Deep diving advice that goes against conventional thought?

[tracydr]

I usually hold my breath for a really long time on the surface before doing my 250 foot air dives. That way I don't have anymore oxygen in my lungs to prevent ox-tox. Come to think of it, I don't remember doing any of those dives. Hmmm.

Oxygen and nitrogen is always in our bodies, regardless of how much we actually breathe. It's a matter of partial pressures and time that determine the amount of oxygen and nitrogen diffusing the blood-brain barrier. I don't believe skip breathing would make enough difference to even be noticed.
Sheck Exley dived frequently to 300 feet on air but he wasn't a mere mortal.

 

[dsr30]

I read about 125 posts into this thread, all I can say is wow! Akimbo, DCBC, BobDBF, Danvolker, etc, I always like to hear from guys like you who have pushed limits, are experienced and don't have this "don't do it, you'll die" mentality about diving. It amazes me how closed minded some people are, because they can't do it, never did it or were told they shouldn't do it, it can't be done, they don't and tell anyone who'll listen that they'll die if they attempt to do it. They accept what they've been fed and regurgitate it even though they're countless examples of the "you'll die" activity being performed without incident. Everyone is different, different physical and mental abilities and capacities, different personal limits, etc. I wish I had some people like you guys to dive with and to pick your brains.

 

[drrich2]

I've been enjoying the thread. A brief little snippet from Akimbo's post high-lights a concern I have:

True but if you slowly working your way deeper on repeated dives to discover your individual narcosis threshold, the answer is irrelevant.

I'm not anti-deep air, and much of what's in this thread is over my head. Drawing on what I've learned from others on the forum, I'm curious about the practical feasibility both of learning your narcosis threshold, and cultivating the ability to handle being narc.'d with a reasonable margin of safety. Much as a drinker considering driving at a given speed in given conditions might weigh whether he felt sober enough, assuming a scenario where he was the only person in potential jeopardy.

If I understand correctly:

1.) People may not realize they're narc.'d until they try to do something challenging, or reflect on a dive after the fact (e.g.: why didn't being that deep the long alarm me?), or a dive buddy describes abnormal behavior to them they don't even recall. But at the time, they 'felt fine.'

2.) Narcosis susceptibility in an individual varies across different dives.

3.) If I understand correctly, narcosis on very deep dives can sometimes exacerbate pretty quickly once it becomes symptomatic.

4.) Most people don't have access to the testing equipment, testing and professional supervision that's guided DCBC's knowledge base.

5.) I suspect many divers doing a lot of deep air work are so seasoned at diving that much of it is, figuratively speaking,' like 'muscle memory,' and requires less mental 'bandwidth' to execute than it would for someone newer. In other words, let's say DCBC and I each did a 150' deep air dive at the same site and benign conditions (let's say the Belize Blue Hole). Now, putting aside demographic variables such as age, fitness, how acclimated to narcosis he may be through much greater experience and diving education, etc..., consider that I'm going to have to think about what I'm doing more than he will; common dive tasks will be less instinctive for me. So if we were equally physically susceptible to getting narc.'d, odds I'd get messed up may be much higher, because I'm more task-loaded even though we're doing the same thing.

Richard.

 

[Akimbo]

… I'm curious about the practical feasibility both of learning your narcosis threshold, and cultivating the ability to handle being narc.'d with a reasonable margin of safety. Much as a drinker considering driving at a given speed in given conditions might weigh whether he felt sober enough, assuming a scenario where he was the only person in potential jeopardy...

Unfortunately, alcohol intoxication is the only experience that most of the population can relate to. I cringe when I hear the alcohol and Nitrogen Narcosis analogy though. They are quite different in many ways.

Nitrogen Narcosis also isn’t LSD or the weed depicted in Reefer Madness. However, you have to physically prove that to yourself. Reading the Internet isn’t adequate. Imagine yourself as an early diving pioneer. You know that Nitrogen Narcosis exists and have read the classics stories — like the copper helmeted heavy-gear divers annoyed by his hose and trying to cut it and the story in Cousteau’s The Silent World about a diver trying to buddy breathe with a fish (both of which are “literary tools”).

