do not fill up with water - think of these as closed bubbles where there is no access for seawater to enter. The existence of these closed bubbles is proven by the fact that wetsuits are compressible at depth. Only gases can compress under pressure; water is not capable of being compressed, so if ALL voids in a neoprene wetsuit filled with water, there would be no compression. These air bubbles provide exactly the same insulating property, on a microscopic level, that a drysuit provides, i.e., they slow conduction of heat from your body to the water. But this mechanism is affected by the size of the bubbles and the density of the air within them. At depth, as the air bubbles are compressed and the air within the bubbles increases in density, the insulation properties of these bubbles is reduced. You get the same effect in a drysuit at depth unless you add more air to maintain the size of the air pocket between your body and the water. The second mechanism by which the wetsuit helps maintain warmth is related to the water trapped within the accessible voids in the wetsuit - i.e., the water which is absorbed into the open structures of the neoprene foam. The rate at which heat is conducted between two systems is a function of both the heat absorption ability of the substances and the temperature differential. Water is much more efficient than air at absorbing heat from your body, but it's also very efficient at holding that heat. So,the water trapped in the structure of the Neoprene absorbs body heat, which warms up that water. Now, instead of the body at 98.6 deg. F. being directly adjacent to seawater at 78 deg. F., there is a thin layer of trapped water at an intermediate temperature - say 88 degrees F. That layer, trapped in the neoprene, is conducting heat away from your body, but at a SLOWER RATE than would be the case if the water were 78 deg., AND it is conducting that heat into the open ocean water (which is still at 78 deg. F.), but again at a SLOWER RATE than your body would conduct the heat, because of the smaller temperature differential. The third, and most important, mechanism by which wetsuits work is by interfering with convection. If you had no trapped layer of water between you and the ocean, your body would still warm up the water immediately adjacent to it through conduction, but the warmed water would immediately be swept away and replaced by colder water. Convection is what explains the "wind chill factor" in winter. In high winds, the air immediately adjacent to your body which you heat up through conduction of body heat is immediately swept away from you, and replaced with air that was just as cold as before - it speeds up loss of body heat through conduction (and radiation, but the effect of radiation on this example is de minimus). By trapping the water in a thin layer between your skin and the wetsuit, AND within the open pores in a neoprene wetsuit, the wetsuit interferes with convection so that you retain the benefits of the water which you warmed up to above the level of your surroundings, slowing conduction of heat away from you. Which is why a poorly fitting wetsuit provides so little protection; if it allows water to freely flow between your skin and the wetsuit, the water which you warmed up through body heat is quickly swept away, and you lose most of the benefts of the slower conduction provided by the layer of warmer water.

And next time you call "Nonsense" on something, you might want to consider the fact that you are apparently completely clueless about both the physical structure of Neoprene foam AND about the Laws of Thermodynamics and Fluid Mechanics. As the philosopher once stated, "Better to keep your mouth shut and be thought dull, than to open your mouth and remove all doubt."

 

[kixy1]

The thread that won't die! (even if you pee on it)

 

[Basscat]

"The thread that won't die! (even if you pee on it)"

And it has become even more absurd than the Monty Python sketch, "I'm not dead yet!"
Some of us pee in our suits, some of us don't. The ocean is probably big enough to handle it. Some dive ops wash wet suits, some don't, make your choice, and enjoy your dives. Sheesh....

 

[dfx]

That thread is useless, as it asks the wrong question.

Not at all. The mechanism which you claim helps to preserve heat is exactly what the myth is about. Specifically:

The second mechanism by which the wetsuit helps maintain warmth is related to the water trapped within the accessible voids in the wetsuit - i.e., the water which is absorbed into the open structures of the neoprene foam. The rate at which heat is conducted between two systems is a function of both the heat absorption ability of the substances and the temperature differential. Water is much more efficient than air at absorbing heat from your body, but it's also very efficient at holding that heat. So,the water trapped in the structure of the Neoprene absorbs body heat, which warms up that water. Now, instead of the body at 98.6 deg. F. being directly adjacent to seawater at 78 deg. F., there is a thin layer of trapped water at an intermediate temperature - say 88 degrees F. That layer, trapped in the neoprene, is conducting heat away from your body, but at a SLOWER RATE than would be the case if the water were 78 deg., AND it is conducting that heat into the open ocean water (which is still at 78 deg. F.), but again at a SLOWER RATE than your body would conduct the heat, because of the smaller temperature differential.

This is exactly one of the points being discussed in the thread. This mechanism doesn't exist. If the neoprene was soaked with water, it would conduct heat at the same rate as water itself, which is very quickly. You'd get cold as quickly as without any wetsuit. Or as quickly as wearing a woolen sweater in the water, which has exactly that property. You should really raise that point in the other thread for more detailed discussion.

Something to think about: if neoprene was able to absorb water as you claim, there had to be a way for the water to enter into the neoprene. As such, the water would also be able to pass through the neoprene, given enough time. Take the thinnest wetsuit you can find (1mm?) and form a pocket or a bag with it. Fill it with water. See how long it takes until water drips out the bottom. Hint: it never will. How do you think neoprene drysuits work?

The third, and most important, mechanism by which wetsuits work is by interfering with convection. If you had no trapped layer of water between you and the ocean, your body would still warm up the water immediately adjacent to it through conduction, but the warmed water would immediately be swept away and replaced by colder water. Convection is what explains the "wind chill factor" in winter. In high winds, the air immediately adjacent to your body which you heat up through conduction of body heat is immediately swept away from you, and replaced with air that was just as cold as before - it speeds up loss of body heat through conduction (and radiation, but the effect of radiation on this example is de minimus). By trapping the water in a thin layer between your skin and the wetsuit, AND within the open pores in a neoprene wetsuit, the wetsuit interferes with convection so that you retain the benefits of the water which you warmed up to above the level of your surroundings, slowing conduction of heat away from you. Which is why a poorly fitting wetsuit provides so little protection; if it allows water to freely flow between your skin and the wetsuit, the water which you warmed up through body heat is quickly swept away, and you lose most of the benefts of the slower conduction provided by the layer of warmer water.

Yes, except for the part with the pores and stuff. A rubber or latex suit does the same thing. In fact, you want something that specifically does not absorb any water, because if it does, then that means the absorbed water has to be replaced with water from the surroundings, which would be cold. And as above, if neoprene was able to absorb water, it would also allow water to pass through it, totally negating the effect you just described.

And next time you call "Nonsense" on something, you might want to consider the fact that you are apparently completely clueless about both the physical structure of Neoprene foam AND about the Laws of Thermodynamics and Fluid Mechanics. As the philosopher once stated, "Better to keep your mouth shut and be thought dull, than to open your mouth and remove all doubt."

Look who's talking.

 

[cvchief]

I do not work with nursing home residents so can not speak to its frequency in this population but I doubt you will find many diving, in wetsuits or otherwise. .)

Well.... Go to palancar pier. Examine the dive boats. Often half the boat looks like escapees from the geriatric ward....