I agree.  The reason I referenced Buhlman specifically.

Art.


	-----Original Message-----
	From:	kirvine@sa*.ne* [SMTP:kirvine@sa*.ne*]
	Sent:	Wednesday, January 12, 2000 7:15 PM
	To:	Paltz, Art
	Cc:	'Oystein Mehus'; Manos Manoli; Tech Diver
	Subject:	Re: I think I don't understand

	That is if you believe that in the first place - the nitrogen causes
	damage that needs hyperbaric oxygen treatment.

	Paltz, Art wrote:
	> 
	> I don't think it's that cut and dry.  I think it depends on the
amount of
	> nitrogen in the bottom mix.  According to Buhlman (since it was
referenced),
	> if you've got a lot of nitrogen in the bottom mix then the O2 is
going to
	> get your our faster (greater N2 difference in the bottom mix).
Less
	> nitrogen in the bottom mix and the 50/50 is going to get you out
faster (the
	> He difference is 100% and it comes out faster then N2).  According
to
	> straight Buhlman (using Decom with N2/He M's set to 0%) I get the
following.
	> 
	> Same simple dive 130 feet for 45 minutes.
	> 
	> Using air you'll get out of the water in the following times.
	> Deep stops, O2 deco - 87 minutes
	> Deep Stops, 50/50 deco - 90 minutes
	> No deep stops, O2 deco - 85 minutes
	> No deep stops, 50/50 deco - 89 minutes.
	> 
	> Using air O2 wins both times by 3-4 minutes.
	> 
	> Say you are using a helium rich mixture, say 50% He, 21% O2 (want
to keep
	> the O2 the same when comparing.  What you would be doing with this
mix in
	> your tanks I don't know.
	> 
	> 130 ft, 45 minutes, 50% He, 21% O2.
	> Deep stops, O2 deco - 130 minutes
	> Deep stops, 50/50 deco - 117 minutes
	> No deep stops, O2 deco - 128 minutes
	> No deep stops, 50/50 deco - 114 minutes
	> 
	> 50/50 wins both times by 13-14 minutes.
	> 
	> With a lower Nitrogen bottom mix you're better off with 50/50 then
the O2.
	> I think it naturally comes back to picking the right gases for the
dive.
	> Naturally this is Buhlman's interpretation.
	> 
	> Hope this helps,
	> Art.
	> 
	>         -----Original Message-----
	>         From:   Oystein Mehus [SMTP:oymehus@on*.no*]
	>         Sent:   Wednesday, January 12, 2000 8:50 AM
	>         To:     Manos Manoli
	>         Cc:     Tech Diver
	>         Subject:        Re: I think I don't understand
	> 
	>         Manos Manoli wrote:
	>         >
	>         > Jeff i made many many tests with diferent Ean mixtures
belive me
	>         > 100% oxygen on 6 meters does a hell of a lot diference
than 50% on
	> all stops.
	>         >
	> 
	>         This subject interests me. Do you have any references to
	>         why this might be so? And why does not deco-programs
	>         reflect this knowledge? According to the algorithms (at
	>         least Buhlman) you'll get out sooner if you use 50% from
	>         21m than if you go straight to O2 on 6m.
	> 
	>         Oystein
	>         --
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