Not diving to greater than 30m/100ft unless with helium

[Storker]

At the depths in question, maybe it's not so much "impairment" as just wanting to be able to think that much more clearly or to be able to rememb in minute detail what you saw down there.

This is downright contradictory to me. If you can't think clearly and/or can't remember your dive, I'd call that being noticeably and significantly impaired.

I'm not He certified, so I'm only using air or nitrox. I've got my own personal limits. And my limit is 30m. I've been deeper, but only under benign conditions. On a normal dive in my home waters, I can usually feel the narcosis starting to sneak up on me somewhere between 25m and 30m. I don't know if I'm particularly susceptible to narcosis, or if I've just got a sensitive radar WRT mental impairment...

 

[Lorenzoid]

I have done some pretty complex work in the 160-180' range without much concentration or the need for excessive preparation. I'm confident that I am not somehow "exceptional" since many people I have dove with have done the same. For me. 200-250' requires progressively more preparation and concentration but have never felt that I could not handle the unforeseen. The actual depth you personally react to these constraints is not important, finding them is.

You need to know your limits when diving in a soft or hard overhead environments. You never know when air or lean nitrox is all there is left to save your butt so you better have some idea how to manage the consequences.

I guess it's all about narcosis "management." It scared the heck out of me when I found in the AOW class that I was slower doing those puzzles on the Deep dive than at the surface. I don't care if I'm just a few seconds off--I would rather be at my sharpest if it's at all feasible. I suppose the alternative is to learn to "manage" the narcosis, but I'm not sure what that entails. I am inclined to believe helium would be useful beyond 100 feet. If only it were affordable for those 130-ft dives.

---------- Post added October 5th, 2015 at 05:18 PM ----------

This is downright contradictory to me. If you can't think clearly and/or can't remember your dive, I'd call that being noticeably and significantly impaired. . . .

Yes, "contradictory" is apt. What I was trying to get at is that "impaired" is sort of a loaded word. People might at first think of being drunk or something to that effect, but in reality impairment is a continuum from barely measurable to practically incapacitated.

 

[KevinNM]

I varied from no difference doing mechanical puzzles to taking at least twice as long for number matching puzzles. And having no idea of my NDL time or pressure at 130 feet.

 

[kwinter]

DD's claim is that reluctance to dive to depths of greater than 30m/100ft without helium indicates unusually low tolerance for narcosis and therefore represents a weakness in a diver.

I don't know where you got the idea this was a weakness. Not even from DD's initial post. The weakness would be if a diver knew she was susceptible to narcosis, but refused to use helium out of laziness, ignorance, or arrogance. I don't think you will find anyone posting that agrees with susceptibility to narcosis being a weakness in a diver.


iPhone. iTypo. iApologize.

 

[Akimbo]

Unfortunately, too few divers allow themselves the time to learn the difference between elevated CO2 and the onset symptoms of narcosis. Elevated CO2 is especially a problem among those that obsess over their RMV instead of adequate lung ventilation. The symptoms are often indistinguishable, until you overtly modify your breathing to reduce CO2.

CO2 symptoms can go away with proper breathing and can occur on Trimix or HeO2. IGN (Inert Gas Narcosis) does not, though the intensity often reduces. There’s a lot more to narcosis management than just switching mixes. It is also about learning to manage yourself under stress.

IGN is not a weakness or a strength, only a human characteristic that must be managed.

 

[Charlesl]

Unfortunately, too few divers allow themselves the time to learn the difference between elevated CO2 and the onset symptoms of narcosis. Elevated CO2 is especially a problem among those that obsess over their RMV instead of adequate lung ventilation. The symptoms are often indistinguishable, until you overtly modify your breathing to reduce CO2.

CO2 symptoms can go away with proper breathing and can occur on Trimix or HeO2. IGN (Inert Gas Narcosis) does not, though the intensity often reduces. There’s a lot more to narcosis management than just switching mixes. It is also about learning to manage yourself under stress.

IGN is not a weakness or a strength, only a human characteristic that must be managed.