What plan would you devise to discover human limits and meet your safety criteria? My guess is baby-steps and reliable dive buddies are involved.

 

[Diver0001]

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A ScubaBoard Staff Message...

I've split out all the off-topic stuff about Exley, etc. to this thread: http://www.scubaboard.com/forums/ad...-split-deep-diving-advice-exley-side-bar.html

Please try to keep the current thread on topic.

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[kr2y5]

Thanks again, Akimbo and DCBC, for your informative replies.

What is gullible is accepting the doctrine without analyzing the education they must have been exposed to

I wholeheartedly agree... learning requires critical mindset and bi-directional communication!

I suspect many divers doing a lot of deep air work are so seasoned at diving that much of it is, figuratively speaking,' like 'muscle memory,' and requires less mental 'bandwidth' to execute than it would for someone newer.

Unfortunately, alcohol intoxication is the only experience that most of the population can relate to.

Gary Gentile in "The Technical Diver's Handbook" uses the analogy to a camera taking photos at a high-speed, and the diver's brain selectively processing some of them and discarding others. A more experienced and/or more focused diver will, according to that metaphor, be more adept at prioritizing the snapshots to "process" further (e.g., be more diligent in monitoring air consumption), resulting in improved performance during the dive. Other sources I've read seem to agree with this... that it is not as much of a true physiological adaptation, but the experienced diver's ability to much better utilize his limited processing "bandwidth" for the most important tasks, such as following all the proper procedures, etc.

What plan would you devise to discover human limits and meet your safety criteria? My guess is baby-steps and reliable dive buddies are involved.

My plan involves taking up technical training and mentoring, and (hopefully) getting thoroughly narced under a watchful eye of a seasoned instructor. I have yet to experience symptoms that I could definitively attribute to IGN, which contributes to my overall feeling of uneasiness around it. I would readily sign up for an exploratory chamber ride if one was being offered nearby. That would be a much better use of the money I had paid for my AOW (my performance on puzzles, like writing my name backwards, was better at depth than on the surface, but that was my 2nd time doing them, so we did not measure anything besides adaptation).

 

[tracydr]

I've been enjoying the thread. A brief little snippet from Akimbo's post high-lights a concern I have:


I'm not anti-deep air, and much of what's in this thread is over my head. Drawing on what I've learned from others on the forum, I'm curious about the practical feasibility both of learning your narcosis threshold, and cultivating the ability to handle being narc.'d with a reasonable margin of safety. Much as a drinker considering driving at a given speed in given conditions might weigh whether he felt sober enough, assuming a scenario where he was the only person in potential jeopardy.

If I understand correctly:

1.) People may not realize they're narc.'d until they try to do something challenging, or reflect on a dive after the fact (e.g.: why didn't being that deep the long alarm me?), or a dive buddy describes abnormal behavior to them they don't even recall. But at the time, they 'felt fine.'

2.) Narcosis susceptibility in an individual varies across different dives.

3.) If I understand correctly, narcosis on very deep dives can sometimes exacerbate pretty quickly once it becomes symptomatic.

4.) Most people don't have access to the testing equipment, testing and professional supervision that's guided DCBC's knowledge base.

5.) I suspect many divers doing a lot of deep air work are so seasoned at diving that much of it is, figuratively speaking,' like 'muscle memory,' and requires less mental 'bandwidth' to execute than it would for someone newer. In other words, let's say DCBC and I each did a 150' deep air dive at the same site and benign conditions (let's say the Belize Blue Hole). Now, putting aside demographic variables such as age, fitness, how acclimated to narcosis he may be through much greater experience and diving education, etc..., consider that I'm going to have to think about what I'm doing more than he will; common dive tasks will be less instinctive for me. So if we were equally physically susceptible to getting narc.'d, odds I'd get messed up may be much higher, because I'm more task-loaded even though we're doing the same thing.

Richard.

It's a fairly well known that diving repeatedly and going slightly deeper on " build-up" dives can significantly lessen the effects of narcosis.

