Cold water & wet suit

[broncobowsher]

This is the scuba version of homeopathy. The "layer of water keeps you warmer" is totally wrong even if it's repeated over and over with increasingly technical terms.

Water has no insulating properties whatsoever and a wetsuit would be warmer still if that layer of water didn't exist. Such a suit does exist and it's called an uncrushed neoprene drysuit. For wetsuits, the use of neoprene with a slick skin side and as tightly fitting as possible are all ways to decrease that supposedly 'insulating' (/s) layer of water and increase the warmth factor to the extent you can with a given thickness of neoprene - the less water between you and the suit the better.

Correct. Water is a great conductor, horrible insulator.
What I mentioned above is trying to keep a small quantity and not exchange it for more cold water. You are taking a warm water bath, with a very small amount of water that your body has heated up.

 

[rjack321]

Where are you reading that water "has no insulating properties whatsoever?" Water can absorb and retain heat and I can't find anything to the contrary online.

The only source of heat is your body. Your body LOST heat to warm up that layer of water, it's never going to get that heat back. Your body will continue to try and keep that layer warm whether that energy is lost to flushing (really bad) or through the neoprene (slower than flushing but still gone).

Water is a really, really bad insulator, one of the worst possible. The only liquids which are even worse insulators are things like mercury or gallium.

Thermal conductivity of water 0.6 W/m2/k
Thermal conductivity of air 0.02 w/m2/K

List of thermal conductivities - Wikipedia

en.wikipedia.org

millimeter to millimeter, air (the bubbles in the neoprene) is about ~30x less conductive than that layer of water.

 

[JuLe]

@JuLe is from Finland, they have different blood than the rest of Homo sapiens. I could never do 4C for 60mins in a wetsuit either

To be honest, most of us here dive dry. I was one of the few exceptions and like I wrote earlier, I wimped out and bought me nice drysuit just a week ago..

 

[rick00001967]

This is the scuba version of homeopathy. The "layer of water keeps you warmer" is totally wrong even if it's repeated over and over with increasingly technical terms.

Water has no insulating properties whatsoever and a wetsuit would be warmer still if that layer of water didn't exist. Such a suit does exist and it's called an uncrushed neoprene drysuit. For wetsuits, the use of neoprene with a slick skin side and as tightly fitting as possible are all ways to decrease that supposedly 'insulating' (/s) layer of water and increase the warmth factor to the extent you can with a given thickness of neoprene - the less water between you and the suit the better.

finally someone who gets it.

 

[rick00001967]

Where are you reading that water "has no insulating properties whatsoever?" Water can absorb and retain heat and I can't find anything to the contrary online.

technically we cannot say that "warm water" has no insulating properties whatsoever". but you are missing the point.
air is a better insulator. and obviously in this case, we are using neoprene as the insulator which works well.
if the suit lets in water, your body has to provide the heat energy to warm that water. that decreases your own bodies heat and energy stores. pretty simple.
then as that water cools, and more surrounding water creeps in and out, you have to use even more body heat and energy to reheat the new water. not very efficient right?
this is why many people (including me in the past) have been diving on a site where someone will pour very warm water into your suit to start the dive.
what does this do? it obviously provides a temporary heat source and means you are not expending your own body heat and energy to heat that already warm water.
but it does not change the fact that surrounding cold water can still enter the suit and flush out the warm. so now you have to use your own body heat and energy to reheat that new water. is it more efficient adding warm water to start the dive? of course it is.
but none of this is as efficient as having zero water in your suit. period. thats why they invented the drysuit.
the simple question is......which is warmer.....a very wet wet suit, or a drier wet suit? and if anyone thinks a wet wetsuit is warmer they need to give their head a shake. the drier the better.
or
which is warmer.....a 7mm west suit, or a 7mm dry suit? they are both made using the same insulator right? but obviously the 7mm dry suit would be more efficient at keeping someone warm.
both can work well depending on the circumstances but there simply is no valid argument that can change the fact that being dry beats being wet.

 

[34109411]

i like the debate

 

[jellycatsdad]

I’ve been diving a Henderson Aqualock 7mm with a 7/5mm hooded vest and a dive skin underneath it. Seems to work fine in NorCal waters that are usually in the mid-50s. Compared to the rental suits I had, I’m actually comfy in it.

I’ll go dry… eventually just because I want better control of my buoyancy but with a more complex setup. And to stay a bit more warm.

 

[MacDuyver]

everyone has different opinions on cold water diving.

clearly a drysuit is the best option but many people where i live have gone cold water diving with one piece 7mm wet suits. they even ice dive. you will never see me doing that again. lol

i personally do not know anyone who dives a two piece suit anymore. i did when i first started diving. it was the worst purchase i ever made. but thats just my opinion. modern suits are much better now.

we have a bunch of divers here that got into using semi dry's. they liked them. i believe the thickest i have seen is 8mm? couple that with a well fitted 7 to 10mm hood, good boots with possibly merino wool socks inside, and maybe some three finger gloves that seal properly at the wrist, and many could tolerate quite intolerable conditions.

thin merino wool tops and bottoms can also be worn under the suit for added warmth.

just a suggestion in case the op had never considered one

Dove in the Puget Sound several times in a 7mm with a hood. I never thought it was THAT bad.

Recently I got a drysuit.


After 2 dives in my drysuit, all I can say in regards to the cold is f[CENSORED]k a wetsuit.

 

[rick00001967]

Dove in the Puget Sound several times in a 7mm with a hood. I never thought it was THAT bad.

Recently I got a drysuit.


After 2 dives in my drysuit, all I can say in regards to the cold is f[CENSORED]k a wetsuit.

and the other thing many do not consider is the benefit of when you are changing on shore or on a boat in less than idea weather conditions.

it is a huge plus to be able to easily get out of a dry suit and be dry and warm vs. fighting to get out of your wet suit and then being wet and cold. especially if it is raining or even snowing. brrrrr. no thanks. been there. done that.

 

[Chavodel8en]

and the other thing many do not consider is the benefit of when you are changing on shore or on a boat in less than idea weather conditions.

it is a huge plus to be able to easily get out of a dry suit and be dry and warm vs. fighting to get out of your wet suit and then being wet and cold. especially if it is raining or even snowing. brrrrr. no thanks. been there. done that.

I've dove for 20 yrs in Monterey/Carmel in a wetsuit and I am fine underwater. I dont feel the need to get a drysuit.

However, I must admit, that when the air temperature is very cold, Im not diving. I will freeze changing in/out. But around here, thats basically just late January & February. I've dove into January, on relatively warm days.