Why Recreational Triox ??

[MikeFerrara]

I don't know if the class requires redundancy or not.

I'm also not so sure that having a lttle helium in the tank increses the risk of either DCS or AGE. Either way I wouldn't say they're ignoring it. In fact, given the ascent procedures and dive planning strategies that GUE teaches I think the mix will work just fine.

Given the number of people who I've already heard about that didn't pass the course on the first try I wouldn't say it's a card selling class. It sounds to me like they mostly just split off part of tech 1. If any agency is teaching real problem avoidance and underwater problem solving, I think it's GUE so I really don't think we're going to see graduates getting hurt doing ESA's.

Which leads us to the "why not" I think the name of the class leads people to believe the point of the class is the gas. I think the point of the class is teaching the planning and skills to dive to 120 ft and the gas is just one of the tools they provide.

Fill express...
I think $0.3 per cu ft for 30/30 stinks. When I had a shop I charged $0.5 per cu ft (it cost me $0.3) for helium and my fill would still have been WAY cheaper. Especially if they're blending by continuous flow and able to use all their helium this is one MONSTER markup.

 

[chrisch]

I am booked in on the IANTD Advanced Rec Trimix for later this year subject to work...

The gas is not that expensive compared to EAN (I'm UK based and a qualified blender) so not an issue.

For me its the dives between 35m and 45m that are the target. Less than 35 (110 fsw I think) then Nitrox is fine. Over 45m (150fsw) then you need doubles and normoxic and my wife is not ready to do that yet..

This means it will be about 5-10% of my diving at most and the rest of the time I will be on EAN32.

Using V Planner you get longer with 25/25 than EAN25 and a quicker deco with EAN50. The course (combined with IANTD Deep Diver) teaches DSMB deployment and deep rescue skills that are worthwhile and not available to me in the PADI environement. Furthermore the course introduces gas-switch (to EAN50) which also gives deco skills not available in PADI.

In short it is half-way to technical and similar to Advanced Nitrox.

Sure its not for everyone - it has been hard to find anyone in the UK teaching it and our motivation has been to do a course that did not require doubles, with the extra weight and cash that this implies. To comply with the redundancy you need a H valve on the tank and these are not common in the UK either (although standard in much of mainland Europe).

I am fascinated by the technical side of mixed gas diving and would do the course for that alone. My wife gets a bit narked at depth and we believe the Helium will help with that - if it does not I will post up for your education...

Chris.

 

[MHK]

I don't know if the class requires redundancy or not.

.

Mike,

This class has a depth range of 80' - 120' and then the standards provide for a +/- 10'. Meaning that on the deep end a diver could reach 130' within standards and on the shallow end a diver could be at 70' on a 32% Nitrox. Accordingly, given that it's possible, for example, that a diver could be in Cayman at 70' on a 32% mix we felt that it might be overkill to require the use of doubles for this type of dive. One of the area's that we spend a great deal of time on is gas management and what divers will aprreciate during the class is the lack of adequate gas supply for OOA's in the 120' range using a single tank and as a result we strongly recommend doubles for those type of dives. Remember, we are trying to teach divers how to think, and and how to plan, their dives and provide them with the tools necessary to properly plan dives in the ranges of 80'-120'. In some instances a single tank if more then sufficent, whereas other dive doubles would be more appropriate..

Hope that helps..

Later

 

[BigJetDriver]

Other agencies are jumping on the recreational trimix band wagon also. IANTD and NAUI both have classes.

Helium is just another tool. The main focus is, I think, skill development.

Just as a note, Mike, IANTD has had tri-mix classes longer than any of the other agencies. It's a matter of emphasis, though. Sometimes we forget that ALL of the diving we do, whether we are above or below the "magic" 130 fsw mark, and no matter what we are breathing, is recreational diving by its very definition.

Only if we are doing Public Safety Diving of some variety, or a contracted and paid commercial diving job of some kind (and scientific research diving for pay fits in here) are we doing something OTHER than recreational diving.

Your point about helium being a tool, and skill development being the focus is very well put!

BJD :anakinpod

 

[reubencahn]

I'm planning on taking this class in the spring having recently completed the DIR-F. I'm a recreational diver, no present interest in tech, and to me this is GUE's AOW class. I found DIR-F to be a great class with not one minute of time wasted--and we used much more time than scheduled for the class. Yet there was a good deal of material that I wish there had been more time to cover, either in detail or at all. I figure I'll get that time during this class. Am I buying a card? I don't think so. I managed to go the last 16 years without buying other cards. Perhaps I'm only purchasing class and dive time with the GUE instructor who taught my DIR-F. I can't imagine that will be a waste of money.

As to triox, I have only minimal interest in it. It is expensive--though FillExpress charges only $.028 per cu/ft on a fill card and charges you only for the gas actually purchased. More important, I don't do a lot of diving in the 100 to 130 ft range. There's just not a lot to see down here at those depths except a couple of reefs up in WPB. There are a lot of deep wrecks but they're deeper than that and I don't have that much interest in wrecks anyway. But triox is a tool that GUE thinks is useful, and, so far, I've seen nothing to lead me to doubt GUE's reasoned judgment on anything connected to diving. In any case, knowledge about triox isn't going to hurt me.

