Re: [PSUBS-MAILIST] PSUB Fatalities...

["Sean T. Stevenson" <ststev@uniserve.com>]

Phil, I realized that my reply to Carsten was inappropriate in its
apparent hostility, and subsequently posted an apology to the list. 
The tone of my reply definitely did not come across as it was intended.
 I do not wish to offend anyone, but the only way to be 100% sure of
that is not to contribute.  I really am a good guy... honest.  My
mistake, I acknowledge that.  Let's move on...

Perhaps you could elaborate on the criteria you use in selecting an
escape gas.  If we are talking about a straight shoot for the surface,
no lolligagging about type of profile, would more exotic gases such as
neon or argon (larger molecules, presumably slower uptake) have any
application here?  The Newtsuit escape stuff is pretty interesting. 
Were the tables that you and Mike Gernhardt proprietary or ???  What
exactly is the escape procedure?

-Sean


On Wed, 8 Mar 2000 21:54:13 -0500, Phil Nuytten wrote:

>Dear Sean:
>        Noted your response to Carsten: > Sorry to have to call you on
>this, Carsten, but it's garbage . . .etc.<  Wow! don't you think that's a
>little . .uh . .harsh?    'Garbage' ?? You'd think that there would a way
>of making your personal opinion known without  the risk of offending
>some-one who is, after all, just giving you and the rest of us the benefit
>of his opinion. Just dismissing it as 'garbage is like me saying that your
>opinion that  >> Helium is a much friendlier gas than nitrogen, from a
>decompression perspective - it ongasses  quickly but also offgasses quickly
>. . .etc.<< is 'Stupid' or ' Misses the whole decompression dynamic point .
>. .etc.' Not real polite!
>        You might want to consider that, if helium is given off at the same
>rate that it is taken up, then Heo2 tables would be very simple; since the
>required decompression could never exceed the bottom time. Alas, the
>gas-driving pressure differentials are entirely different on descent and
>ascent - but then, hell, you know all that . . . just like the rate of
>saturation at a given pressure differential being a significant function of
>the oil-water solubility ratio of the gas, rather than simply the molecular
>mass - but, hey, Overton and Mayer showed that before the turn of the last
>century . . so it's hard to overlook!
>        Heo2 would be the last mix I personally would choose as a submarine
> escape gas. I'd opt for good ol' 02N2 every time . .with a nitrogen
>equivalent air depth of about ten ats relative (330 feet) and a relative
>oxygen depth of about 90 feet - balance composed of  dat debbil helium.(
>You mentioned Albert Buhlman . .you probably remember his description of
>his colleague Hannes Keller diving to 360 feet on an 02N2 mix with with an
>oxygen concentration so low it gave a nitrogen equivalent air depth well in
>excess of 400 feet - all with no sysmptoms of narcosis.) 
>        I personally would have no hesitation about free escape up to about
>one thousand feet. At depths up to about 750 feet, with low He levels,
>there is a high chance of no clinical manifestations of bends - at least 
>according to bubble growth dynamicist
>Mike Gernhardt who ran the math for us when we were doing extensive studies
>on free escape from the Newtsuit at depths up to one thousand feet -  (
>Mike has been in the NASA astronaut program for years and has completed two
>space shuttle flights - not bad for a former saturation-diving
>physiologist!)
>        So, I guess Carsten may have been pretty conservative in his
>estimates of escape depths and times, after all !
>
>        It's all pretty interesting stuff - I spent a lot of time on table
>formulation and testing  before deciding that one atmosphere was the way to
>go.     
>        Anyhow, my point was that it's probably not politic to dump cold
>urine on some-one else's opinion - in my opinion, of course!
>Phil Nuytten