Deep Air Diving - thoughts

[Thalassamania]

You can do a task well, while affected by narcosis, by rehearsing it 100 times, yes.
The problem arises when you have to do something that is NOT rehearsed and unexpected.

Bold: you are never immune to narcosis. It is a physiological mechanism you have no control over. I assume you didnt mean literally immune?

I was not being literal, but I was being littoral.

 

[sheck33]

I was not being literal, but I was being littoral.

Alrighty then

 

[Hank49]

Okay - I've got some preconcieved notions about "deep air" diving - (i.e. 130-180 feet) -


With time, and experience, repetitive dives teach you how to operate in that type of environment, I would even go so far as to say that your body begins to tolerate that type of stupor, and you learn to perform better at deeper depths with successive dives.

but am I wrong to surmise that you get better with each experience?

Just my ideas - please those that have "been there, done that" chime in...

Thanks!

D.

In my experience (200ish dives over 50 meters...30-40 over 65 meters) it's inconsistent. Some days I was really in the twilight zone and others, even one at 72 meters, I felt....well, normal? Thal said it too, you just don't know, and just because you didn't get narced yesterday out of your mind, doesn't mean you won't today.

 

[sheck33]

In my experience (200ish dives over 50 meters...30-40 over 65 meters) it's inconsistent. Some days I was really in the twilight zone and others, even one at 72 meters, I felt....well, normal? Thal said it too, you just don't know, and just because you didn't get narced yesterday out of your mind, doesn't mean you won't today.

No, it isnt. You are impaired on any deep air dive, whether you think you are or not is irrelevant. The physiological mechanism of narcosis doesnt have 'days off'. It is like saying I can drink a bottle of vodka on Saturday and not be affected while the same bottle incapacitates me on Sunday.

How well you function depends on how second nature to you the task you have to accomplish is. The real test comes when things go wrong. That is why narcosis is so deceptive, you think you are just fine when you are not. But this has been beaten to death already.

 

[Kevrumbo]

From The Last Dive:

We couldn't get the debris out of our way inside the wreck, and it was all silty, so we couldn't see anything . . .Then we saw the outside light every once in a while. It was so confusing. It felt like I was dreaming, and like I was hallucinating. It was like the wreck was grabbing me, trying to pull me further back into it. We were just crazy to dive this thing on air. . . [The late Chrissy Rouse, before painfully expiring in the Recompression Chamber]

Even the author's deep air bends accident as described in the book is just as infamous, and a harbinger of what would tragically befall the Rouses' --a classic case of the deadly combination of Nitrogen and CO2 Narcosis experienced at depth, and the resulting cascade of problems it can initiate. . .

 

[Hank49]

Sheck33, I agree. But certainly, sometimes you feel like your eyes are being pushed back in your head and you're looking through a tunnel. And sometimes you just don't want to be there. Other times, you don't feel that way.

 

[sheck33]

Sheck33, I agree. But certainly, sometimes you feel like your eyes are being pushed back in your head and you're looking through a tunnel. And sometimes you just don't want to be there. Other times, you don't feel that way.

Absolutely. One's perception of it varies wildly.

 

[peterbj7]

I recall listening to a debrief on an English dive boat. The instructor had just conducted a Deep Air dive with a student, down to (I guess) 50 mtr or so. The student was on air, the instructor on trimix.

Instructor - "after we agreed we were going to ascend, how long do you think it took you to send up your DSMB?"
Student - "about a minute and a half"
Instructor - "you actually took well over 7 minutes, which shows why you need to move onto trimix as soon as possible!"

 

[DA Aquamaster]

From The Last Dive:
Even the author's deep air bends accident as described in the book is just as infamous, and a harbinger of what would tragically befall the Rouses' --a classic case of the deadly combination of Nitrogen and CO2 Narcosis experienced at depth, and the resulting cascade of problems it can initiate. . .

That is a bit of an extreme case - penetrating the U-869 at 240' on air with a very aggressive dive plan. That had bad written all over it and would have been pushing it even on trimix.

 

[Kevrumbo]

Then here's a deep air success story --the discovery, rediscovery and cataloguing of the Wrecks of Truk Lagoon by Kimiuio Aisek and Klaus Lindemann-- more ascribable though IMO to careful planning, repetition and "progressive penetration" over time in the relatively benign waters at Chuuk; rather than attributing the build-up of a "body tolerance" to narcosis as the OP would surmise. . .