Once I've taken the course, I'll report back whether it was worth it.

 

[Big-t-2538]

This also is ignoring the very real issues with faster diffusion (in both directions) for He, and the attendant higher risks of AGE or DCI if you must make an ESA when diving on He based gasses.

IMHO it is irresponsible to teach this class outside of the context of training divers to be fully redundant and to solve all problems underwater; as far as I'm concerned diving a He-based mix is identical to doing a deco dive, even within the NSLs, as the option of a CESA now comes with an increased risk of injury.

How in the world can you possibly make these statements without having taken the class itself? I don't mean to be a prick...but those are awfully bold statements unless you provide us with some substantial experience.

 

[hijumpr]

I can tell you that I took this class both as a introduction to Tech1 and as the follow on class to DIR-F. We learned far more than just about utilizing 30/30 as a tool below 80ft. My focus was on being a better diver, period. This class definitely helps to make you a better / safer diver at 80-120ft. Here is my Trip Report from our class http://www.scubaboard.com/t40363.html.
Tyson

 

[Genesis]

How in the world can you possibly make these statements without having taken the class itself? I don't mean to be a prick...but those are awfully bold statements unless you provide us with some substantial experience.

The faster diffusion is a physical fact; there is no "experience" needed (do you need to HAVE an AGE to know what can CAUSE an AGE? I hope you're not arguing that!)

My point here is simple, and its one that I aired out with Kane on another board a few months ago - and which he was never able to respond to with more than unbridled bald assertion.

1. In the range where a CESA is "reasonable" (say, < 60-80') Triox provides zero benefit to the diver on any objective basis. It is, however, significantly more expensive to dive than Nitrox. Therefore, there is no reason on God's Green Earth to dive it at those depths.

2. In the range where a CESA is "more dangerous" (say, 80-130') Triox MAY, for some certain individuals, provide a narcosis benefit, particularly deeper than 100'. HOWEVER, a "blow up" ascent from 100'+ on any gas is dangerous, and the simple physics say that one on Triox is really dangerous, especially from shorter dives at deeper depths (still within the NDLs) where you have more "fast" tissue loading (those tissues will release the gas the fastest too!)

3. The next argument Kane made was that there was a CO2 loading benefit that made it worthwhile. I challenged him to provide any scientific evidence of this (e.g. even dry chamber dives in which CO2 loading was monitored on Triox .vs. Nitrox.) He was unable to do so, simply falling back on the density difference and theoretical modelling from a 30 year old study, which did not actually test the hypothesis. The problem with this is that density is not the entire issue; below a certain work of breathing/work rate combination there is no issue with CO2 loading - above that point there can be.

4. GUE eschews pony bottles by dogma. As such the only "legitimate" option for dives below where you can comfortably make an ESA is, realistically, doubles. By teaching this as a gas for diving beyond the reasonably safe ESA limit (on that gas) without doing so in doubles, there is an inherent conflict. Unfortunately, there is no rational argument for a benefit of Triox above the ESA limit, which means that, at least from where I sit, the class syllabus makes no sense.

5. Single tanks - particularly single AL80s - do not have a safe reserve available below 100' for virtually all divers if you must provide gas for your buddy. This is predicated on TWO divers making a safe, normal ascent. Diving a single AL80 on "thirds" (to make such an ascent "safe" in a donor situation) on dives of 100' or more basically means turning the dive when you get there, for all intents and purposes. While you can dive an AL80 in OW below 100', what you can't do is dive that same tank and yet provide TWO divers with a slow, safe ascent rate with stops, especially if one of you is stressed and breathing at above your normal rate - you will be forced to blow off at least some of your scheduled stops if you must donate air in such a situation.

From my perspective, at least, the "crossover" point between recreational and technical diving is not the presence of an overhead (virtual or real.) It is the point at which your open water training - that an ESA is a reasonable option - goes out the window and is replaced by the dogma that one must solve problems underwater, and that an ESA is a last ditch effort to avoid what is otherwise certain death, with full knowledge that (1) it might kill you anyway, and (2) if it doesn't it is extremely likely to hurt you badly, with a good probability that your diving days are permanently over.

This perspective shift ends up driving your equipment choices, and for dives below 100' or so simply dictates that doubles be taken.

This is a vastly different perspective than what is taught in any "recreational" class.

IMHO Triox is a "quasi-technical" class as the benefits of the gas really don't show up until you're below 100', and with the faster diffusion "blow up" ascents from that depth on it are not an acceptable response to a problem.

It should thus be taught with some form of gas redundancy as a requirement (beyond your buddy), and since GUE disqualifies pony bottles out-of-hand, this means doubles.

 

[MikeFerrara]

1. In the range where a CESA is "reasonable" (say, < 60-80') Triox provides zero benefit to the diver on any objective basis. It is, however, significantly more expensive to dive than Nitrox. Therefore, there is no reason on God's Green Earth to dive it at those depths.

