> I can't say I know alot about the Cis Lunar and how the processing works
> but Ken are you implying that the Cis runs pure Buhlman? I thought it ran
> Proprietry code

It does not use Buhlmann; it uses DCAP. I am unaware of any deco algorithm
that adjusts shallow stops based on violation of deep stops.  If there was
such an algorithm, I sure as hell wouldn't use it.

Let me try to explain something about deco.  I'll put it in terms that the
DIR-heads can understand.  When it comes to sub-saturation, helium-based,
longish deco diving, all decompression algortithms are (to a greater or
lesser extent) "convoluted strokery".  Purely compartment-based models are
high in the "strokery" category, because they probably entirely miss the
most important factors for this regime of diving. Bubble-based models and
other integrated models, on the other hand, are pretty far into the
"convoluted" catgeory: even though they may come closer to the mark in
terms of what factors to take into account, there is very little real
world and/or experimental data to verify the mathematical premises of
these models, and therefore they represent a level of excessive complexity
without empirical backing.  Perhaps the worst form of "convoluted
strokery" of all within the world of deco models is the highly contorted
"modified" compartment-based model, because this suffers both from
high covolution and high strokery at the same time. Any deco model that
would atttempt to "reconfigure his up coming decompression stops" in
response to blown deep stops would represent this worst kind of deco
model.


> unique to the respective mark (ie 5, 6 whatever) and thats after you get

Huh?  Unique to what?

> Ken Sallot wrote:
> 
> > Standard decompression tables (pure Buhlmann) cut the first deco stop
> > really shallow right off the bat for short excursions to 300' (90m).
> > A couple of years ago I did a dive with a guy, max depth 310',
> > ACTUAL bottom time 20 minutes at 300', the first deco stop the tables
> > called for were at 120'. Knowing better, I stopped at 210', and did 1
> > minute stops all the way up, however my dive partner refusing to
> > believe that was deco, went straight to 120'. My stops were all
> > shorter than his, and I caught up with him at 70'. At 60' I passed
> > him, and eventually I surfaced 15-30 minutes before him. With the
> > support personnel I wasn't worried about leaving my buddy to finish
> > out his deco by himself..
> >
> > At any rate, even though he followed his straight tables by the
> > numbers, he had to do 3 chamber rides before he was quite "right",
> > where I had no problems.

One more empirical experience in support of the value of deep stops.
Somebody ought to start tallying these kinds of experiences.  Without
controlled conditions it would take a lot of them to start revealing a
statistical trend; but I'm pretty confident that trend really does exist.

> > Maybe Poole did the deep stops that Vanders didn't? They did state
> > they felt Vandersleet missed the deeper stops, even though the
> > CIS (and definatly Buhlmann tables) don't take into account for them.

One thing I like about DCAP is that for a given profile, the initial stop
is usually much deeper than straight Buhlmann.  This deeper first DCAP
stop is what I use to calibrate my first deep "safety" stop, so my deep
stops tend to be somewhat deeper than deep stops derrived using the same
method but based on a Buhlmann table.

> > Also, Poole might have equally played russian roulette and gotten
> > away with it.

Actually, I think this is the most important and relevant point of all.
What many people fail to realize is that *ANY* sub-saturation helium dive
is experimental, and all divers who conduct such dives should consider
themselves Guinea Pigs, and trimix diving is, and will continue to be, a
form of russian roulette for a long time to come. Period. The best we can
do is try to decrease the odds of having the loaded chamber come up.
There aren't many such things that we have confidence in, but good
hydration and deeper initial stops seem to be in the running.

Also, the apparently low incidence of bends among trimix divers doesn't
amount to much, simply because the denominator is so small.  There are no
guarantees of any kind for any sort of diving, but the deeper ou go, and
the more you dick with the gas mixtures, the more of a gamble you are
taking.

> > Oh well, it'll be interesting to see what happens when they attempt
> > real bottom times. I do hope the guy's OK, but hopefully he won't do
> > something stupid and try to dive deep right away.

From what I've been told, he is fine, and he will not be diving again
anytime soon.

Aloha,
Rich

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