Isaac, we have found that 12 minutes on, 6 minutes off is the ideal. We only
do oxygen at 30 feet in a habitat where we have caves that accommodate this.
Otherwise we do oxygen at 20 feet or slightly less in the water with the
same schedule. If anyone wants to go back over why we do this and how we
determine bottom gas , deco gas and exposure ( or how we arrived at what we
do), I can repeat it .

>-----Original Message-----
>From: Isaac Callicrate [mailto:icallicrate@ho*.co*]
>Sent: Saturday, December 08, 2001 2:51 AM
>To: mjblackmd@ya*.co*; techdiver@aquanaut.com
>Subject: Re: Oxygen Clock
>
>
>Im not sure why everyone is harping on who this guy is or what he
>has posted
>in the past instead of answering his questions.
>Am I missing something in the charter that says you have to rate an answer
>or that previous posts disqualify you from getting one?
>Ill give it a shot even though there are probably more informed qualified
>people on this list that should be.
>I see WKPP as crossing the grey area between recreational and
>working diving
>(watch out for OSHA, ADC, and USCG). They are performing dives where more
>compartments are saturated than most other recreational profiles.
>They have
>been diving similar profiles over and over so have built up an amount of
>historical data combined with some doppler research that they have used to
>make assumptions about their profiles.
>I dont think anyone can say right or wrong yet. If their people
>arent having
>DCS manifestations or O2 toxicity issues than I would definately
>say that by
>being the guinea pig and letting the rest reap the rewards of the
>data they
>are rising above.
>Please do the math on a Navy standard TT 6A with 50/50 @ 165' and 100% @
>60'. Do it on a Navy single exposure of 100% at 25' for 240 minutes.  Why
>havent you e-mailed them? Please CC me when you do. I think it is
>publicaffairs@ne*.na*.na*.mi*
>WKPP isnt the only one that challenges theoretical formulas and
>assumptions
>with historical data. Commercial, military, hyperbaric facilities all have
>modified the standard thinking on the CNS clock.
>My personal feelings, I wouldnt recommend pushing the clock on a working
>dive when not required. For recreational dives, there is no need
>to push it
>when you are having fun. If you use a habitat or a chamber or
>maybe at rest
>during deco with surface support, the risk is minimized.
>I dont think that taking breaks off O2 is going to significantly
>effect your
>susceptibility to a CNS hit. That is speculation and if anyone has data to
>prove otherwise I would love to examine and try to push it through to some
>people.
>About cumulative pulmonary issues, I would absolutely take breaks every
>20-25 min for extended exposures. With increases as neccessary.
>The only big no-no I see is deco on 100% @ >1.6 w/o a ffm, hat, or in a
>controlled environment. I dont think WKPP is doing that. I think
>they use a
>habitat for extended oxygen. Their protocol incorperates breaks between O2
>periods.
>What data is NOAA basing their CNS clocking off of? Historical or
>Empirical?
>Do you side with someones calculator or slide rule?
>For technical diving I think everyone should be taught to do a
>personal risk
>analysis for Accelerated Deco vs O2 tox.
>Where do you draw the line? We can use good models for DCS and pretty much
>say if you do this profile you will get bent. O2 clock is more like
>speeding. Doing 25 is safer than 65 or 100 or 20,000. We dont know
>where you
>cross the line to get in a guaranteed O2 "accident". We need more data.
>All said, everyone enjoy your hit, have the ME e-mail me.
>
>>From: "Michael J. Black" <mjblackmd@ya*.co*>
>>To: Aquanaut Mail <techdiver@aquanaut.com>
>>Subject: Oxygen Clock
>>Date: Wed, 5 Dec 2001 16:26:40 -0800 (PST)
>
>
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>
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