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Wot’s it like? Anyone got firsthand experience they can relay to a landlubber? Is the onset quite sudden? Is overcoming it as simple as ascending a few feet? How long for it to go away?
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Does a diver have a personal narc depth at which he is affected, and is that depth constant or dependent on other variables? Can a diver work to increase this depth?
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Can/do experienced divers “work through” narcosis and continue to descend despite recognizable symptoms?
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What means exist for getting around it? Do you need to breathe helium if you want to do, say, a 200 foot SCUBA dive? Or would that depth require too much air and a tank too large for a meaningful dive?
Never had it and don’t want to, but I can give you the PADI answers to your other questions (not sure how rooted in science it is, but it definitely errs on the side of caution).
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Each diver of course has their own level. However, the tables that divers use are based on a worst-case scenario of the average tolerance of hundreds of divers. Historically, the first tests were on fit US naval chappies, and tended to put lardass divers like me at risk, so they updated the
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We’re taught that there’s nothing you can do to work through it, and that once you’ve got it, you’re you’re incapable of rational thought - hence the buddy system.
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IIRC, ‘Nitrox’, a mixture of nitrogen and oxygen that differs from air, and various other different gas blends, can be used to alter the regular air balance of the two gases, to allow faster recovery times, and more depth tolerance. Not quite sure of the chemistry. There are also rebreathing mechanisms, and dual tanks that you can switch, and so on.
Oops. “so they updated them based on recreational divers. Based on depth and time, these give you the recovery time necessary between dives in order to avoid too much nitrogen in the blood.”
Been there, done that (long time ago). I used to be an active SCUBA diver. My deepest ocean dive, accompanied by an experienced dive master, was to 180 ft. It was a group dive, about 10 divers. We definitely experienced nitrogen narcosis. The stories I had heard about fits of giggles etc didn’t effect us-of course the dive master’s lecture before the dive would have sobered up a saturday-night-live comedian. As for what it feels like, the best description I can give is woolly. I certainly knew that I wasn’t clear-headed and wasn’t able to think straight. But since all we were doing was hanging around looking at the cliff (the water is over 5000 ft deep straight down, we went down the first 180 ft. Tongue of the Ocean Bahamas), it wasn’t a problem. No one felt like doing anything silly. We would have been in deep trouble (pun intended) if anything had gone wrong-but it was a simple dive.
It was a single tank dive. We had about 5 minutes at depth and just a few minutes (if I remember correctly) decompressing on the way up. Even sport divers such as ourselves could have performed simple tasks at depth, and the maximum depth-well standards are probably different now so I won’t guess. The key is if anything goes wrong the narcosis pretty much guarrantees you won’t be able to deal with the problem. If nothing goes wrong-you win!
I have never used mixed gases, but it is my understanding that HeOx mixtures are intended to avoid the effects of narcosis.
I don’t have a death wish.
Do you have a death wish?