trimix training

[Crass3000]

I do not personally see any value on doing deep air to feel narcosis. I start recognizing it around 50ft be it cold or warm water. So diving to 100ft on Nitrox and then on trimix will give a good idea about the difference between the two. And I do not believe those who say they are not narced at 100ft

Possibly it's because I am used to drinking pretty hard and used to a good buzz???? But I have never thought I felt narced at even 130ft on air. I certainly haven't felt narced on shallower dives. I have done a bounce dive down to 182 ft in COLD water and I didn't feel narced then either. I felt as if I was in total control and very aware of my gauges and what I needed to do to make sure I didn't hit the need for decompression. I'm sure everybody would agree that at 182ft I MUST have been feeling narcosis but I had no feeling of confusion and knew what I needed to do. I guess some people must experience narcosis different? I haven't had that much experience that deep so I am open to the idea that narcosis may be quite a bit more disabling at that depth had it not been a bounce dive. For those with more experience... with more time at a particular depth does it become more disabling (let's say 10 minutes at 180ft instead of just a bounce)?

And yes I just signed up for AN/DECO and hoping for trimix soon after so I have not and will not make a habit of these deep dives. Just a little experimentation to learn a little on my own.

 

[rongoodman]

I think I saw the class the OP mentioned. There's no way I would take it.

 

[Scared Silly]

I was amazed to learn that deep air deco is much shorter for the same dive on 21/35, given the same deco gas. There is a lesson to be learned, but I don't know how valuable it is.

Frank would you give some examples? When I run 150' for 20 or 30 minutes or 180' for 20 or 30 minutes using v-planner I come out a minutes early 3-8 minutes using 21/35 rather than 21 with both 50 and 100 for deco.

 

[Dr. Lecter]

I have done a bounce dive down to 182 ft in COLD water and I didn't feel narced then either. I felt as if I was in total control and very aware of my gauges and what I needed to do to make sure I didn't hit the need for decompression. I'm sure everybody would agree that at 182ft I MUST have been feeling narcosis but I had no feeling of confusion and knew what I needed to do.

It's different for everyone, and the same person will vary from dive to dive. I'm not sure what kind of time you spent at 180', but you were surely narced. I personally expereince narcosis as a kind of sludge settling on my higher brain functions, slowing down their processing and increasing the time between input (something is wrong) and output (fixing it). How thick the sludge is depends on depth, conditions, and how I happen to be feeling that day; some days it's thin and I have very little delay in processing, other days it's heavier and the processing delay is more noticable. Some people get more narced and panicky in the dark or cold or confined spaces; I get less focused and more fuzzy-headed in the warm, clear, open water and do better with dark, cold, and/or confined when I'm deep on air. Helps keep me focused and aware.

Figuring out what narcosis does to you is best figured out gradually, because depth is unforgiving of mistakes.

 

[elan]

The biggest problem with narcosis is that people fail to recognize it...

Possibly it's because I am used to drinking pretty hard and used to a good buzz???? But I have never thought I felt narced at even 130ft on air. I certainly haven't felt narced on shallower dives. I have done a bounce dive down to 182 ft in COLD water and I didn't feel narced then either. I felt as if I was in total control and very aware of my gauges and what I needed to do to make sure I didn't hit the need for decompression. I'm sure everybody would agree that at 182ft I MUST have been feeling narcosis but I had no feeling of confusion and knew what I needed to do. I guess some people must experience narcosis different? I haven't had that much experience that deep so I am open to the idea that narcosis may be quite a bit more disabling at that depth had it not been a bounce dive. For those with more experience... with more time at a particular depth does it become more disabling (let's say 10 minutes at 180ft instead of just a bounce)?

And yes I just signed up for AN/DECO and hoping for trimix soon after so I have not and will not make a habit of these deep dives. Just a little experimentation to learn a little on my own.

 

[waterpirate]

This is all good stuff. The discussion I hoped would come, not the usual. I went to helitrox as soon as I got my personal fill station up and running and never looked back. As far as the oog and turning to air.... no thanx. On a dive to 180fsw I would also have a intermediate gas, 30/30 or similar and would get shallow and switch before rolling the dice with narcosis, or an isobaric issue. I would also recomend those looking at AN/DP look for a good instructor that will include a helitrox cert.
Eric

 

[Crass3000]

The biggest problem with narcosis is that people fail to recognize it...

I can see where that must be true.

 

[Adobo]

...Without question I will use mix below 40 metres. However I was grateful for the experience. Now at least I can say that I can do deep air dives and have reasons based on my own physiology, rather than internet dogma, as to why I do not wish to do them again.

I wonder if deep air is optional for these trimix classes. I mean, if one has already come to the conclusion that they are at their limits with nitrox at say 40m/133ft, is there any point in doing the deep air dive as part of the class? Or mandating extended range/deep air training prior to taking trimix training?

---------- Post added July 19th, 2013 at 06:37 PM ----------

Other than what I just said above, there are dives where you and your buddy may not plan on going deep and therefore both take air, but for some reason one of you is forced lower than intended (downcurrent, sudden wing failure, health issue, wrong/bad gas, take your pick). Are you going to sit at 130' and wave/wait, or go down and help?

Got any examples that aren't contrived, far fetched or otherwise ridiculous?

 

[Dr. Lecter]

Got any examples that aren't ridiculous, far fetched or contrived?

Trust me, convincing you of the potential value of at least some experience with a relatively high END before you toddle off to learn to dive helium only and forever, is not high on my list of things to do today.

If you'd like to claim that the scenarios I described have never happened, you would be dead wrong. If you'd like to claim it would never happen to you, feel whatever you like -- I couldn't care less how well or how poorly you prepare yourself for your dives.

 

[Adobo]

Trust me, convincing you of the potential value of at least some experience with a relatively high END before you toddle off to learn to dive helium only and forever, is not high on my list of things to do today.

If you'd like to claim that the scenarios I described have never happened, you would be dead wrong. If you'd like to claim it would never happen to you, feel whatever you like -- I couldn't care less how well or how poorly you prepare yourself for your dives.

Well I already have trimix training so too late for that I guess.

But so there are no hard feelings, let me offer you a cookie: