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Nelson, we originally went to Hamilton Research for custom trimix tables.
Dr. Bill Hamilton is a physiologist and worked in oil company and other
environments where mixed gas tables were first employed. What he developed
for WKPP dives were initially very long schedules, which actually helped our
gear thinking since Bill Gavin wanted to speed up the dives as much as
possible to avoid the long decompressions first believed to be necessary. He
and I could add and survey 1000 feet of line every six minutes.
When Parker died I became the one who interacted with Dr. Bill and we used
me as the test subject for shortening the tables and changing the shape, the
depth of the stops, and the gasses used. I boosted the helium , again quite
by accident as I was also the survey guy, so I needed to be mathematically
clearer. Suddenly I could do a whole lot less deco - the fist thing that was
counter to conventional wisdom on helium. I could find no deco that worked
reliably for weak mixes or air. Gavin and I tweaked the tables repeatedly by
using software containing Bulhmann, but giving it false values for helium
and oxygen percentages, like telling it the helium was lower and the oxygen
higher than it was to get the right shape we believed was better - it was.
We changed from using 40% and O2 to inserting a 50% bottle to make the
intermediate stops more effective, and then started using the 190 bottle for
deep stops. This JJ and I converted to 19X35 after several iterations. Then
JJ started adding helium to the 120 bottle. I axed the intermediate stops
way back in concert with Hamilton's recommendations and we just smoothed it
out until we found the ideals using Doppler and me and JJ as a test case .
JJ and I would hang around by the water in our dry suits in case we had to
get back in, and get bubble checked until clear.
The deco development down to reasonable schedules and techniques that work
across the spectrum is one of our biggest contributions to tech diving, and
trust me we got nothing but badmouthed and were fought all the way on that
one. Notice now the Dr. Weinke and NAUI have now corroborated our results
using the chamber at Los Alamos and sophisticated tracking techniques.
Notice they also allow teaching of DIR.
-----Original Message-----
From: NPerry255@ao*.co* [mailto:NPerry255@ao*.co*]
Sent: Wednesday, November 01, 2000 9:27 PM
To: trey@ne*.co*; techdiver@aquanaut.com
Subject: Re: DIR clarification
Thanks for the historical perspective (always wondered about
"Hogarth!");
it makes the posts more informative... Probably many List divers (inc. me)
don't personally aspire to the extreme pioneer exploration that WKPP does:
but your success and the knowledge gained -- and shared -- benefits the
whole
tech diving community. Particularly important are the radical changes in
decompression theory AND application, which you & JJ have put to the test.
(On a small level, it was from the List that I learned to use 50% O2 (not
36%), pick a lower END (90') and incorporate proper deep stops (GUE Deco
Planner or RGBM). Safe diving,
Nelson
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