I've noticed this myself. The calmer I am, and the slower I move ( Thus lower CO2 levels) the more focused and less pronounced the effects of narcosis are.

I will say that the first time I dive a location I feel the need to bring task loading to a minimum, (no camera or just a gopro mask ) and on the second and third dive at a location when the novelty has worn down and I know what I'm working with, I feel much clearer and feel more comfortable bringing my camera or branching out and exploring more places on the wreck.

Glad you brought up CO2 I don't think its talked about enough.

 

[Adobo]

I don't know where you got the idea this was a weakness. Not even from DD's initial post. The weakness would be if a diver knew she was susceptible to narcosis, but refused to use helium out of laziness, ignorance, or arrogance.

I don't claim that a "low tolerance for narcosis" to be a weakness. I am just quoting something that someone else posted. If I misinterpreted the nature of that person's post, they are welcome to correct me.

With regards to the person/event that precipitated that person's post, I will say that the diver did not refuse to use helium. She simply obeyed her usual protocol of using 32% on a dive that was not planned to go deeper than 30m/100ft.

I don't think you will find anyone posting that agrees with susceptibility to narcosis being a weakness in a diver.

... a seemingly unusually low tolerance for narcosis, which if I understood her various posts, made her very reluctant to dive more than just 100 feet without the benefit of helium in the mix.

....Many members seem to envision her as a very strong and capable diver. From my perspective, these two issues represent serious weaknesses (or at least vulnerabilities) when functioning in a high current, drift dive situation with no visual references and when drifting in water that she knew would cause her significant narcosis.

What I am getting out of DD's posts is that those who cannot tolerate diving a bit beyond 100ft without helium due to narcosis have a serious weakness/vulnerability that other divers do not have.

It's entirely possible that I am misinterpreting the spirit of those posts.

 

[dumpsterDiver]

I'd like to hear people's thoughts on this but *not* tying back to TSandM as she was not unique in her approach of when to use helium.

DD's claim is that reluctance to dive to depths of greater than 30m/100ft without helium indicates unusually low tolerance for narcosis and therefore represents a weakness in a diver.

I'd like to know people's thoughts on the use of helium to mitigate the effects of narcosis and whether or not this is a "weakness" in a diver. I'd also like to know what alternative would be suggested.

I did not claim that a reluctance to dive below 100 ft without trimix indicates a low tolerance to narcosis. As others have indicated, at least one agency (one that she was aligned with) dictates the 100 ft threshold (at least that is my understanding).

So there may be many people who adhere to this guideline, however this is not necessarily indicative of more (or less) susceptibility to narcosis.

However, even though you indicate that you don't want to point back at TSM, my comments pertain specifically to her. SHE was the one who reported a distinct susceptibility to narcosis. I don't remember the specific posts - I'm sure someone could do a search and find them.

 

[Akimbo]

… It scared the heck out of me when I found in the AOW class that I was slower doing those puzzles on the Deep dive than at the surface...

That’s not a reasonable measure. Of course you were slower. Just being underwater is a distraction and therefore impairment. It was your first “deep” dive so anxiety was understandably higher. Also, you have no idea how the compounding effect of CO2 was playing a role.

Try the same puzzle on the surface while balanced on a 2x4, wearing a dive mask, and with a few three year old girls grilling you about what you are doing. I bet your time is slower then too.

 

[RJP]

People need to find their own limits and comfort level. I am personally comfortable using air in the 200-220' range but have a lot of history to back it up.

I have no-where near your history, but my own personal experience is that I'm pretty good on air to 200fsw in warm, clear water. Here in NJ, pretty good in cold, dark, low-vis down to 150fsw or so.

I don't read divers who are overly susceptible to narcosis as being a "weakness" in any sort of pejorative sense... but it is definitely a weakness in a "matter of fact" sense. In much the same that being near-sighted is a "weakness" really. And, in the same way, it's a weakness that can be addressed. If narcosis impedes your ability to dive safely to a given depth, TMx is an option.