Posted by TDI_2 on June 17, 2002 at 11:00:29:
In Reply to: Re: PADI's rules posted by Eric S on June 14, 2002 at 20:03:20:
A 120 fsw dive on air for an experienced diver of several years is normally not a big deal. Normally. Especially if its a short duration dive, 5 or 10 mins max bottom time, and you dont repeat it again that day.
If you really cant get nitrox, then you are stuck in an air diving environment. That means slow ascents, really slow, 15 to 30 fpm, and long safety stops, 3 to 5 mins, with the first stop at one-half your max depth for a minute or two, and the final stop at 15 fsw maybe for a full 5 mins, in addition to conservatively limiting your NDL times at the depths that you go.
IANTD in their tech literature coined the phrase "all diving is decompression diving." Thats a good thing to always bear in mind, for safety's sake.
I dont know of any study that specifically focuses on air diving limits where nitrox is not available. It is the current thinking of many tech instructors that with the development of nitrox and trimix, that pushing the limits of air diving beyond about 100 fsw is unnecessary.
I do know several friends who have diving stories that go "I didnt ever get the bends until ... and then I had to go to the chamber." The object of the dive safety game is to minimize or eliminate the likelihood of another chamber story.
If you dive a lot on air deeper than 100 fsw then some tech training that teaches you to sling a nitrox tank for egression would add to your safety factor. Thats what PADI calls "tech rec."
I skipped PADI's tech rec and went instead into TDI's tech regimen of advanced nitrox, staged deco, advanced deep air, and basic trimix. That gives me a lot of training and flexibility for dives up to 200 fsw. I highly recommend it.
There are tech diving stores in San Jose, Santa Cruz, Monterey, and I believe in Sacramento. If you are going to dive over 100 fsw a lot, they are well worth it. They will give you a totally new perspective on diving, that you never had before.
Its not about pushing the NDL limits. Its about diving safely to whatever depth you have chosen to go. Thats my new perspective.
The training is available, and the classes are fun. You might as well take the courses and dive more safe. Im glad I did.
One reason I really love freediving is that all those rules and factors are gone. In freediving you are really free. A good freediver is an ever safer scuba diver. And I know that you are both a good freediver and scuba diver Eric. No flames here, buddy!
By the way, I have recently extended my glorified rock picking from 15 fsw to 25 fsw. My current freediving comfortable maximum of 25 fsw is now close to seahunt-MikeB's minimum! All things are relative. :)