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Thanks for posting publicly. I have heard some good private posts that should have made it on this list. I have been in love with the VPM since I read on it. I dont think I have seen anything in the last five years about it so if you have any good references I would be very thankful. >From: wgrogan@dc*.ne* >Reply-To: wgrogan@dc*.ne* >To: icallicrate@ho*.co*, techdiver@aquanaut.com >Subject: RE: Dr Black/ChamberHaters >Date: Wed, 12 Dec 2001 09:56:08 est > >Just to add a couple of things. >The Navy tables are not useful for tech diving. The first thing the Navy >manual >says is that mixed gas diving should not be done unless there is a chamber >on >board the ship. In fact, the schedules assume that you will deco to 40 >feet, >then get lifted up to the ship, stripped of your gear and put in a chamber >and >recompressed within 5 minutes. This is important for military dive >operations >and is a hold over from caisson decompression where you had to move shifts >of >workers in and out of pressure every few hours. It was much more efficient >to pull an elevator load up to the surface, rush them into a surface >chamber >as a group and decompress them that way. (We're talking late 18th early >19th >century technology here). What is pretty clear from both Navy tables and >straight >Buhlmann calculations is that you are overpressuring the tissues, >essentially >causing sub clinical bends if you will, then "treating" with longer stays >at >shallower depths with higher O2 percentages. The first attempt to address >this >was Pyle's "deep stop" method. He is the first to tell you that this was >just >a rough guess, not based on any kind of science. Scientific work has been >done >by Baker and others, and the results are the so called Gradient Factors >which >modify Buhlmann calculations to address the overpressure problem when >ascending >from depth. There is also a fairly radical re-think called Variable >Perfusion >Modelling which is the first complete change in deco theory in half a >century. > >Johnny is right about TDI. I just read their trimix manual last week and >in >it they basically say, get a good deco program, forget tables. >The downside to using a computer program is not understanding what the >theory >is behind the program. You need to understand what the computer is doing, >and >if and how you need to modify it for your fitness, experience, dive >conditions, >etc. What the WKPP guys do is based on the fact that they self select >people >that are capable of doing extreme dives and deco. Thats not to say that >with >enough work and self discipline you can't do the same, but you can't just >wander >into the water after sitting behind a desk all week. > >Wendell > > >Hi Isaac > > > >3 years back I used to do dives that required 1-1� hr on 80%. > >On a couple of ocations I stayed 2� hrs on 80% just to see when any > >pulmonary symptoms would begin. No gas breaks done. In these exposures >there > > >was really no significant symptoms. > > > >When I do pure O2 now, I get the symptoms after 30-40min. There I'm doing >15 > > >/ 3 gasbreaks (but using the 50% decogas to "break" on) > > > >From my chamber experience and talking to comercial divers, the >inhalation > > >resistance on the O2 reg or mask, has a major influence on how your lungs > > >are going to feel afterwards. > > > >BTW, no agency is using Navy tabels anymore. I think even TDI stopped 2 >or >3 > >years ago. > > > >Regards > > > >Johnny Christensen > > > > > >>From: "Isaac Callicrate" <icallicrate@ho*.co*> > >>To: trey@ne*.co*, techdiver@aquanaut.com > >>Subject: RE: Dr Black/ChamberHaters > >>Date: Tue, 11 Dec 2001 12:48:16 -0500 > > > >-snip- > > > >>>Im interested to hear if any of the IANTD's on the list have done a > >>long > >>enough exposure to see pulmonary issues on 80/20? I hope Im not the only > > >>one > >>getting something out of this. (Everyone take a turn squeezing more out >of > > >>Trey while he is feeling generous) > >>Thanks > > > > > >_________________________________________________________________ > >Chat with friends online, try MSN Messenger: http://messenger.msn.com > > > >-- > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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