cold water exposure suit debate

[dumpsterDiver]

6' 9" and 295 lbs.. (with my fins and scuba gear on)

 

[Eric Sedletzky]

I have a 1/2" Rubatex G231N beaver tail two piece farmer john wetsuit (over one inch of material on my core!) with an attached hood that was going to be my urchin suit if the opportunity ever came up that I could do that job. I know people so it was a possibility. It cost me a thousand bucks, but it was the very last of that material on the west coast so I figured I'd buy a piece of history if nothing else. It's so warm that even in 45 degree water I get too hot and have to try and figure out a way to let cold water in or else I croak. It's a skin in suit and it was custom made so there are no leaks and no water really gets in to speak of. And since it's made of Rubatex I am warmer than drysuit divers many times, I hear them complain they're cold as I'm desparately trying to get my top off so I don't pass out from heat exhaustion after the dive. And then the steam is boiling off me on the boat, and this is in winter!

But for normal 53 degree diving I just use a freediving suit with no zippers, it's also skin-in. It's plenty warm down to 50-60 feet no problem.

The more you dive wet, the more your body will acclimate to the temps and you will burn calories more efficiently to stay warm. Your metabolism and cold tolerance will evolve and transition.

I absolutely abhor drysuits and would prefer not to even dive if I was stuck using one. I'll take my chances with a 7mm and steel tanks before you get me back into a drysuit. I would switch back to a poodle jacket before going back to a drysuit, that's how much I hate them.

But for you in your case, go with a drysuit.

 

[Johanan]

More air in the suit means you should be warmer during the beginning of the dive which increases your inert gas uptake and then you get progressively cooler during the dive which slows your off gassing during ascent putting you at increased risk for DCS. 20lbs of air is a significant amount of air and that can be a pretty significant difference in your thermal comfort and inert gas loading rates.

Interesting point. Must have missed this in Deco Procedures manual. I'll try to explore more on that, thanks.

 

[tbone1004]

Re: Don't dive cold when you don't have to. - PubMed - NCBI

New Product: Heat Controller
*using this one for the easy links to the articles and podcasts where they are talking about the studies that were done

 

[BoltSnap]

I am confused here, are you saying that staying cold is good and warm is bad from deco and Nitrogen absorption point of view??

 

[Hickdive]

A wetsuit that seems adequate now will probably not be so adequate when you are doing longer/deeper dives with less physical effort due to increased skill and experience.

In addition, as you have discovered, putting on a cold, wet, wetsuit for a second dive is less than fun whereas a drysuit is easier to wear during the SI or to put back on again. If you ever go on multi-day coldwater liveaboards getting back into that wetsuit becomes less and less appealing as the trip goes on and you start skipping dives. When that happens your cost-per-dive soars to the point that buying a drysuit in the first place, even though a higher initial spend, is actually the more economical option.

In the meantime, try staying in your wetsuit between dives but wearing a big parka or similar plus gloves and hat over it. Take your wet boots off and put on warm socks and dry boots but have a flask of warm (not boiling!) water to pour into the wet boots before putting them back on. The warm water trick works well with hoods and gloves too.

Also eat hot food and have hot drinks between dives. A cold sandwich and cold soft drink or water just don't cut it.

 

[Hickdive]

I am confused here, are you saying that staying cold is good and warm is bad from deco and Nitrogen absorption point of view??

The problem is being warm during the on-gassing phase of the dive but being cold during the off-gassing phase.

Cold reduces tissue perfusion, warmth increases it. Increased tissue perfusion during the on-gassing phase means a greater gas load, decreased tissue perfusion during the off-gassing phase means less efficient elimination of gas from tissues. Either be warm/warm for the whole dive or cold/warm, or even cold/cold, but you don't want to be warm/cold. So if you have a heated vest, wait until you're ascending before turning it on.

 

[tbone1004]

@BurhanMuntasser simply put yes. Cold is good, warm is bad for nitrogen absorption, and warm is good/cold is bad for offgassing.
Ideally you want to be cool/comfortable during the ongassing phase, everything leading up to the ascent, and then you want to warm up during deco. I.e. if using a heated vest, don't turn it on until you start ascending.

Part of the problem with wetsuits is that you suffer cumulative heat loss, so your body temperature is basically constantly cooling off during a dive and it is worse as the dives get longer and stack up on each other. While the suit will also decompress, your body has to still actively heat the suit up since it is at ambient temperature and will naturally cool off due to the lowering of the pressure on the air bubbles. Drysuits do the same thing with passive insulation.

 

[BoltSnap]

@BurhanMuntasser simply put yes. Cold is good, warm is bad for nitrogen absorption, and warm is good/cold is bad for offgassing.
Ideally you want to be cool/comfortable during the ongassing phase, everything leading up to the ascent, and then you want to warm up during deco. I.e. if using a heated vest, don't turn it on until you start ascending.

Part of the problem with wetsuits is that you suffer cumulative heat loss, so your body temperature is basically constantly cooling off during a dive and it is worse as the dives get longer and stack up on each other. While the suit will also decompress, your body has to still actively heat the suit up since it is at ambient temperature and will naturally cool off due to the lowering of the pressure on the air bubbles. Drysuits do the same thing with passive insulation.

And how much of an issue is this? 0.0000001%? You aren't trying to say that divers are dropping down like flies getting bent because they are wearing wetsuits and drysuits that conflict with what you are stating, are you?

 

[stuartv]

And how much of an issue is this? 0.0000001%? You aren't trying to say that divers are dropping down like flies getting bent because they are wearing wetsuits and drysuits that conflict with what you are stating.

I believe the issue is real, but probably only a significant concern for technical diving. I would GUESS that people doing recreational dives (i.e. single tank, with no deco stops) simply aren't in the water long enough nor deep enough to have any significant incidence of getting DCS as a result of a warm/cold dive.