Narc?

[Kim]

I agree that narcosis can come on at any depth. My point was that I would consider it unusual at 26 m and if I was a new diver and it happened (as I believe the question was about) I would definately investigate further. If you are susceptable to narcosis at that depth I believe you need to know that. I also totally agree with the fact that it depends a lot on your physical/mental condition at the time of the dive, something that can vary considerably from day to day.

 

[DennisW]

I am still amazed that people say "Nitrogen Narcosis can come on at any depth." That is just the wrong statement. All divers, whether they believe it or not, are affected by Nitrogen Narcosis. I usually don't feel impaired either, that does not mean I'm not impaired. Some people are better able to handle the impairment, that doesn't mean they aren't impaired. I usually am aware of nitrogen narcosis on deeper night dives. Probably because I am more anxious about night dives.

Do a little experiment the next time you dive below about 60 ft. On the surface, make up a couple of simple math problems, multiplication of two 3 digit numbers would be good. Do the multiplications on the surface and time yourself. Then put them on your slate and then multiply them at depth and time yourself. Look at the difference. You may be surprised, then again, you may not.

 

[mikelegurra]

Do a little experiment the next time you dive below about 60 ft. On the surface, make up a couple of simple math problems, multiplication of two 3 digit numbers would be good. Do the multiplications on the surface and time yourself. Then put them on your slate and then multiply them at depth and time yourself. Look at the difference. You may be surprised, then again, you may not.

when i was doing the OW there was a girl taking the Advanced. the instructor had a slate he had numbers up to 16 or 20 on a 4x4 (or 4x5) table. as far as i could tell they used it for the deep dive and she had to point to the numbers, which were mixed, and she was timed during the dive and after the dive, on the boat.

is this a skill you have to do on AOW ? is it to test the narcosis effect or is there any other point in this exercise ?

 

[stefo2]

when i was doing the OW there was a girl taking the Advanced. the instructor had a slate he had numbers up to 16 or 20 on a 4x4 (or 4x5) table. as far as i could tell they used it for the deep dive and she had to point to the numbers, which were mixed, and she was timed during the dive and after the dive, on the boat.

is this a skill you have to do on AOW ? is it to test the narcosis effect or is there any other point in this exercise ?

Yes, that's right. Either this one or something similar, even though I'm not sure you actually have to do it, I never did on my AOW, but that was a few year ago.
I did actually do this test a few months ago just for fun, when I was doing a dive together with two AOW students, and I did A LOT better at 30 metres than at the surface! Seriously. I think it had to do with the fact that I did remarkably badly on the surface, was probably not quite awake yet, but still, at 30 metres I not only was a lot faster than at the surface, but also a lot faster than the other two. Which goes to show that everyone is affected differently by narcosis.

 

[H2Andy]

Errr....i don't quite now where to post this to. I have a question. I know it depends on individual body to have nitrogen narcosis, but doing deep dive, 30m (PADI Advance OW) is there possibility to act foolish. My buddy last week trying to give her regulator to the fish! And we only dove 26m. Is it normal? :frown2:

i am not sure if this is a real scenario you are asking about
or a hypothetical (it gets used a lot), but 78 feet is
rather shallow to experience the severe behavioural
impairement your friend exhibited.

that said, some people might be much more succeptible to nitrogen narcosis than others, they might be on medications that might make them more succeptible. also, the speed of
the descent has been known to be a factor on how bad a hit you take.

 

[Lightning Fish]

When I went through the AOW we were taught that on deep dives it is possible for divers to become super focused on whatever task they are doing, due to narcosis. Super focused to the extent that other tasks become ignored, such as monitoring your depth or air pressure. If a diver is affected in this manner they and their buddy need to be aware of it.

The task we had to do was open a combination lock. It took my buddy 15 seconds to open the lock on the surface and 4 seconds at 75 feet. That was in poor viz and with 5 mm gloves on.

Cheers,
Bill.

 

[S C]

Nitrogen give narcotic effects when under pressure. But what we are interested is at what stage it impairs the diver’s ability to think clearly, which is a contaributing factor for a diver to make a wrong decision, might resulted diver not able to exit water safely.

I am still amazed that people say "Nitrogen Narcosis can come on at any depth." That is just the wrong statement.

So the statement is understood as that the narcotic effect can take place any any depth which able to impairs a diver's ability to perforamce as normal.

Below info is by US Navy dive manual

100 ft - Intoxicating effect similar to that of alcohol. Slowing of mental activity.
150 ft - Slowing of reaction time and reflexes. General euphoria. ixation of ideas.
200 ft - Difficulty in concentrating or reasoning. Difficulty in remembering what to do or what has already been done.
240 ft - Observations often inaccurate. Likely to make incorrect decision about what to do. Diver may not care about job or safety

For your info, we had put some guys to answer maths question in a chamber at 132 ft. They took longer time to finish the paper than on surface.

 

[Diver0001]

When I went through the AOW we were taught that on deep dives it is possible for divers to become super focused on whatever task they are doing, due to narcosis. Super focused to the extent that other tasks become ignored, such as monitoring your depth or air pressure. If a diver is affected in this manner they and their buddy need to be aware of it.

The task we had to do was open a combination lock. It took my buddy 15 seconds to open the lock on the surface and 4 seconds at 75 feet. That was in poor viz and with 5 mm gloves on.

Cheers,
Bill.

Hi Bill,

75ft isn't really a good comparison. If he were made to do it in 130 or 140ft of water then you would really notice a performance hit.

As for tunnel-vision (over focusing). I've heard of it but I've never experienced it. My experience is that I get more and more air-headed the deeper I go. I notice a lack of concentration, not an overabundance.

R..

 

[Michael Schlink]

I'm with Dennis W once you start hitting close to 4atm NN is going to start showing up so 27m, which is close to 90ft is close enough.
As far as the "timed skill" on the PADI AOW, it is a required skill and is designed to demonstrate to the student that impairment can and does occur without the diver being aware of it. A puzzle, tie a rope, untie a rope, etc. etc.
As far as being afraid of NN, no need, just proper respect and understanding how to handle the situation for yourself and your buddy. Usually ascending to a shallower depth and continuing your dive will suffice.
As has been mentioned some of you may want to go back to your books or get with an instructor as to recognize and deal with NN-Dive safe-M

 

[Burner]

My girlfriend had this happen to her at around 100ft when she was paired up with a random buddy on a dive boat.