Mailing List Archive Mailing List Archive
----- Original Message ----- From: Matthias Voss <mat.voss@t-*.de*> DB> PADI Nitrox, when taught by the book, is probably beyond at least 20% of rec divers. MV> ? Are you saying it is beyond the capacity of learning ? for how much % , 80 or 20 % ( Would it make that much difference , anyway ) I believe about 80% would eventually pass and about 20% would continue to fail, more than enough to put many dive shops under. I know people who can't handle the math for Nitrox certification so they are eternal Nitrox students and only dive Nitrox with their instructor. DB> The surface interval tables present one big challenge. On the third repetitive dive, we are already walking on thin ice by trying to represent multiple compartments with a single letter code. At least with Nitrox, the air surface interval tables (which are really nitrogen tables since oxygen isn't an issue) work for every oxygen/nitrogen combination and for the first two dives, they are adequate. Getting a table to represent helium surface intervals wouldn't be too hard, but would an OW diver be able to switch back and forth? MV> Would he care to ? I think so. I spent a week on Bonaire and as I recall the pattern was something like 130 feet or less on the morning dive, 100 feet or less in the afternoon and 80 feet in the evening. It has been a while so the numbers may be off, but you get the idea. I would imagine many outfits use a similar scheme. Using helium for the evening dive would make little sense since it shortens the no-stop times and narcosis is a minor or nonexistant issue. Why use helium when it isn't needed? DB> There would need to be different surface interval tables for each combination of helium and nitrogen. MV> Well, with proper design, such tables could be generated and made understood. Might look similar to surface intervall/ residual nitrogen tables. I think they would be pretty complex. The nitrogen and helium would be at different partial pressures for each mix (including Nitrox and air), so some allowance would have to be made for the differences. Mandating a minimum surface interval might cover this (like PADI does for Nitrox), but I don't think the other problems will be resolved any time soon. Don Burke Chesapeake, Virginia ____________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'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]