Deep Air Dives In Tech Classes

[mainedvr]

Over heard some discussion among some tech students about some of their deeper dives being on air and being narc'ed. Is there are purpose to doing such dives? Do most tech classes have this as a component? I know a few agency's do not but was just wondering why add a possible issue to a tech class. Not really asking if you agree or disagree just looking for some explanation if there is any.

Thanks,

 

[JohnnyC]

I took TDI Extended Range, which is basically deep air. All it really did was confirm to me that I don’t like diving deep without helium.

There are some places where helium is unavailable or cost prohibitive. Most AN/DP courses do not require helium so for a lot of people it’s not even on their radar unless the instructor makes the student aware that it’s an option.

 

[lv2dive]

When I took PADI's Tec50 class, I had the choice to do the last two experience dives on Trimix or a "best mix" EANx mix. I figured since I would be certified to do theses dives on deep air, better to do them in class with an instructor, rather than on my own.

I was very narc'ed in the low vis, cold (40's F) lake water, and going forward, pretty much decided to follow some other agencies' recommendations regarding Helium for dives deeper than 100'.

 

[Bob DBF]

Back when I was doing those dives there was no alternative. Now, as @JohnnyC relates, helium may be unavailable or cost prohibitive. In these cases it is better to have an understanding and experience with narcosis so, if nothing else, you can remove yourself from the situation before it gets out of hand.


Bob

 

[tomfcrist]

I guess it depends on your definition of deep air. Most likely these folks are talking about their experience with the TDI ext range course (180’ max?). 180 is very manageable from a narcosis standpoint in blue water that’s nice and warm...I have never seen it taught in cold dark water...where it is much less tolerable.

I don’t blink at a 170’ air dive off Hatteras or KL. That’s not “deep air” to me. Now off NJ...I don’t want to dive air at that depth. I think it’s a personal limitation that takes some sort of real world experience to appreciate...thus I think that particular course is beneficial in that it shows you (or at least has the ability to) how narcosis can truely be a ****** experience.
I find it would be even more helpful to do 2 dives in that range..one on air and one on mix...in the same conditions to give the student a reality check of how clear headed they are on mix vice air.

 

[mainedvr]

Back when I was doing those dives there was no alternative. Now, as @JohnnyC relates, helium may be unavailable or cost prohibitive. In these cases it is better to have an understanding and experience with narcosis so, if nothing else, you can remove yourself from the situation before it gets out of hand.


Bob

Figured that would be one reasoning to get the feeling so you know when its about to happen, not trying to go a different direction but wonder if doing more deep dives on air and getting narc builds a tolerance or just the ability to handle it if need be.....Thanks for the response.

 

[mainedvr]

I find it would be even more helpful to do 2 dives in that range..one on air and one on mix...in the same conditions to give the student a reality check of how clear headed they are on mix vice air.

Yeah that seems like a good idea like Bob said get an idea of what it feels like so you can handle your situation and or get out of that depth if need be.

 

[mainedvr]

When I took PADI's Tec50 class, I had the choice to do the last two experience dives on Trimix or a "best mix" EANx mix. I figured since I would be certified to do theses dives on deep air, better to do them in class with an instructor, rather than on my own.

I was very narc'ed in the low vis, cold (40's F) lake water, and going forward, pretty much decided to follow some other agencies' recommendations regarding Helium for dives deeper than 100'.

So the dives up to that point it was mandatory to do on air?

 

[northernone]

I can't speak for any agency but narcosis management is best learned under direct supervision.

Since it's a common risk which I've suspected I've encountered as shallow as 40ft I'm glad in different conditions I've been exposed to how to respond with an experienced mentor. I don't believe adding helium is the inoculation as there are other significant factors involved which might result in a diver narced. When that situation comes, I'd be glad my instructor taught me a few things practical about it.

Defining "deep" rather nebulous as well. Just drying out from a dive to 250' which might be deep to some or the first deco stop for others.

Dive and let dive,
Cameron

 

[Bob DBF]

Figured that would be one reasoning to get the feeling so you know when its about to happen, not trying to go a different direction but wonder if doing more deep dives on air and getting narc builds a tolerance or just the ability to handle it if need be.....Thanks for the response.

It happens on a sliding scale depending on conditions in the water and yourself, it's happening as you go deeper and it becomes your number one job to know how you are impaired. As far as have determined I do not build up a tolerance, but can manage narcosis better if I work up to deep dives slowly.


Bob