PSAI Narcosis Management course - 73m on air

[AfterDark]

Tortuga, thanks for the thread it is a interesting read and you really know how to draw out the A-holes! It's like some read a different thread then posted on this one!

 

[The Chairman]

Sorry I came into this discussion late... the name of the class is pretty enlightening: Managing Narcosis. Too many people believe that they can become impervious to narcosis and that's a lie. It's also why the class is done in increments. If you start to get to fuzzy on any dive, that ends the progression. It's one way to determine your air limits.

The course was created at 40 Fathom Grotto by Hal Watts. I have known Hal since 1969 (bought my first set of fins from him) and remember a number of his exploits throughout the years. If you ask Hal about the high PPO2 of air at these depths, he'll look at you and smile and point out that the limits were based on mixed gas diving and not air. I know, because I asked him that very same question when the class first came out. Why does the class end at 70 meters? That's about how deep his Grotto is. Now it's being used as the deep diving facility for a commercial diving school. Would I descend to 240 ft on air? I have. I even remember the dive fairly well as with all my dives to 200+ feet.

 

[Kevrumbo]

General Caveat FYI:

On adaptation to Deep Air and Nitrogen Narcosis:
"Moreover, our results suggest that experienced divers can discriminate between the behavioral and subjective components of narcosis. . .It has been proposed that the intensity of narcotic symptoms could be used by divers to gauge the extent of performance loss (10). The present results indicate that this advice is inappropriate for adapted divers because the two components of narcosis [behavioral and subjective] uncouple in a direction that could lead to an overestimation of performance capabilities --a potentially dangerous situation. On the other hand, the question arises as to whether adaptation confers any benefits on the diver, since performance efficiency is not directly improved and could be overestimated. In this regard, it could be argued that a reduction in symptom intensity reduces the possibility that attention will be focused on subjective sensations rather than the task at hand."
From:
p.9, Hamilton K, Laliberté MF, Fowler B. Dissociation of the behavioral and
subjective components of nitrogen narcosis and diver adaptation. Undersea Hyperb
Med. 1995 Mar;22(1):41-9. PubMed PMID: 7742709.

 

[usmarinekurt]

Hopefully your instructor was on trimix!!

 

[The Chairman]

Hopefully your instructor was on trimix!

What's good for the goose is good for the gander. It's my opinion that nstructors should teach in the same configuration as their students. This would include gas as well as gear.

 

[ajduplessis]

Is that what you do on your dives...?

Go down a line and come back up...? Doesn't sound like much fun... no reef, no wreck, no swimming...?

Does not matter, he wouldn't remember anything in any case.

 

[rongoodman]

What's good for the goose is good for the gander. It's my opinion that nstructors should teach in the same configuration as their students. This would include gas as well as gear.

One of the reasons I walked away from a trimix class last year was the instructor's insistence in diving on air. If I screw up at 190', I want the guy watching out for me to have his head on straight.

 

[AfterDark]

Does not matter, he wouldn't remember anything in any case.

That's so lame. Can you back that up? I'm old school deep air diving. When I started deep diving there were no tirmix classes or deco classes for that matter. I've made many a deep dive on air. I remember everyone of them. You and others show little or no class with your baseless snide comments. You all show nothing but your ignorance. IMHO

 

[The Chairman]

One of the reasons I walked away from a trimix class last year was the instructor's insistence in diving on air. If I screw up at 190', I want the guy watching out for me to have his head on straight.

You're smarter than I look!

 

[DCBC]

Thanks for your comments Afterdark. It seems that criticism often comes from people who have little or no deep-air experience. I do however respect their right to choose the appropriate gas for them in any diving situation. It often seems to be the case that if their preferred choice conflicts with mine, that I must be an idiot...

I've taught mixed-gas helium since 1972. Do I prefer to dive Helium past 200 feet? Yes. Is it a requirement for me to dive to 200 feet? No. The fact is that Helium is not always available, nor is it always required on a deeper dive.

Not every diver has the same training, nor the same experience. Generally speaking, the greatest majority of sport divers should not dive AIR past 100 feet, but there are exceptions. That said, I would point out that the majority of all sport divers shouldn't dive past 150 feet using ANY gas. There is more to diving deeper than the gas you breathe.

Perhaps it's sufficient to say that the diver should not dive deeper than his training and experience allows and only when that diver feels suitable during the dive. Constant self-assessment is a requirement.