Originally posted by Green_Manelishi
deep air.
aside from the incredible narcosis effect (and that can be mitigated to lesser/greater degrees with the use of helium)
you are pretty much at the *safe* limit for an air dive when
you are at 180 fws (based on PO2)
Nothing says you Have to go to 180.. The class in not necessarily about going to deeper depths but is a useful continuation of deco training.. You learn more contigency planning and diving physiology. A person can do all the dives in the 130+ range and still meet standards.
In SOME areas where HE is not available and wounldn't be the next class to take using this class to deeper depths is an option(I'd still like to keep it to depths were narcosis is manageable).
Some training and experience is better than having the person just decide to do it on his own. Many of those against deep air don't realize how easy we have it getting He compared to many dive destinations around the world. If people who advocate deep air is the devil, always use helium... why not use neon.. its in the same class for us in the states as He is for many around the world.. Its very difficult to get and Very expensive.. but potentially a better gas for short deep dives.
Going deeper on air has to be an individual risk assessment. I don't profess it to being safe, under normal situations I limit myself to 150ish on AIr.. I'll do He deeper than this, but there are times I will go deepr and assume the risk involved. The conditins must be optimal and the proper support available. I recently dove TRUK and anyone who has been there knows what its like to try and get He there.. I understood the risks involved and did the dives I wanted to do... I had to worry more about narcosis than otox since I was on a ccr and beyond 170 my PN2 is greather than that of an OC diver..
If I chose to limit to 150, the enjoyable dives on the SanFranciso Maru, Shotan Maru, and Aioku(sp) Maru would have been out of the question, with the Shotan being the shallowest at just under 180. Granted I would never do these depths in cold, limited viz water, but in 84 degree water with better than 100feet viz, its not that difficult of a dive..