PSAI Narcosis Management course - 73m on air

[Tortuga68]

No notes or mention above addressing this most important and potentially deadly caveat which follows below:

Deep Air with increased Gas Density, Flow Viscosity & Work-of-Breathing; then throw in Physical Exertion or a Stress Condition, resulting in overbreathing the regulator (also can result from just breathing a malfunctioning "wet regulator") --all leading to the Vicious Cycle of CO2 Retention and sudden Narcosis. Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . .

Firstly, it was covered in the course materials, secondly when you're going up and down a line hanging off a float there's no need to kick and thirdly I thought the implications of exertion on deep dives were relatively well-known amongst technical divers

 

[Kevrumbo]

Firstly, it was covered in the course materials, secondly when you're going up and down a line hanging off a float there's no need to kick and thirdly I thought the implications of exertion on deep dives were relatively well-known amongst technical divers

It's worth repeating & emphasizing again anyway -for all divers- the negative implications and potential overwhelming cascading effects:

The Tragedy of Yuri Lipski

 

[Dr. Lecter]

Single tank at nearly 300'? lol Yeah, that's a deep air death for sure

 

[Nasser]

If you read a more thorough description of the entire dive, you learn that Ormsby had problems from the start, and he was separated from the others when he got tangled. How he got into that nest of cables in the first place is a potential reaction to narcosis, a crashing, blundering entrance I read about some years ago in a source I cannot find now.

It could have been Deep Descent - Adventure and Death Diving the Andrea Doria by Kevin McMurry. That has a fairly thorough description of what went on during Ormsby's dive and the subsequent body recovery attempts made by Gary Gentile and Billy Deans.

 

[DiverGuam]

Hey a question for whoever....

How is the availability of deep dives in your neck of the woods? I could do 73m air dives every day off the daily boat. I do do 60m/66m air dives regularly off them. (I am with DevonDiver on the general idea of 1.4/1.6, but I have also done dives well over those limits on 100% o2. Navy divers are not currently trained to do 66ft on 02 rebreathers, apparently, but that was standard just 20 years ago).

To Tortuga68 how is the deep diving availability in Puerta Galera? What is the deepest you could dive say tomorrow on a regularly scheduled boat trip?

How would you feel about diving somewhere you could not see the surface from 60m/66m/73m on air? Or for that matter, 100m on Trimix in the same situation?

 

[Tortuga68]

CO2 buildup can be a problem in any working dive, it's not specific to deep air dives.

DiverGuam: The Verde Island passage off PG is very deep and was the site of John Bennett's (then) world record (deep scuba) 308m dive in 2001; so there's plenty of deep diving within easy reach. There's not much to see below about 85m though. Although the viz here is generally quite good you usually can't see the surface below 30-40m... personally I don't feel the need to maintain visual contact with the surface on any dive.

 

[Tigerman]

All other things aside, seeing the surface can actually give you a false sense of security as it may be further away than you think it is...

 

[DiverGuam]

Your point is well taken, because one of the places I do deep air dives all the time is a place where a fair number of people die, probably due to narcosis induced failures, probably because clear water fools people. (Thread regarding a recent death and discussion of it here: http://www.scubaboard.com/forums/accidents-and-incidents/502079-dive-accident-guam.html )

For me, the real advantage of seeing the surface is absolute navigation back to the boat, and not needing lights to do anything.

I would do a lot less deep air diving if navigation became something I had to actually think about, because I am tied to doing my dives within the time that fun diving groups are doing their dives, and I cannot make the boat wait, and I have to follow the boat if it leaves the mooring to grab divers, or swap moorings, etc.

Actually, I would be able to do a lot less deep diving if it involved really any prep work, because I am just jumping on a boat that's already going out and doing my dive at wherever the boat goes. (All of my deep diving is solo for the same reason. Day off= Deep air dive with whatever tanks I have filled, at wherever the boat is going.)

 

[Remy B.]

Tortuga68, when you did that course, did you ask your mentors what was the fail rate of the tests or where most of the divers stopped and didn't want to continue ( reach their limits ) or were clearly not capable of going to the next level/not allowed.

For Example

Level 4, from 10 divers 2 fail
Level 5, from 10 divers 4 fail

And what about the time of exposure, common standards recommend to not exceed PPO 1.6 or to not expose your self to lover PPO's but for extended times, the limit was exceeded but was their a particular emphasis of not spending to long down there since now that the recommended limit was exceeded more danger was present is continue for a longer period of time exposure to that PPO

To bad this thread got so FU like most threads in SB, all what I understood is that Tortuga68, just wanted to experience and learn Technics that may help him in an unlikely/unlucky event, I don't see nothing wrong with that, he was just sharing his experience, he is not advocating to do those deep dives, he did not say air is better than Trimix, he just didn't know trimix at the time, probably by now he does since it was more than 5 years ago.

 

[Tortuga68]

As I replied to your PM, I didn't ask and don't know about the "fail rate" as it wasn't of interest to me. I would imagine most divers who took the course stopped at/before a level that exceeded their personal tolerance for PP02 exposure based on the bottom times required, since that would be the rational choice. MOD should be considered based on activity and exposure; the bottom times for the course are relatively short.

I am now Advanced Trimix certified FWIW but continue to dive "deep air" up to 65m in the warm, clear, bright waters of the Philippines where I now live. I'm looking forward to visiting Truk Lagoon in September, and Technical Cave certification in Mexico next year; both of which I plan with an END of 30m. As I have always said, your dive plans should be appropriate to your training, experience and environment.