Quote: (Originally Posted by Andy Del)
This just goes to show how different people are as far as tolerances go. I did just one dive using trimix to inflate my suit (during my TX course
). It was to 78m and the water was around 17C. Last 30 minutes of deco I was shivering uncontrollably and felt extremely cold (not surprising really). Using something other than helium (travel gas, or these days my nitrox bailout) doesn't see me feeling cold in this manner anymore.
My question is, if using N2 (or a similar gas, such as O2[?]) in the suit and helium as a breathing gas, or vice versa is a bad idea, then should one and how should one, take this into consideration as the gas we breathe changes as we ascend?
You are right in that variance is a big issue: I spoke purely from personal experience and forgot that I am probably not average in this particular instance - I dive without a hood when the water is more than 52F, and feel quite comfortable most others on the boat use a hood and still feel cold. For me, I did not see any difference with helium, and do not shiver or feel cold with it, but accept your point: other people may need a different solution. I do not think that solution is a different gas in the suit through.
If you feel cold with He in the suit, you could use a heated jacket like the Typhoon Icebreaker or the EXO2 jacket to keep warm. Doing that is better than mixing gas in the suit just for warmth.
The underlying issue behind my decision is the evidence of bends when using a different mix in the suit to that one is breathing: some interesting papers on this, for anyone wanting to look.
Cheers
Alex