 

[Akimbo]

…My plan involves taking up technical training and mentoring, and (hopefully) getting thoroughly narced under a watchful eye of a seasoned instructor...

That strategy has a lot in common with what the Navy does (did?) with First Class Diver students… and works pretty well.

The US Navy ran all of us to 285' in a chamber in First Class Diving School, once dry and once in a wet pot in Mark V deep sea gear. We were also learning to operate the chamber so we had the opportunity to see how narcosis affected us and others. Narcosis didn’t sneak up on anyone given the depth and training; we all knew we were going to be compromised.

I think it is fair to say that mental preparation and being self-aware makes a huge difference in performance. We knew that we were not functioning normally and could compensate to some degree on familiar tasks like tying knots and putting together pipe puzzles. Vision, dexterity, and speech were all affected in different ways. Problem solving was harder to measure during such short exposures but even the cockiest of us reassessed our invincibility.

I have not seen studies that confirm or deny the phenomenon but nearly all commercial divers and supervisors I have spoken with believe repeated short-term deep air exposure increases narcosis tolerance and improves performance. Most people I have spoken with think that nitrogen narcosis is quite different than being impaired by alcohol. Mental and physical control under narcosis is much better.

I can see how narcosis can be much worse if you have never experienced it and it sneaks up on you. It is a shame that chambers are so expensive to operate because it is such a safe way to learn about it.

I doubt you will get “thoroughly narced” unless you are extremely deep and your mentor or instructor is on mixed gas. You are more likely to hear reports that you were awkward or clumsy than out of your mind or unresponsive.

I never experienced or observed any radical Narcosis impairment like the old sea stories or divers heading for the Abyss. It was more like slow or sporadic mental processing and compromised senses. Vision, coordination, and sensations are affected most on me. It’s hard to say if hearing is affected since sound is attenuated at depth anyway, which adds to the distraction. It is as though my problem solving ability is much less impacted than all my inputs. I noticed that my lip mussels have always gotten somewhat numbed — on Scuba, in hats, or in a chamber. A lot of people describe metallic tastes.

Generally, and in my limited sphere of observations, divers are aware of their impairment and become deliberate and methodical. They often miss stuff happening around them, either because they are highly focused and/or because their senses are compromised.

 

[boulderjohn]

It's a fairly well known that diving repeatedly and going slightly deeper on " build-up" dives can significantly lessen the effects of narcosis.

I don't think you worded it quite correctly. It should be "It's commonly believed that diving repeatedly and going slightly deeper on " build-up" dives can significantly lessen the effects of narcosis."

I am not sure that there is enough evidence of this to use the word "known." Perhaps you could cite some evidence beyond common belief.

---------- Post added March 16th, 2014 at 09:25 AM ----------

I never experienced or observed any radical Narcosis impairment like the old sea stories or divers heading for the Abyss. It was more like slow or sporadic mental processing and compromised senses. Vision, coordination, and sensations are affected most on me. It’s hard to say if hearing is affected since sound is attenuated at depth anyway, which adds to the distraction. It is as though my problem solving ability is much less impacted than all my inputs. I noticed that my lip mussels have always gotten somewhat numbed — on Scuba, in hats, or in a chamber. A lot of people describe metallic tastes.

As I said in my first post on the topic, I am told that the effects of extreme narcosis are much different from what most of us have experienced.

In my conversations with Bret Gilliam, he described an effect at very great depths akin to blacking out. As I said earlier, he believes Sheck felt that coming on and tied himself off in the belief he would come out of it.

The death of Opal Cohen in Cozumel a couple of years ago is attributed to narcosis. (http://www.scubaboard.com/forums/cozumel/395192-scuabamau-diving-accident.html) She and two buddies attempted a bounce dive on air to 300 feet, but when they hit 300 feet, she kept going and was not turned around by a pursuing buddy until she hit 400 feet. The common belief is that she was so thoroughly narced that she did not know what she was doing. When I was in Cozumel not long after, though, a professional with another dive operation said she blacked out at 300 feet. Whichever is true, she was awake enough to participate in 3-way buddy breathing during the ascent and did not die until lengthy chamber treatments. (The 2 who went to 400 feet were out of air in their single tanks and shared with the one who stayed shallower).

