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From: <kirvine@sa*.ne*>
Date: Mon, 15 Nov 1999 17:24:40 -0500
To: Scott <scottk@hc*.co*>
CC: Techdiver <techdiver@aquanaut.com>
Subject: Re: "Helium willies"
If you compare the original Navy scuba 21% oxygen heliox on heliox
tables to the air on air tables, the difference was that the helium
tables started one or more stops deeper than the air.

The reality is that the air tables should have started at the same stop
as the heliox.

Also keep in mind the source - the Navy used to "roll" the tanks in a
rack for six hours prior to using them. We use them as fast as we can
get them to the water.

Sometimes these old beliefs get passed on for quite some time before
they get corrected.


Scott wrote:
> 
> > The "willies" is bullshit - reality it what is scary, and helium gives
> > you just that - too much reality. Anyone who is doing ridiculous diving
> > or chamber experiments SHOULD be concerned - very concerned.
> > Anesthesizing them with nitrogen is not the answer.
> 
> Affirmative! Ron said the nervousness was because your body and mind *knew*
> it was not supposed to be operating under these parameters. He also said
> that HPNS was really affected by the rate of compression. That, after a
> couple days at 850, they would smooth out a bunch. On the rapid drops they
> did, HPNS was so bad that doing anything usefull after hitting the bottom
> was out of the question. "You couldnt even hold a cup of coffee."
> (important if you're a swabbie!)   =;-)
> 
> > Helium and heliox require shorter , not longer decompressions. What the
> > real story is that the "air" tables are all wrong, and should be longer
> > than trimix ( all things being equal ) and in fact air should require
> > the deeper stops that helium seems to ask for in the current "models" in
> > use. The misconcpetion is then that high helium needs more deco. The
> > more I have, the less I do.
> 
> So, if I get all this correctly, there are no accurate Air, He02 or trimix
> tables, born out by the *fact* your
> guys are still ambulatory and here to post.
> 
> Now, we all understand that you *do not* represent the typical diver.
> 
> So, with that in mind, how do *we* mortals generate safe, accurate and
> reasonable
> He02 tables?
> 
> > Ask our deco geeks what they have obvserved with me, Mee, Trout, Rose,
> > JJ, Werner etc. for confirmation of this, and this is born out by
> > doppler and blood tests, not supposition and bullshit.
> 
> Any of you deco geeks reading this?
> 
> > As for Jablonski's choice of gas for the Britannic or any other dive, it
> > is a function of the availability of a booster pump only.
> 
> <snip>
> 
> Understood. This is/was the basic reason for trimix in the first place, as I
> understand it.
> 02, He, HP air to top.
> 
> <snip>
> 
> > Scott, it is real simple: 1) you need to be as clear as possible when
> > diving - heliox gets that done, 2) you need a fast gas that does no
> > damage of its own ( as nitrogen does ) and is actually inert - that is
> > helium, and 3) you need to have no preconditions ) inluding excess
> > adipose tissue ), you need good vacularization and perfusion ( i.e. good
> > genetics), you need to be in good cardiovascular condition, and you need
> > to be free of any injury or damage prior to diving, and you need to have
> > no pulmonary reactions to these stresses, no blockage or swelling of any
> > gas spaces, and you need to be armed with real information, not drooling
> > bullshit like this "helium willes" nonsense.
> 
> Can we use the  Buhlmann tables/algorithm for He02 or should we be looking
> elsewhere?
> 
> The Navy tables also call out longer deco on He02. *That* doesn't make
> sense.
> 
> Scott
> 
> --
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