On Wed, 28 Feb 2001 08:22:08 -0600, Mike <[log in to unmask]> wrote:

>> >It seems to me that, in part, much will depend on the intensity and
>> >profiles of the diving over the preceeding days as well as the
>> >algorithm of the computer - something that fails to consider individual
>> >physiology.
>
>Another thing to consider is what you body is telling you after
>agressive profiles. I think that many divers fail to read the signs that
>their body is giving them.

There is even a term "bio-feedback" for this sort of listening to
your own body.


>If you are feeling progressivly more
>"fatigue" after several dives over a few days then you should allow
>more time for your body to recover. This is something that you can
>feel but the algorithm of your computer can't.

Excellent point to bring out.  EXTREME fatigue (though short lasting)
is one of the unmistakable signs of "marginal bends".  So are
non-lasting shoulder aches, and others.  When your BODY is not
feeling tip-top shape, listen to what it's trying to tell ya.  :-)


Here's a lesson *I* learned about computer diving.  The ORCA algorithm
(for no-deco, no gas mix) is unquestionably the MOST RELIABLE and TIME
TESTED algorithm to date.  It had been through millions of dives over
the years by recreational as well as professional divers with no
obvious quirks.  That's why I still carry two, on long series of
repetitive dives on liveaboards.

So much for the background.  In July 1997, I decided to do my "wall
research" in Cozumel.  :-)  For 21 consecutive days, my shallowest
first dive was the one to Devil's Throat (130-ish).  The other
20 days were short bounces to max depths between 190 and 200 fsw. :-)

On EACH day, I did only two dives, and the "wait to fly" time was
usually around 6-7 hours.  So, to conserve battery, instead of letting
it run till it reach the "turn me off" point, I turned the computer
off each day and re-started on the next day.

By the 19th consecutive day, I began to feel some mild shoulder ache
and more than usual fatigue that dissipated quickly after the 2nd
dive.  When the same recurred on the 20th day, with my body sensing
a SLIGHT escalation of these symptoms, I went to the Cozumel Chamber,
together with my laptop of all dive profiles for those days, to have
myself diagnosed for DCI.

The Chamber physician gave me a short physical, sticking and running
some pins on me :-)  then put me on oxygen for about 10 minutes and
told me there wasn't anything wrong.

It was THEN that it had dawned on me that I was on the verge of
something called sub-clinical bends, and the REASON was that I had
turned off my ORCA computer when I shouldn't have.  In order words,
over the period of 20 consecutive days of diving, with deep bounces
everyday, the cumulative effect of the SLOWEST and the non-existent
(in ORCA) SLOWEST compartments would have signalled a much longer
"safe to fly" and other computer diagnostics that I did not observe.

From then on, I NEVER turn off my ORCA to save battery until it
says "turn me off".  Sure enough, even for mild two-dive a day
profiles, with 6 to 8 hrs of SAFE TO FLY wait indicated after the
2nd dive, my usually kept running till the dives of the next day
and keeps running continuously through out trip of diving everyday.

-- Bob.





>~~~~~~~~~~~
>Mike
>~~~~~~~~~~~