On Mon, 24 Nov 1997, Dennis JR Harding wrote:
> David,
> 
> The profile was based on Abyss 100.  Amongst some of the physiological
parameters
> set included setting 
>    'Smoker' - there was one smoker amongst us, the Course Director.
>    Age = 41-50.  The oldest were the course director & his assistant.  The
rest of were all younger.
>    Slightly overwieght - which Hennie and I were (say by 15kg).
>    We were all in good physical condition (or appreared so).  All were active
divers involved in 
>      Cave and Extended Range diving.
> 
>    Dive suite and environment, water temp was set 10 degrees celcius, and
suite type was set 
>     to 5mm wet.  Hennie & myself were indeed wearing dry suites.  I used
Argon.  I can't remeber
>     at this stage what Hennie used for inflation.
>

Look, I want to say this once, and loudly: THOSE CONSERVATISM MODIFIERS 
ARE ABSOLUTE BULLSHIT.  There is no recognized method (by decompression
experts) for adding conservatism for workload, fitness, and cold - in fact,
the US Navy did studies that show deco models completely fall apart
in well-chilled divers.  Chris Parrett knows this, but thought he'd be 
a real feature-hound if he added in all that mumbo-jumbo about
suit type, fitness level, etc.  And sure enough, the uneducated are awed
by all the shiny lights.

I always suspected as much, but didn't fully realize just how much
bullshit this is until I sat down and coded up a decompression program
(freeware, soon to be released).

If you see a program that has all those black-magic modifiers
it should tell you one thing: the programmer is full of shit.
He reached way into his butt and pulled out a conservatism
scale for factors even the experts know little about.
If you see anything but a simple, single,
conservatism value in dive software, the author is pounding
sand up your ass, and venturing into territory where 
the *real* experts won't tread.  Caveat Emptor.

BTW, I am NOT suggesting that Parret's software was responsible
for this death - in fact, I highly doubt that, it sounds like
the guy was predisposed for deco problems (PFO?)  Abyss has
so much default conservatism built in, it is useless for 
anything but a bounce (which this was).

-Will

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