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For what it's worth, PADI teaches MOD is based on 1.4 and "contingency depth" is based on 1.6. Don Burke Chesapeake, Virginia ----- Original Message ----- From: Schultz, Steven <Steven.Schultz@sp*.gc*.ca*> To: 'Jim Cobb' <cobber@ci*.co*>; <klind@al*.ne*>; dmdalton <dmdalton@qu*.ne*> Cc: <dwiden@ho*.co*>; <donburke56@ne*.ne*>; 'Paul Braunbehrens' <Bakalite@ba*.co*>; <techdiver@aquanaut.com> Sent: 12 October, 2000 10:31 Subject: RE: rec trimix > Jim, > > I don't think that the problem is with recreational nitrox. I think that > the problem is the way that it is taught by the agencies. I proudly hide my > tdi nitrox shingle and hope no one ever asks to see it. > > When I took the course, they said: > -always use a bottom p02 of 1.6 except on unusually cold or strenuous dives > (then use 1.4) > -in this area all dives are cold with current and you are used to it, so > there is no problem always diving p02 of 1.6 > > This is too stupid. I didn't realize that at the time (I was 17 yrs old). > That was only a couple problems with the course. They also encouraged > carrying a bottle of ean39 beyond its MOD for use as a bailout gas. Where > have we heard this crap before??? > > Nitrox shouldn't be used to avoid a few minutes of deco, but can be used to > increase safety. A lot of people diving at altitude dive ean as air to > increase safety on recreational dives. > > The problem isn't with an 80 full of nitrox... The problem is how the > industry teaches its use. > > ss > > -----Original Message----- > From: Jim Cobb [mailto:cobber@ci*.co*] > Sent: October 10, 2000 10:13 PM > To: klind@al*.ne*; dmdalton > Cc: dwiden@ho*.co*; donburke56@ne*.ne*; 'Paul Braunbehrens'; > techdiver@aquanaut.com > Subject: Re: rec trimix > > > Kent- > > I guess I was a little obscure. What I am saying is the nitrox presumption > that you can avoid deco for certain profiles by cranking up your PP02 to 1.5 > or even 1.6. > > So I would not agree with the diver who does your hypothetical dive who, > instead of using air and getting out of the water at 20 mins, mixes a 40 > nitrox to stay in for 40 mins. Personally I would prefer do 5 mins of deco > on 02. This limits your overall exposure to to the high PP02's from 40 mins > at 1.44 to 5 mins at 1.6 while at rest. In tech diving reserving your high > PP02 for deco gives you the opportunity to do air breaks and give your lungs > a rest, something you can't do at the bottom. > > Jim > ------------------------------------------------------------------- > Learn About Trimix at http://www.cisatlantic.com/trimix/ > > > From: "Kent Lind" <klind@al*.ne*> > > Reply-To: <klind@al*.ne*> > > Date: Tue, 10 Oct 2000 16:37:53 -0800 > > To: <cobber@ci*.co*>, "dmdalton" <dmdalton@qu*.ne*> > > Cc: <dwiden@ho*.co*>, <donburke56@ne*.ne*>, "'Paul Braunbehrens'" > > <Bakalite@ba*.co*>, <techdiver@aquanaut.com> > > Subject: RE: rec trimix > > > > Jim: > > > > Maybe I'm missing the point of your post. But I do what you describe all > > the time. Not the working PP02 over 1.2 but using nitrox to reduce or > > eliminate deco time. > > > > Here's a hypothetical. What gas would you use for say a 1 hour cave dive > at > > 85' max depth? That's a pretty typical profile. Are you going to use > air, > > trimix, or something simple like nitrox 32 which you can get pumped out of > > banks at the local shop? > > > > > > -----Original Message----- > > From: Jim Cobb [mailto:cobber@ci*.co*] > > Sent: Monday, October 09, 2000 10:55 AM > > To: dmdalton > > Cc: dwiden@ho*.co*; donburke56@ne*.ne*; 'Paul Braunbehrens'; > > techdiver@aquanaut.com > > Subject: Re: rec trimix > > > > > > I know this is going to piss off a lot of rec divers but I believe that > > increasing your bottom PP02's for the purpose of avoiding a deco > obligation > > is a really stupid idea. It is typical of our sport that this principle is > > embraced by almost everybody. Even to the point of calling potentially > > deadly hyperoxic mixes "safeair". > > > > I think there should be an industry-wide ban of bottom or working PP02's > of > > anything over 1.2. And if you need to spend more time down there then you > > need to do it right with doubles and a deco plan. The idea of "standard" > > trimixes with 02 of 32 or 36 or greater is inverse to common sense. > > > > Jim > > > > On Monday, October 9, 2000, at 01:20 AM, dmdalton wrote: > > > > David, Don & whomever else, > > > > Why does this need to be a gas that "tracks" air? Anyone who would be > > interested in the minimal extra training necessary for a recreationally > > oriented Trimix would either already be Nitrox trained or certainly > capable > > of it. As was already pointed out a Tri-Ox course could easily make Nitrox > a > > thing of the past. If we are talking about "no stop dives" then wouldn't > it > > make sense to boost the O2 level to get some increased bottom time? A > 21X24 > > @ 130 ft for 5 minutes calls for 1 min at 30, 20 & 10 (Deco Planner GF - > lo > > 25/hi 