Question Ever experienced Nitrogen Narcosis?

[boulderjohn]

I went down to 100' during my AOW and did math with my instructor, we also looked at colour change. She was pissed when we all came up, that nobody in the class got narc'd.

PADI removed the problem-solving exercise from the AOW deep dive (maximum depth = 100 feet), presumably because of this. With so few people exhibiting signs of narcosis, it was having the opposite of the desired effect by indicating that narcosis was nothing to worry about.

 

[tursiops]

it actually took a couple of good shots on inflator, to start the elevator going.

Bad practice! It is not an elevator button! If you were neutral at depth (it sounds like you were not) then one kick upwards is all it takes to initiate Boyle's Law.

 

[Gandalf-the-Diver]

one kick upwards is all it takes to initiate Boyle's Law

Elevator I guess was a bad choice of words, as the one kick upwards I tried 1st, expectiing Boyles Law to kick in. I tried a couple of kicks, didn't work. Shot in BCD inflator, things seemed to be working better, and was able to begin a controlled ascent.

 

[boulderjohn]

I went down to 100' during my AOW and did math with my instructor, we also looked at colour change. She was pissed when we all came up, that nobody in the class got narc'd. I have been below 100' a number of times now; a couple of weeks ago, I bounced down to 135' and last night, dropped down to 120' to check out a huge GPO. I am pretty aware of how my body is reacting, and I have not felt like I am getting narc'd. My buddy on last nights dive, mentioned she felt something funny around 95', but not for long.
I have been below 110', close to a doz times now, with about half of that, below 120'. The one thing I really noticed, when I went to 135', at 125' I started putting little puffs of air in my dry suit to start slowing my decent down. It actually took a few good hits on my BCD inflator to slow and stop my descent. Knowing I had to come up right away, it actually took a couple of good shots on inflator, to start the elevator going. I found this interesting, as at shallower depths, I use my breath control for slight increases and decreases in depth; didn't work as well at 135'. I regularily dive to 100', and I am diving 2-4 times a week. As for getting narc'd, I still do not feel like I have been narc'd, or at least my body does not seem to react to depth, yet.

One of the characteristics of narcosis for most people is they have no sense that they are experiencing it. I am one such person. I have never felt any different in situations where narcosis would be expected, but I have had clear and unmistakable evidence of narcosis on several occasions when I felt perfectly fine. In those situations, something has to happen requiring action on your part, action that is clearly subpar. If nothing like that happens, you can be narced and never know it.

Having to lay on the inflator hose to get neutral while deep has nothing to do with narcosis. It is a natural consequence of Boyle's Law. At 135 feet the air in your BCD is compressed 5 times what it would be at the surface, so you have to add that much more air to become neutral at that depth.

 

[Gandalf-the-Diver]

PADI removed the problem-solving exercise from the AOW deep dive (maximum depth = 100 feet), presumably because of this. With so few people exhibiting signs of narcosis, it was having the opposite of the desired effect by indicating that narcosis was nothing to worry about.

My instructor for the class, actually spoke about NN and the dangers of it, quite a bit. Stressing how this was not a good thing.

 

[boulderjohn]

Elevator I guess was a bad choice of words, as the one kick upwards I tried 1st, expectiing Boyles Law to kick in. I tried a couple of kicks, didn't work. Shot in BCD inflator, things seemed to be working better, and was able to begin a controlled ascent.

You still had not added enough air to the BCD to become neutral, so you needed to add the air to be neutral and then begin the ascent.

 

[Gandalf-the-Diver]

If nothing like that happens, you can be narced and never know it.

Very true.

Having to lay on the inflator hose to get neutral while deep has nothing to do with narcosis. It is a natural consequence of Boyle's Law. At 135 feet the air in your BCD is compressed 5 times what it would be at the surface, so you have to add that much more air to become neutral at that depth.

Which I thought about while I was doing it. Thought to myself, I am way deeper than normal, air is compressed more than usual, that is why this is happening. As a side note, I finished my dive with 1100 psi in my HP100 Faber.

 

[Gandalf-the-Diver]

You still had not added enough air to the BCD to become neutral, so you needed to add the air to be neutral and then begin the ascent.

I was figuring that out as I was slowing my descent down, the amount of air required for the task, was greater than expected.

 

[boulderjohn]

I was figuring that out as I was slowing my descent down, the amount of air required for the task, was greater than expected.

That's why a lot of inexperienced deep divers finish their descents with a full on crash into the bottom.

 

[Gandalf-the-Diver]

That's why a lot of inexperienced deep divers finish their descents with a full on crash into the bottom.

When a cpl of puffs in my dry suit had no effect on descent, that is when is dawned on me, I needed more. The bottom, was still another 75' to a shelf, before it goes deeper.