The class deals with diving down to 120 ft. I don't know that they are suggesting the 60 ft dives should always be done with triox. Helium is just a tool that they're introducing to be applied to diving down to 120 ft.

2. In the range where a CESA is "more dangerous" (say, 80-130') Triox MAY, for some certain individuals, provide a narcosis benefit, particularly deeper than 100'. HOWEVER, a "blow up" ascent from 100'+ on any gas is dangerous, and the simple physics say that one on Triox is really dangerous, especially from shorter dives at deeper depths (still within the NDLs) where you have more "fast" tissue loading (those tissues will release the gas the fastest too!)

No argument there. Rapid ascents are bad

3. The next argument Kane made was that there was a CO2 loading benefit that made it worthwhile. I challenged him to provide any scientific evidence of this (e.g. even dry chamber dives in which CO2 loading was monitored on Triox .vs. Nitrox.) He was unable to do so, simply falling back on the density difference and theoretical modelling from a 30 year old study, which did not actually test the hypothesis. The problem with this is that density is not the entire issue; below a certain work of breathing/work rate combination there is no issue with CO2 loading - above that point there can be.

I have seen divers panic and say later that they felt out of breath. I suspect that CO2 was at least part of the problem but I couldn't prove it. Helium might have helped and so might better technique because these are usualy divers that are working hard. Also there is the contribution of CO2 to narcosis which I would guess is a hard thing to quantify in a study.

there just aren't all that many studies because nobody cares enough about this to spend any money on it. If we wait for studies to make decisions we'll be frozen still.

4. GUE eschews pony bottles by dogma. As such the only "legitimate" option for dives below where you can comfortably make an ESA is, realistically, doubles. By teaching this as a gas for diving beyond the reasonably safe ESA limit (on that gas) without doing so in doubles, there is an inherent conflict. Unfortunately, there is no rational argument for a benefit of Triox above the ESA limit, which means that, at least from where I sit, the class syllabus makes no sense.

5. Single tanks - particularly single AL80s - do not have a safe reserve available below 100' for virtually all divers if you must provide gas for your buddy. This is predicated on TWO divers making a safe, normal ascent. Diving a single AL80 on "thirds" (to make such an ascent "safe" in a donor situation) on dives of 100' or more basically means turning the dive when you get there, for all intents and purposes. While you can dive an AL80 in OW below 100', what you can't do is dive that same tank and yet provide TWO divers with a slow, safe ascent rate with stops, especially if one of you is stressed and breathing at above your normal rate - you will be forced to blow off at least some of your scheduled stops if you must donate air in such a situation.

Past 100 ft you don't have gas for much of a dive with a single 80 given how they teach gas management so I'd bet that most if not all the students are in doubles or big tanks with H-valves when they do the deeper dives.

From my perspective, at least, the "crossover" point between recreational and technical diving is not the presence of an overhead (virtual or real.) It is the point at which your open water training - that an ESA is a reasonable option - goes out the window and is replaced by the dogma that one must solve problems underwater, and that an ESA is a last ditch effort to avoid what is otherwise certain death, with full knowledge that (1) it might kill you anyway, and (2) if it doesn't it is extremely likely to hurt you badly, with a good probability that your diving days are permanently over.

This perspective shift ends up driving your equipment choices, and for dives below 100' or so simply dictates that doubles be taken.

This is a vastly different perspective than what is taught in any "recreational" class.

Not very different from my classes. LOL I don't teach any class that requires students to go below 100 ft on a single tank with out redundancy and I don't recommend any one do it. ESA's are always a last resort.

IMHO Triox is a "quasi-technical" class as the benefits of the gas really don't show up until you're below 100', and with the faster diffusion "blow up" ascents from that depth on it are not an acceptable response to a problem.

It should thus be taught with some form of gas redundancy as a requirement (beyond your buddy), and since GUE disqualifies pony bottles out-of-hand, this means doubles.[/QUOTE]

"Technical", "quasi-technical"...who cares? As far as I'm concerned we should get rid of the term.

 

[jeffkruse2000]

That last post seams to be a anti DIR post and had little to do with Trimix.

I dive Trimix all the time. Anything over 60' and I like 30/30. It's easier to breath and generally makes me feel better.
I have been diving Trimix since March. Right away I stopped diving air.

I pay $55 - $70 for 300cf of He. That's about 20 cents a cf. A 30/30 fill in a HP100 tank is $6 worth of He and a buck of O2. My total price for fill a empty single tank of 30/30 is under $10. Since I CB I only pay for gas I use. Always coming back with 500 - 1000psi and my fill price is under $8. I think I am paying a normal price for He in the US.

My question is why would I not dive Trimix for dives deeper than 60' ?

The "NDL" for 30/30 is such that by following my RB on a single 100cf tank I would be hard pressed to approach those limits. None the less I always do 10' a minute from 40' and up.

It just makes me feel better.

Jeff
My web site: http://www.seanet.com/~katrinakruse/