My buddy claims he was not narced at 135' (45m)....

[Matt83]

i havent ever felt a strong narcosis, or any narcosis for that matter. Im not sure if I dont get narced or if i just dont notice, because Im narced. Ive dove to 130ft a few times and havent ever done anything stupid or felt stupid. Different people just respond differently.

 

[jagfish]

To the OP...
Looks like you've got some great information/expereince in this thread, mixed with some loopiness. Hopefully, you are able to sort between the two. This exercise alone will speak volumes...

You made a very smart move evaluating your ability to complete your dive "objective" and making the call to thumb the dive.

I agree with others' observation that narcosis is a biological fact, like blood alcohol content (BAC). The amount of disorientation that we experience or perceive varies for many reasons, as does our reaction to the amount of BAC varies among individuals.

Some observations I've not seen come up:

- It takes some divers time to get past the "gross" sensations of scuba (the gear, the environment, the good and bad stress) to be able to feel the finer degrees of experience; narcosis and temperature. I find the more experienced and relaxed a diver becomes, the more colors of narc they will be able to perceive (and the easier they feel the cold). My personal tell-tale signs are warm, buzzing lips and my bubbles start to sound like bells.

- Cold temps and poor visibility can contribute to narc. What a diver can do/accomplish in terms of task complexity deep on air in Tropical temps/unlimited viz cannot be accomplished in "lesser" conditions (my experience).

What to do?
Coming full circle, you already highlighted what I see as the most important point. Accepting that narcosis to some degree is a fact of diving life (to be mitigated by depth and gas choice when possible), I make decisions before and during the dive about the tasks I am willing to undertake.

If my anticipated/experienced impairment in a given task would jeopardize individual or team safety, the plan would have to be scrapped or modified.

In this, you made the right decision...

 

[Green_Streak]

I can only say my experience, and granted that's not much, made my first 2 dives to 100' or so today using air(always used nitrox before when going to this depth). I can say this much, somewhere around 85-90 feet, I noticed it. Did notice myself taking more time than usual thinking over what I was doing before doing it. I was down in a cool lil cavern(Paradise Springs in florida) and had decided before we went down that we'd poke our heads back into the cave portion(5-10 feet at the most). I can easily see though if I hadn't noticed it, it could have turned into something dangerous.

 

[SDAnderson]

I can only say my experience, and granted that's not much, made my first 2 dives to 100' or so today using air(always used nitrox before when going to this depth). I can say this much, somewhere around 85-90 feet, I noticed it. Did notice myself taking more time than usual thinking over what I was doing before doing it. I was down in a cool lil cavern(Paradise Springs in florida) and had decided before we went down that we'd poke our heads back into the cave portion(5-10 feet at the most). I can easily see though if I hadn't noticed it, it could have turned into something dangerous.

Except most experienced divers will tell you that oxygen is roughly equivalent to nitrogen when it comes to narcotic effects. Nitrox won't keep you from getting stoned, that's why divers use trimix: they're replacing both nitrogen and oxygen with helium so that they don't get loopy.

 

[boulderjohn]

Except most experienced divers will tell you that oxygen is roughly equivalent to nitrogen when it comes to narcotic effects. Nitrox won't keep you from getting stoned, that's why divers use trimix: they're replacing both nitrogen and oxygen with helium so that they don't get loopy.

I had always heard that, too. A recent thread on this topic raised a lot of doubts. The problem is that it cannot be tested. Nitrogen narcosis is tested by raising the PPN2 to very high levels and checking the results. Raising PPO2 to such levels is too dangerous because of toxicity. The other problem is that we don't know for sure the degree to which the body's use of O2 impacts the effects. What I got from the thread is that we really don't know. There is reason to believe Nitrox is more narcotic. There is reason to believe that it is about the same, which is a popular belief. There is also reason to believe it is less narcotic. I now officially don't know one way or another.

 

[dragon_chaser]

I can only say my experience, and granted that's not much, made my first 2 dives to 100' or so today using air(always used nitrox before when going to this depth). I can say this much, somewhere around 85-90 feet, I noticed it. Did notice myself taking more time than usual thinking over what I was doing before doing it. I was down in a cool lil cavern(Paradise Springs in florida) and had decided before we went down that we'd poke our heads back into the cave portion(5-10 feet at the most). I can easily see though if I hadn't noticed it, it could have turned into something dangerous.

PLEASE! So what mix are you using for your 100 foot dives? Running what PO2? How long have you been EANX certified? Sounds like a stat to me!

 

[shinybadgesofcourage]

I can only say my experience, and granted that's not much, made my first 2 dives to 100' or so today using air(always used nitrox before when going to this depth). I can say this much, somewhere around 85-90 feet, I noticed it. Did notice myself taking more time than usual thinking over what I was doing before doing it. I was down in a cool lil cavern(Paradise Springs in florida) and had decided before we went down that we'd poke our heads back into the cave portion(5-10 feet at the most). I can easily see though if I hadn't noticed it, it could have turned into something dangerous.

I think you misread your google results, EANx does not increase in awesome points as you go deeper. Do you go hardcore and play who can touch the tombstone without taking a tox hit with your dive buddies?

 

[RickI]

Narcosis, it depends, not only within a given diver but even more so among a group of divers. There are so many variables. You can habituate some of the effects through experience, some of the time but not always. The onset is reported later by some divers than others, perception or fact, who knows? In extremes I've found signs can blend with O2 toxicity symptoms. Not a good place to be.

What is the earliest sign of narcosis that diver's perceive? In my case it is in hearing. The regulator exhaust sounds higher pitched, more "silvery." That is usually followed by a "lightness" at the top of my head. The symptoms expand there after.

 

[refinished]

For me it starts with the hearing as well. I understand what you mean by 'silvery' even though its an odd word for sound attenuation. I grow more conservative when the world starts to sound that way. Or at least I try to....

I know my usual narc range by the amount I am able to remember a couple days post dive. My buddy and I often chatter in detail about what a great dive we just had as soon as we climb up on the boat. I find that a couple days later, I can remember the conversation about certain parts of the dive much better than the actual events from which the chatter sprang. It's as though the process that makes short term memory into long is affected. I make the assumption that there is a correlation to judgment impairment. A history of this tells me that I have the potential to be impaired when the END is even as shallow as 100ft. A bit of helium has made a marked improvement for me.

I've forgotten large portions of dives as shallow as 115ft. Others at the same depth, I recall as clear as a bell. 160 is the deepest I've been on air and I won't do it again if there is helium on hand.

 

[Terry2Puds]

You wil know you were narked when you do a few dives on trimix.

I have recently passed my Normoxic Trimix course. Having dove the same location as training divers to 50m on air, we then did the same dive on a mix of 23/30. Everyone who I know who dives on trimix told us you see a big difference to an air dive. Well at 50m it made a massive difference to all of us on the course. Everything was much more clear. You may not think you get narked as I did, boy was I wrong.

Any future dives past 40m will be on trimix for me.

When you look at rebreather training they only allow you to 40m on Mod 1. Past 40m you need trimix. This is to ensure that you have a clear head to monitor your handsets and deal with any difficulties that arise.

Safe diving.