Tri-Mix Agencies?

[waterpirate]

" trimix is useless as a shallow diving gas "
" narcosis does not present untill the outer limits of recreational depths "

These are pretty broad wide sweeping statements that some of us would feel make you as far right as some are far left?

Trimix for dummies at 150fsw is agreed a bad idea, but a lot of skilled divers think that 21% is what you put in your kids bicycle tire. " a squirt of helium " as you call it has a very broad appeal to people who are succeptable to narcosis, and people who dive challenging conditions and or task loaded heavily at rereational depths. Thus the recreational trimix and triox classes being introduced by some agencys. Anyone who shows up for that class is going to be evaluated by instructor and told add nauseam that it is helium with a speed limit, content and depth.
It is just a tool.
Nothing magical or scarry about it
Eric

 

[DevonDiver]

Hi Eric..

Read my comments in context. I was balancing the cost of training, equipment and gas...against the benefits of trimix within recreational ranges....and within no-decompression limits.

If a recreational diver had a severe reaction to narcosis and If they had ample funds, then they could opt for a normoxic trimix gas.

Above 30m (shallow) it is pointless. I never met anyone who suffered from narcosis at that range...and even then, it would probably stem from pre-existing anxiety or poor breathing. Those avenues should be addressed before the 'quick fix' of putting helium in your tank.

Within the 30-40m recreational range, the use of normoxic trimix can benefit a small minority of people who are susceptible to narcosis. But given the short NDLs at those depth, coupled with the high cost of helium... it seems a very cost ineffective solution. I know what GUE recommend...and I don't disagree with the principle.... but, it isn't the only way to address the problem. For overhead environments, where a clear head is essential... then it makes some more sense. For normal open water diving, it is an unnecessary expense IMHO.

 

[ScubaFeenD]

If a recreational diver had a severe reaction to narcosis and If they had ample funds, then they could opt for a normoxic trimix gas.

Wouldnt triox be enough to bring them to recreational limits within MDLs?

 

[Rainer]

What exactly do you take "triox" to mean?

Wouldnt triox be enough to bring them to recreational limits within MDLs?

 

[ScubaFeenD]

What exactly do you take "triox" to mean?

>21% O2 +helium. From what i understand there is a very distinct difference between trimix and triox, even though recreational trimix is usually triox.

 

[Rainer]

The *only* thing distinct about "triox" is GUE's usage of the term. No one I know refers to hyperoxic trimix as triox (including GUE trained divers). It's a dumb term. There's nothing "tri" about the "ox".

I have a handful of dives on 30/30 and several more on 25/25. The latter is occasionally useful to me. The former not so much. I can't imagine using either for an NDL dive. If you're going to drop the cash for the gas, might as well stick around for >10 minutes to enjoy the show. IMO, of course.

>21% O2 +helium. From what i understand there is a very distinct difference between trimix and triox, even though recreational trimix is usually triox.

 

[waterpirate]

I stand by my opinion based on the following.
Heavy task loading and dive conditions well within a ndl rec dive make helium a logical choice.
Cold, low vis, 22#+ dinner is around behind you, shooting line is in your isolation manifold and dinner just pulled you head first into a hard, sharp, piece of rusty crap.

It is very easy to control breathing, anxiety, narcosis in warm clear tropical waters when you are just swimming around "looking at stuff".
Eric

 

[DevonDiver]

Hi Eric...

I don't agree. Any diver can obtain a comfort level within a given water condition. Likewise, any diver inexperienced in those conditions will suffer an increase in stress. A predominantly tropical diver who moves to temperate waters will have to acclimatize. Just the same for a novice diver in those conditions. Does that make hyperoxic trimix (TriOx) a 'crutch' for a lack of comfort in the water? Isn't that counter-intiuative to suggest that highly stressed divers should opt for more complex gas mixes?

Hi ScubaFeenD...

The concept of 'TriOx' (if you want to call it that) brings a plethora of pros and cons. Just as with nitrox, it introduces a MoD to the dive. It's a very expensive and complicated solution to a problem that few divers ever face.

As I said earlier.... the 'text book' solution for narcosis is to ascend. Most divers can manage that easily. If you feel the effects of narcosis, move upwards in the water column to solve the problem. If that isn't an option (overhead environment), then TriOx may be a solution.

The majority of people who suffer from narcois incidents have progressed to a deep depth without a progressive increase in depth in previous dives. Breathing rate accounts for many narcosis hits also. Pre-existing stress is another. Those can all be avoided without the need for $$$'s spent on gas mixes and training...

However, given the price of helium, this would rarely be a financially justifiable solution for the vast majority of recreational divers. Oxygen is cheap... so it is becoming a popular tool in the recreational market. Helium blends aren't likely to ever be feature in that market.

Now.... if you just happened to be in a situation where money was not a concern... then TriOx would be a defininate option. Of course, you'd still have to find a rich and extravagent buddy to dive with.....

For me... I'd rather spend my scuba budget on other things, rather than expensive gas to solve a non-problem for recreational diving....

I am certainly not adopting an 'old guard' mentality in resistance to TriOx. It is a tool.... but not one that has many benefits for many divers. It certainly wouldn't be something I recommended as a training course for a recreational diver.... and it certainly isn't what the OP was suggesting he would do.

 

[MXGratefulDiver]

I stand by my opinion based on the following.
Heavy task loading and dive conditions well within a ndl rec dive make helium a logical choice.
Cold, low vis, 22#+ dinner is around behind you, shooting line is in your isolation manifold and dinner just pulled you head first into a hard, sharp, piece of rusty crap.

It is very easy to control breathing, anxiety, narcosis in warm clear tropical waters when you are just swimming around "looking at stuff".
Eric

All well and good ... but what do you say to the diver who isn't yet well-adapted to the notion of solving problems underwater ... and who experiences some condition that produces an overwhelming urge to get to the surface ASAP.

I had a diver do that on me yesterday, about 40 minutes into a pretty aggressive dive when we got hit with an unexpected downwelling. As I was grabbing onto a rock to wait out a rather powerful surge of water that wanted to send us further and deeper into the Tacoma Narrows than I wanted to go, he suddenly let go and headed for the surface. I ended up pulling myself upslope until the downwelling passed ... at which point we reconnected on the surface, where he told me he just HAD to go up.

Had that diver been on a helium mix, he'd almost certainly have spent the day in the chamber ... if he didn't end up giving himself an AGE on the way to the surface.

Helium comes out of solution way faster than nitrogen ... so before someone decides to start using it, they'd damn well better have trained themselves to solve their problems underwater ... even if it is "just a recreational dive" ...

... Bob (Grateful Diver)

 

[Blackwood]

>21% O2 +helium. From what i understand there is a very distinct difference between trimix and triox, even though recreational trimix is usually triox.

I agree with Rainer's reply. Triox, Helitrox, Heliair and so on are agency-specific terms.

In my lexicon, if it's made up primarily of O2, He and N2, it's trimix.