Mailing List Archive Mailing List Archive
<Wrolf.Courtney@do*.co*> wrote: > >How deep is too deep for air? > >Your votes for the following extremist positions please. [snip] That's the curse of a democratic society; too many questions that should be answered by scientific enquiry get thrown open to the opinion polls instead. A year or so ago there was a thread that started with G3 saying he had had enough of Techdiver and was dropping out for awhile; somebody posted a followup and said "oooh goodie; it's safe to talk about deep air now". I promptly challenged that person and the rest of the readership with the question of how deep are people thinking when they say "deep air", thinking that to one group they're talking about air up to a reasonable limit when they say that, and to another group the words "deep air" mean air beyond any sane limit, and of course the two groups are going to argue with each other and really be talking past each other. Example: Three instructors, three groups of students, three different agencies. Each group believes it is in Tobermory to do a "Deep Air Dive". They're even in line-of-sight of each other. One group is doing the Arabia, in 110', the second is on the Forest City, in 153', and the third is going God alone knows how many feet deep off the Dufferin Wall. Which group is doing "deep air"? The upshot was that a lot of people do stop at 130' under less-than-ideal conditions (overhead/cold/low-viz), quite a lot of people will do 160' under good conditions, a handful will do 180', and Rich Pyle said that under perfect conditions (openwater/warm/clear/prior experience) 200' might still be reasonable. Nobody advocated anything past that. We never did settle whether we meant the words "deep air" as up to a limit or beyond it; maturity in this area requires a willingness to draw the line for yourself shallower than the next guy draws his. For whatever it's worth, I propose the following terminology for different flavours of deep air: up to 5 ATA / 132' : Recreational Deep Air rounded off to 130', even PADI does this. The caving rules draw the line on air here too, since you need such a clear head. 5 to 6 ATA / 165' : Advanced Deep Air a lot of divers do this zone, at least in open water, with IANTD/TDI approval. Time to start moving to trimix, though. 6 to 7 ATA / 198' : Extreme Deep Air getting really serious; you'll find G3 doing his 190' deco stop on air, with a trimix reg ready in hand in case anything happens he wants to think about, and maybe you'll find Rich collecting fish down this far too. NOT for the neophyte. Under most circumstances you want to be off air and onto trimix going this deep. beyond 7 ATA / 198' : Fucking Deep Air maybe rounded off to 200', this is about the line where I don't care what your name is or what you think you're doing, if you're going past this mark on air I'm not buying your excuses. IMHO the biggest reason why people ignore diatribes against "deep air" is that these people dive the Advanced zone all the time, never have any problems, and hear something that's really aimed at divers in the Expletive-Deleted zone, and think ha, it's really not that bad and ignore the doomsayers, and then one day they venture deeper and boom. In that Advanced zone, yes there is a nonzero risk, and yes, there's longterm damage, but it's not the bigtime killer that the deeper zones are. All deep air cannot be lumped together. -- Anthony DeBoer http://www.onramp.ca/~adb/ adb@he*.re*.or* (here) adb@ge*.co* (work) #include "std.disclaimer" -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send list subscription 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]