Nitrogen Narcosis - Deep air dives

[John Bantin]

Some people experience narcosis at quite shallow depths. My experience of doing 55m+ (180ft +) regulator comparisons over two decades using air (the most problematic gas) for UK Diver Magazine is that I had always to be careful to choose participating divers who were unlikely to be affected by narcosis at that depth because they often did it (ie experienced deep divers.) In every case, my test divers wrote coherent notes on the performance of each regulator at depth, which corresponded with the findings of others - so I was confident of the veracity of the tests and the absence of narcosis with them at that depth. Originally, I took photographs on a Nikonos V with film while the tests were undertaken and found that I was able to be proficient with the techniques needed so I guess I too could handle it. (Later digital cameras made it an almost thoughtless process!) Some people can go very deep without experiencing narcosis (Bret Gilliam and Joe Odem come to mind). When we first dived the wrecks at Bikini Atoll (180ft), we only had air. There is no rule. Narcosis affects different people in different ways.

 

[John Bantin]

I should add that my good friend Rob Palmer said he enjoyed the cosy feeling of narcosis and repeatedly dived to 120m (395ft) deep on air - until it killed him. I wrote this in 1999: Get it wrong and you're dead

 

[NAUI Wowie]

Another Carribean island experience.

Cold water buddy came down to visit. A "narcosis doesn't effect me" diver. Agreed to cruise the wall at 120ft. Side by side, myself slightly behind him we descent.... He continues dropping past 120. He starting breathing heavily and finning headdown into the abyss. Unresponsive to hand signals. I shadow him till 178ft where I decide he's gone deep enough and something is wrong. Get him by the tank valve and bring him back to 120. He comes back to normal.

After the dive he talked about a strong down welling current and how he had such a struggle swimming up against it. Asked where I was and how I didn't feel it. Didn't recall forgetting which way was up or me hauling him back to the shallows.

That's my most extreme example I've witnessed of a form of narocisis.

The subtler forms I feel are just as likely to be deadly in an incident and go unnoticed.

(I still deep air dive personally)

Cameron

This frightens me as I do most diving with insta buddies in P.I. cebu and also mexico.

 

[NAUI Wowie]

I should add that my good friend Rob Palmer said he enjoyed the cosy feeling of narcosis and repeatedly dived to 120m (395ft) deep on air - until it killed him. I wrote this in 1999: Get it wrong and you're dead

The scariest part of that article you wrote is that at almost 400 feet he was waving others down to join him. If any others had...

 

[Landlocked123]

Deepest we have gotten to is 145 at the local quarry which we are still trying to map out... 8 dives below the 130 mark.. each at incremental depth .. 1-2 feet incremntal only on each... I have been doing math exercises which my buddy puts on my slate both pre dive and at depth... tracking the findings... my goal is to get to 30 dives and do a full report on it... I am seeing what I deem to be very minor impairment. On one dive I got one answer wrong out of 6.. i was subtracting negatives... .. I just am not seeing this impairment that everyone is talking about yet I know its there maybe just around the corner. We set 150 as the max bottom for air and we will bottom out the quarry at 220 in about 2 years following further training and certification to Trimix

 

[northernone]

Deepest we have gotten to is 145 at the local quarry which we are still trying to map out... 8 dives below the 130 mark.. each at incremental depth .. 1-2 feet incremntal only on each... I have been doing math exercises which my buddy puts on my slate both pre dive and at depth... tracking the findings... my goal is to get to 30 dives and do a full report on it... I am seeing what I deem to be very minor impairment. On one dive I got one answer wrong out of 6.. i was subtracting negatives... .. I just am not seeing this impairment that everyone is talking about yet I know its there maybe just around the corner. We set 150 as the max bottom for air and we will bottom out the quarry at 220 in about 2 years following further training and certification to Trimix

Glad you're enjoying your dives. As mentioned up thread, doing math calmly underwater does little to nothing to indicate narcosis levels or demonstrate what could well be a deadly level of impairment in case of a stressful situation. You're discovering this for yourself now but it sounds like you attribute it to thinking you aren't narced?

Concerned,
Cameron

 

[sea_ledford]

I am seeing what I deem to be very minor impairment. On one dive I got one answer wrong out of 6.. i was subtracting negatives... .. I just am not seeing this impairment that everyone is talking about yet I know its there maybe just around the corner.

Do a good 15 second sprint at depth and try again.

 

[Landlocked123]

So I am simply trying to determine for myself how impaired I actually am. Instead of opinions of others as to how narced I should be. So far I am seeing no major symptoms of narcosis. Couple of things. We are using a shotline, easy up and down. Staying only 1-2 minutes at depth, well short of NDL's, and dong NO WORK whatsoever. Its quarry diving so no currents. Its a very controlled setting. We continue to add small task loading a bit at a time. Zero concerns thus far. Would I do this dive in the ocean where there are currents and other variables... Nope... this was the dive from 2 weekends ago ... Hope you like AC/DC

 

[northernone]

So I am simply trying to determine for myself how impaired I actually am. Instead of opinions of others as to how narced I should be. So far I am seeing no major symptoms of narcosis. Couple of things. We are using a shotline, easy up and down. Staying only 1-2 minutes at depth, well short of NDL's, and dong NO WORK whatsoever. Its quarry diving so no currents. Its a very controlled setting. We continue to add small task loading a bit at a time. Zero concerns thus far. Would I do this dive in the ocean where there are currents and other variables... Nope... this was the dive from 2 weekends ago ... Hope you like AC/DC

At the risk of being redundant, until you have the contrast of a few breaths of trimix (easy to do) or problem solving under duress you'll be unable to self diagnose in a meaningful way.

I'll try to explain my concern another way as someone who regularly still dives deep air: I'll comfortably claim I've been clear without symptoms of narcosis at 268ft and minority impaired deeper, able to easily handle any problem solving puzzle I could dream up... That doesn't mean another day I've not been badly narced at 160ft. Or even that it was a factor far shallower for me in different conditions. That also doesn't mean my self assessment is remotely accurate.

For myself I find an unexpected problem the clearest test for narcosis, unfortunately failing that test has been fatal for many who take it. Trying to fix a tangled reel after a minute breath hold generally is my go to benchmark to see how susceptible I am on a given day. It's only a small percentage of the narcosis experienced in a high stress situation, but gives me a personal reference.... I'm better at math when narced.

Cameron

 

[Landlocked123]

I get everything you are saying and this is great input and I appreciate you sharing. The goal is Advanced Nitrox and Deco in the spring... then at least 300-400 dives ( I do roughly 150 a year limited by no dry suit) in that 100-150 range which I believe is the TDI limit of the cert. Then and only then will it be Trimix and on from there. For now I am limited to air. I stopped diving Nitrox years ago.. There is nothing I have not seen at the local area quarries that I need to spend that much time down there for. We are faced with a near zero viz layer from 70 to 110 so the only diving below 70 is past 110 unless one wants to wander in 6 inch viz.. Finding deeper good viz water was the reason we even began this project. So for now in order to see anything new and do some exploring its deep air. It is what it is. As I said. 150 is max bottom depth. I undertook this process of trying to determine my tolerance as a way to be safer about it. We started at 115 this summer and went from there. its all about baby steps. The reel exercise sounds interesting. Yeah we carry 5 cutting devices between the two of us and the visibility down there opens up superbly as you can see...