UW narcosis monitoring...do you use it?

[MASS-Diver]

When I first started diving I was tauhgt "the old narcosis check": you flash any number of fingers at your buddy and he (as fast as he can) shows you the same number of fingers plus 1.

Alot of divers don't use this method or haven't heard of it. Do you find it usefull? It doesn't work well with mits and everyone likes to give you one finger back (the middle one), but, even when diving with NITROX (or for more advanced divers TRIMIX with a realitively shallow EAD), I think it's important to keep track of how impaired you and your buddy may be. I don't feel it's ok to say, "well were diving with Nitrox at 90' so there's no need to even think about narcosis.

I have a few shipwrecks that I dive over and over, somtimes I feel narced, sometimes I don't. I don't think this is just me noticing it sometimes either, because in observing my buddy sometimes he seems a little off and sometimes he looks fine (when you dive with someone alot, it's easy to pick up on even small changes associated with narcosis).

So, that's what worries me about narcosis, in my limited experience, I can't predict it. For example, if I go out tonight and have 4 beers there's not much chance I'm going to wake up the next morning half naked on my lawn. I have a pretty good idea how 4 beers will affect me. With narcosis I've had a lot of trouble pinning down why sometimes (on the same wreck,at the same depth) I feel fine while other times I'm imparied. Narcosis seems very complicated to me.

So, back to the original question, what do you think of the finger test and do you have any other ones (besides ripping off your buddy's mask at 100' and observing his reaction)?

 

[Amanda]

I never heard of that trick but it looks like a VERY good one. I'll definitely use it. you never really know when your buddy gets narced, do you ? So this seems like a good way to figure out.

Thanks !

 

[Nessie]

Hi,
the problem with this method is that if you use it regularly it becomes automatic and you can easily perform the test even when you are quite narced. The test is a bit more reliable when you use another method every dive, like one time add one finger, next time minus one, another time plus two and so on, so that you really have to think everytime.
It is not workig for me as I dive the whole year with three-finger-gloves which gives you not really many options to signal numbers.

 

[knotical]

The techniques mentioned above are great because they require no special equipment.

Nessie’s suggestions are better because they include memory and subtraction, reducing automatic responses. I was taught another variation that’s slightly more rigorous because you have to remember two things. Before the dive, buddies agree on both a starting number and how it will be used.

A common one for beginners:
“Subtract whatever I signal from the starting number.”
At depth, one diver signals a number (preferably less than the starting number ) and the buddy responds with the difference between what was agreed on and what is signaled.

Example: We agreed on the number 4. If you signal 3, I should respond 1.
If I then signal 4 you should respond zero. (Our two signals should add up to 4.)

Short practice before submerging is good, to be sure both buddies understand. It’s a shame for my buddy to think I’m narked, but it’s really just poor math skills. And why was I was still narked at the safety stop? :11:

You can come up with a lot of variations. Just don’t make them so complex that the dive’s no longer fun.

We often use low numbers to simplify one-hand signals, but higher numbers are easy one-handed, if you use cave divers’ signals (vertical fingers for 1-5 and horizontal for 6-9).

Wish I had an answer for three finger gloves or mittens, but then I seldom do both deep and cold.

 

[miketsp]

Yes - on dives below 30m.

 

[wedivebc]

A real test would be to give the reponse in binary so with 5 fingers you could have 32 options.

 

[simbrooks]

A real test would be to give the reponse in binary so with 5 fingers you could have 32 options.

Couldnt even do that on the surface with hours on my hands (fingers), but then again only computer geeks work in binary it seems

We did this for the deep test, but we all know there is a certain amount of narc going on at depths beyond 90ft or so. I have found my worst narcs are when i am working hard in current "deep" in caves, but then again i also have awareness when drinking as to the effects of what it is doing to me, and i am by no means a lightweight, just trying to stay aware.

 

[matt_unique]

When I first started diving I was tauhgt "the old narcosis check": you flash any number of fingers at your buddy and he (as fast as he can) shows you the same number of fingers plus 1.

Alot of divers don't use this method or haven't heard of it. Do you find it usefull? It doesn't work well with mits and everyone likes to give you one finger back (the middle one), but, even when diving with NITROX (or for more advanced divers TRIMIX with a realitively shallow EAD), I think it's important to keep track of how impaired you and your buddy may be. I don't feel it's ok to say, "well were diving with Nitrox at 90' so there's no need to even think about narcosis.

I have a few shipwrecks that I dive over and over, somtimes I feel narced, sometimes I don't. I don't think this is just me noticing it sometimes either, because in observing my buddy sometimes he seems a little off and sometimes he looks fine (when you dive with someone alot, it's easy to pick up on even small changes associated with narcosis).

So, that's what worries me about narcosis, in my limited experience, I can't predict it. For example, if I go out tonight and have 4 beers there's not much chance I'm going to wake up the next morning half naked on my lawn. I have a pretty good idea how 4 beers will affect me. With narcosis I've had a lot of trouble pinning down why sometimes (on the same wreck,at the same depth) I feel fine while other times I'm imparied. Narcosis seems very complicated to me.

So, back to the original question, what do you think of the finger test and do you have any other ones (besides ripping off your buddy's mask at 100' and observing his reaction)?

I have never used this test. Ha ha ha - I can imagine half of my buddies would reply with one special finger as well. I just oberve my buddy for unusual reactions or movements. The speed at which they reply to regular hand signals is also an indicator. I was once diving with a buddy who became narced at 120'. He was totally calm and in good form. I gave him the OK signal and he just stared back at me. I gave the same signal again and there was no response. I was 2' from him face to face when I gave the signals. When we surfaced of course the first thing he said was "I was so narced down there".

If a buddy ripped my mask off under any circumstances they would experience 'extreme duress' once I resolved the problem.

--Matt

 

[bubblelogist]

Interesting... I remember a dive at about 90 ' and my buddy touching the wheel but didn't remember once back on surface . I will definatly add it to our safety drills. Usually we look at each other's eyes, and at each others reaction. We know ourselves very good and I can say when my buddy is narked, and he can tell when I am.

 

[simbrooks]

I have never used this test. Ha ha ha - I can imagine half of my buddies would reply with one special finger as well. I just oberve my buddy for unusual reactions or movements. The speed at which they reply to regular hand signals is also an indicator. I was once diving with a buddy who became narced at 120'. He was totally calm and in good form. I gave him the OK signal and he just stared back at me. I gave the same signal again and there was no response. I was 2' from him face to face when I gave the signals. When we surfaced of course the first thing he said was "I was so narced down there".

But at least he realised it, lots of divers i hear about just state they werent narc'd and they were so obviously badly affected.