90). While a 28 X 35 gives you 10 min @ 130 and only adds 1 min at > 40 > > ft to the above. Nitrox has it's limits and so would Tri-Ox. I would > venture > > to say that an individual breathing Tri-Ox of 28 X 35 would be far less > > likely to ignore the 130 ft limit than someone breathing EAN 28. > > > > As for the Rec Agencies, I think they will be the ones to embrace this mix > > which would be one more specialty that they could get into their > curriculum. > > They certainly have all embraced devil gas, I'm sorry, Nitrox. Yeah, I > know > > it took a while but when Tri-Ox hit's for real they will all jump on it > like > > a chicken on a June bug. The gentleman I took Nitrox from ( a former NOAA > > Nitrox Diver of 14 years) was talking about standardized Tri-Ox 32 & > Tri-Ox > > 36, 3 years ago when I took the course. > > > > I believe the bigger challenge is the few shops that pump Trimix. In the > DC > > area I know of only one shop that pumps it and I understand that they are > > getting in the neighborhood of $80 for a single tank of Trimix. > Outlandish, > > but then I understand that in NY you can get hit up $20 for a single of > > Nitrox. > > > > Dave Dalton > > > > > > ----- Original Message ----- > > From: David B. Widen <dwiden@ho*.co*> > > To: <donburke56@ne*.ne*>; 'Paul Braunbehrens' <Bakalite@ba*.co*>; > > <techdiver@aquanaut.com> > > Sent: Sunday, October 08, 2000 2:53 PM > > Subject: RE: rec trimix > > > > > >> Don > >> > >> Good thought. It will be hell to get the rec agency to support. > >> I ran some of the numbers through Deco Planner and some other > > calculations. > >> > >> To more closely track air and without penalties a 21x24 works with END of > > 80 > >> IAW DecoPlanner and END of 90 if you calc with N2 & O2 as narcotic gases. > >> Without building the whole tables w/SIT and repet groups. There are > > several > >> general mixes that would work well. The Normoxic value would serve the > >> uninformed or hard headed person who exceeds 130. It would also support > > and > >> assist in the transistion of new divers to this type of dive gas and > idea. > >> > >> Type Cost: 21x24 $.215/cuft 21x30 $.252/cuft > >> AL80 21x24 ~$17 21x30 ~$20 > >> ST95 21x24 ~$21 21x30 ~$24 > >> > >> Cost increase 3 to 5 times without over fills. > >> > >> David > >> > >>> -----Original Message----- > >>> From: Don Burke [mailto:donburke56@ya*.co*] > >>> Sent: Sunday, October 08, 2000 7:56 AM > >>> To: Paul Braunbehrens; techdiver@aquanaut.com > >>> Subject: Re:rec trimix > >>> > >>> > >>> Comments scattered within > >>> > >>> --- Paul Braunbehrens <Bakalite@ba*.co*> wrote: > >>>> I think that this is where trimix computers come in. > >>>> Even if it's a > >>>> good "drop in" gas, I'd still like to track what I'm > >>>> really using. > >>> > >>> Certainly. It isn't rocket science in any case. I > >>> haven't worked out _every_ possibility so the He > >>> content may have to be backed off a couple of points > >>> to stay inside the air tables. > >>> > >>> A set of rec-tri tables wouldn't seem to be too hard > >>> to make up for repetitive diving, although PADI would > >>> probably have to actually come up with a new set of > >>> surface interval numbers to allow for He instead of > >>> the Xerox solution used for the surface intervals on > >>> the PADI EAN tables. > >>> > >>> > >>>> Also, because of O2 Tox there would have to be some > >>>> kind of an > >>>> "orientation class" at the least. If you go down to > >>>> 160 on air and > >>>> come back up right away you're stupid, but you won't > >>>> tox on O2. A > >>>> "drop in" gas would need some serious warning if it > >>>> has a higher O2 > >>>> content. > >>> > >>> Yeah, the orientation would be: > >>> > >>> "Remember when I told you to stay shallower than 130? > >>> Well this time I mean it." > >>> > >>> You didn't mention the CNS clock, but since we are on > >>> the subject of O2, I haven't figured out a way to run > >>> out the clock with 28% O2 without going well into deco > >>> stop diving or going below 130. I doubt there is one. > >>> > >>>> Don Burke wrote: > >>>> ~ > >>>>> As variation on the same theme, how about 28/35 as > >>>> a "drop-in" replacement for air? > >>>>> > >>>>> It is good to 130 feet under any conditions a rec > >>>> diver will see. > >>>>> > >>>>> The no stop times are longer than for air. > >>>>> > >>>>> The END at 130 feet is about 80 feet. > >>>>> > >>>>> The only downside is cost. > >>>>> > >>>>> Don Burke > >>>>> Chesapeake, Virginia > >>>>> > >> > >> -- > >> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > >> > > > > -- > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > > > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > ____________NetZero Free Internet Access and Email_________ Download Now http://www.netzero.net/download/index.html Request a CDROM 1-800-333-3633 ___________________________________________________________ -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. 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