Re: [PSUBS-MAILIST] question for technical divers

[SJSVOB@aol.com]

I'm not a tech diver but I have read much on the subject.  Please read my words with a critical eye and seek professional guidance!

  You've posed a very open ended question.  I'd have to know more information to make my guesses to the questions you are seeking answers.   Here are some questions for you.

How long would it take you to flood the sub and get out?  Or in other words, how long in seconds would you be breathing compressed air before you started the ascent.
Your sub can go to 1000' but is your average depth different than this?
(My guess is that it would be better to carry the best gas for the average depth.)
In the event of a bailout would emergency personnel be waiting for you at the surface with oxygen?  How about a recompression tank on a rescue ship?
The bigger your bailout bottle the higher your odds of survival.  So to ask what size bottle you need when space is confined is rather strange.  How much space do you have?
Would it be possible to grab one of your existing oxygen cylinders and take that with you in addition to a bail-out bottle? This could make a huge difference if you were able to do a decompression stop and breath pure oxygen for a while.

Some answers I can give you now:
You only need oxygen cleaned equipment if your breathing gas has more than 40% oxygen.
I do not think you would want to use solely an oxygen enriched gas mixture as oxygen poisoning then becomes a concern at depth.  Divers use nitrox, or oxygen enriched air, not to dive deeper but to extend their diving time.  Their maximum diving depth is actually reduced due to the risk of oxygen poisoning.  Divers routinely swtich to nitrox or pure oxygen as a breathing gas while they are decompressing at relatively shallow depths to speed off-gassing of nitrogen.

-Stephen





There were quite a number of technical divers at the conference, and I have a 
> question I forgot to ask you guys… I’m an air diver, but my sub should go far deeper (1,000’) than I could on air. So the question is this; can I carry something better in my bailout SCUBA tank to extend the bailout depth possibilities? There are several aspects to the question:
>
> -          On the understanding I’m never going to use this for anything other than getting directly out and up, do I need training beyond what decompression diving on air would entail? I’ve been diving for over 20 years and consume less than half the air of most divers, but I know nothing at all about gas diving.
>
>  -          What gas mix?
>
>  -          Does that require an O2 proofed reg or anything else special on the HW side?
>
>  -          What size tank would be suitable for bailout? Bear in mind space is at a real premium.
>
>  -          What bailout depth would you consider realistic?