i know...another gear question.

[Anti-Hero]

It is not anecdotal. If you start a dive warm and end the dive warm, normal dive tables apply. If you start a dive cold and end the dive cold, normal dive tables apply. If you start a dive warm and end the dive cold, normal dive tables do not apply. There are no special cold-water tables. Normal tables assume a rate of off-gassing which will not happen if you are cold owing to reduced perfusion (blood flow into and out of capillaries and peripheral tissues). If you were cold to begin with, you will have absorbed less N2 into your peripheral tissues (during a dive) owing to decreased perfusion. If you were warm or "normal" to begin with, you will have absorbed N2 at a normal rate as the dive progressed. However, if you subsequently became cold you will not be able to lose N2 from your peripheral tissues at the rate that tables rely upon. DCS is therefore more likely to occur. See the excellent article at http://rubicon-foundation.org/Download/Pollock/Cold_Stress_Complicates_Deco_dirQuest2003_4_1 14-16.pdf for more information.

PS - avoid the hot tub after a dive if there is a chance that you were near your NDL limit.

Safe diving!

The occurrence of DCS is a complicated matter, owing to more variables than simply temperature. Your link isn't working for me, but I'm guessing the sample size of data is inconclusive, thus again, making the data anecdotal.

As an example, I start almost all of my dives warm and end up quite a bit colder, as do most cold water divers, and I personally don't know anyone who's been bent in what cumulatively amounts to thousands of dives.

 

[dhuskins]

First things, first. Before investing in an expensive piece of gear, make sure you love diving. Make sure you love cold water diving. Make sure you have the ability to schedule cold water dives.

Then make sure you know what it is you want. There are many brands out there and each have something different to offer.

Finally, weigh the cost and convenience to the change in the quantity of dives you will get from diving more often and more comfortably. If you break even or feel you would be ahead, then go ahead and get the dry suit.

I love mine and just came back from a Monastery, CA dive that was about 48 degrees. Two of my dive buddies came up complaining of the cold (wet suit divers). The rest of us looked knowingly as each other (dry suit divers) and in mock dumbfoundedness wondered what they could possibly be complaining about.

 

[Crush]

The occurrence of DCS is a complicated matter, owing to more variables than simply temperature.

Of course it is. My post referred to only one factor which contributes to DCS.

...but I'm guessing the sample size of data is inconclusive, thus again, making the data anecdotal.

I wish that I had your ability to be able to analyze scientific publications without reading them - it would save me much time in my professional life. One study cited in the broken link involved an analysis of 177 dives over a six year period

Try the following - I hope it works.

"http://rubicon-foundation.org/DownloadPollockCold_Stress_Complicates_Deco_dirQuest2003_4_1 14-16.pdf"

I personally don't know anyone who's been bent in what cumulatively amounts to thousands of dives.

We seem to have different understandings of the mechanisms of nitrogen removal from tissues.

 

[Anti-Hero]

"I wish that I had your ability to be able to analyze scientific publications without reading them - it would save me much time in my professional life. One study cited in the broken link involved an analysis of 177 dives over a six year period"

I must be psychic. 177 dives over a six year period is statistically insignificant, relative to the amount of divers and dives completed each DAY, let alone in a YEAR, and so far removed from 6 years it's moot.

"We seem to have different understandings of the mechanisms of nitrogen removal from tissues."

I'm sure with your whopping ~100 dives and vast knowledge you're not developing your own decompression algorithms. You might impress the newbs in the beginner forum, but you're not impressing me with your knowledge or sarcasm.

 

[Crush]

I must be psychic. 177 dives over a six year period is statistically insignificant, relative to the amount of divers and dives completed each DAY, let alone in a YEAR, and so far removed from 6 years it's moot.

Read the article. They analyzed their results statistically.

What is your formal training in statistics? I am curious.

I am also curious what your training is in dive physiology. I am not a physician, but I have completed several diving certifications, during the preparation for which I have learned (among other things) about mechanisms of nitrogen elimination. Have you been taught that cold water has no effect on DCS onset, or perhaps that it is beneficial?

I'm sure with your whopping ~100 dives and vast knowledge you're not developing your own decompression algorithms. You might impress the newbs in the beginner forum, but you're not impressing me with your knowledge or sarcasm.

Ah, the ad hominem fallacy. You are welcome to attack my limited diving record if that gets you off, but you can't be intellectually honest if you substitute your attack of my person for any meaningful defence of your position.

I have offered you four peer-reviewed articles (one link to an article which cites three other articles) and a physiological model for how cold water complicates deco. I can also suggest MDs on SB who agree with this premise. You claim the studies to be flawed without having read them and you have attacked my person. You wouldn't by chance also believe that global climate change is a hoax, would you? That would explain a lot...

 

[Anti-Hero]

LOL - you sure are full of yourself. I'm sure the NAUI "Master Diver" card is extensive in it's training requirements, however I'm not interested in circle jerking with you anymore. With that said I'll keep taking hour long boat rides in the sun in 300g undergarments and a drysuit (read: starting *very* warm) then jumping into 48 deg. water for a 90 min. dive (read: ending cold) just like thousands (read: not 177) of other divers do each year here in MoCal. I'm sure your statistics are more accurate than real world experience.

 

[Anti-Hero]

OH SNAP! This is the very first sentence in the NAUI Master Diver website:

"Gain the in-depth knowledge that will establish you as a recognized authority in your diving club or group." - I was wrong about you, you ARE an expert. I will humbly submit from this point on.

 

[Crush]

Anti-Hero,

As a point of clarification, I never stated that DCS would be caused by starting a dive hot and ending it cold, just that the likelihood of this happening increases.

I feel bad about hijacking jashaw's thread, so this will be my final post under his OP. If you have any further insights, please PM me, or start a thread on the hoax of cold-complicated-deco.

Your posts have been scintillating and amusing - thanks!

You never did mention where you learned about dive physiology or about statistics....

 

[ScubaSteve]

The good thing is that in reality, this whole DCS argument has nothing to do with whether the OP should purchase a drysuit or not. It really has been nothing more than for the enjoyment of the readers. I think we are all glad it is over.

 

[Doc Harry]

I will be doing about 95% of my diving in the great lakes and other lakes of michigan. Is it ABSOLUTELY necessary to have a dry suit?

Only if you want to be warm and enjoy yourself and dive a lot.