 

[danvolker]

Here are two instances of the narcotic "blackout"...

One one dive we did in 95 or 96, on air at about 270.....The drop by the boat had us down current from the wreck, causing about a 100 foot swim against a strong current to reach the wreck....This was not terribly hard for me as a Palm Beach diver, as with all the high current hunting I had done, my instinctive reaction was to get down on the bottom, and stop swimming, and start a slow, hand over had and methodical traverse to the wreck....which was working just fine, until one of my buddies a little ahead of me began swimming off at a 30 degree angle away from the wreck....with nothing of any interest in front of him...since he was buddied to me, I followed, and ultimately after about 30 seconds of this very wrong direction, that was now more like 90 degrees off....I put on a burst of swim speed and hard," hand over hand" pulls...and caught up to him--though now maybe 2 minutes into swimming sideways and ultimately with the current--so no where near the wreck anymore........and on catching him, I grabbed his fin very hard with a big tug.....He stopped, looked back at what had just grabbed him so hard that his forward motion had stopped....and he had this weird look like--what just happened...and where are we....he then did a quick look around, saw that we had deviated way to far away from the wreck.... I pointed to the computer--time...and then at the surface, and he processed this just fine, and he agreed to ascend.....So I am discussing this as a blackout while still swimming.

On another deep air dive a few months later, on the RbJohnson Cory'n Chriss ( max depth 280), We dove in 3 groups of 2 with close DIR friends, but the boat also had a couple of other buddy teams, including one with a "girl" named Ashley, and a guy named Lichtenstein.....they were not with us, but they had agreed to follow the general dive parameters, of a 25 minute max bottom time, and hour long deco--and we would be doing a second dive after 2 hours of interval, at a 130 foot site we liked.
We did our dive mostly on the lower wreck,mostly at around 270 or so....and we collected ourselves and headed up at 25 minutes, saw Ashely and Lichtenstein in the rigging on top of the RB at around 210 or so, in the middle of a massive swarm of Amberhack they were apparently engrossed in...George pointed at his computer to Ashley as we went by, and she nodded....and then we were far above them....

At our 50 foot stop, we kept waiting to see the 2 of them show....10 minutes later, at our 40 foot stop, George and I were making hand gestures about what to do about the 2 missing, and George and I were about to go back down, and have Bill mee keep everyone else doing deco...and obviously get the attention of our safety diver....
Just as we began our re-descent, there was Ashley and Lichtenstein.....they made some apologetic hand signals....and George and I were both disgusted with them.
So we do our whole deco, and then are on the boat...and Ashley and Lichtenstein are doing deco forever....and in fact, the extra 10 minutes at 225 WAS a big extra deco penalty....Of course, everyone was pissed because these two divers ignored the plan, and now we would all miss our 2nd dive...it would be too late....Ashley gets out in another 30 minutes, and explains that Lichtenstein had become unresponsive....she kept pointing to the surface, he would look at her...and just keep looking on at the amberjacks....She said she at first just thought he wanted a little more time...and she was OK with this, then after a few minutes, she realized something was wrong with him...Finally she got him to "wake up" and really see her...and see the computer...and they both ascended with haste to the first stop depth...

When Lichtenstein finally climbed onto the boat, we had already decided this guy would not be allowed to dive with our group ever again...and then, just as the impatient desire to have the boat up on plane was being satisfied, we saw the Captain, Jim Mimms, slowing the boat down to a stop...and then Lichtenstein jumping back into the water.....And of course, some of us were mumbling under our breath.....until we found out what was going on....Lichtenstein had been so narced and blackedout, that he had Sh*t himself....his wetsuit was full of sh*t and he got back in to rinse it out!!!!!!
Apparently, if you get one of these narc blackouts, you can lose control of your bodily functions!!!!
And no, I never saw him on a dive boat again