jimdiverman
Contributor
Actually, Grazie, PSAI intentionally takes you down to 240 ft (for a very short time) in courses designed to test your ability to handle being narced. I believe that is Level VI in PSAI Narcosis Management course. Of course you take Level III through Level V first. Diving on air, the partial pressure of Oxygen reaches 1.6 at 218 feet, so you are really pushing things below that for extended periods of time. Actually, before there was trimix (not that long ago), people routinely dove on air to deep wrecks like the Andrea Doria. I am going the PSAI route at this time. I have only completed IANTD Adv. Nitrox and Deep Diver, and PSAI Adv. Nitrox Diver. I am scheduled for twin sets and cavern this month at Dive Outpost right before DEMA. I will let you know how it goes, but I think the instructor makes a big difference in what you get out of any of these courses. I find that all of the literature leaves a lot to be desired at this level. I think the best way to find a good instructor is to talk to other technical divers who have actually been through the courses and ask them for names.