DIR- GUE Is it worth taking Fundamentals this late in the game?

[justinthedeeps]

Another funny one, that is apparently ongoing in the nitrox thread, is some GUE people religiously clinging to the assertion that oxygen is narcotic.

And yet, these same GUE divers are also happy to breathe 100% oxygen at 6 metres / 20 feet, a ppO2 of 1.6--the maximum--with no concerns or experiences of narcosis. This absolutely contradicts the "oxygen is narcotic" claim.

Contrast to a typical TDI, PADI, SSI, IANTD culture where it's like ok here is what we think is a good way to do this, but we aren't acting like God giving the Ten Commandments (that's more of a GUE thing).

 

[Nick_Radov]

Like when I try to explain things as simple as why and where an 80% nitrox actually works in certain deco plans--with actual data on stop depths and runtimes. Instead of them thinking about it at all, it's just this canned unthinking response of "GUE uses 100% only, so I pity you, you must be wrong"

If you torture your deco planning software enough you can probably come up with some unlikely profile where an 80% deco mix appears to get you out of the water a few minutes faster than 100%. But this rather misses the point. By using a consistent set of standard gasses, we can apply clear, permanent stage tank markings and be sure that our buddies are doing things the same way. If we have to change dive plans at the last minute, then it's easy to adapt without having to remix fills. And if someone needs oxygen first aid, well you've got it right there in your deco stage.

The original reason stated by some incompetent dive instructors for using 80% was to avoid toxicity incidents with students who couldn't hold a stable 20ft / 6m deco stop. Obviously, that's ridiculous because students with poor buoyancy control shouldn't be doing deco dives in the first place.

 

[wetb4igetinthewater]

Another funny one, that is apparently ongoing in the nitrox thread, is some GUE people religiously clinging to the assertion that oxygen is narcotic.

I just woke up and did a quick search for this: Is Oxygen Narcosis A Thing?

My interpretation (not a scientist) is that oxygen is narcotic

And yet, these same GUE divers are also happy to breathe 100% oxygen at 6 metres / 20 feet, a ppO2 of 1.6--the maximum--with no concerns or experiences of narcosis. This absolutely contradicts the "oxygen is narcotic" claim.

Where is the contradiction? Nitrogen is narcotic. I think none of us disagree. Oxygen per my understanding is narcotic. What is the difference in narcosis (gross assumption that nitrogen and oxygen are somehwat equally narcotic) between breathing air at 6 meters and pure oxygen at that depth?

What exactly am I missing? (sincere question)

Contrast to a typical TDI, PADI, SSI, IANTD culture where it's like ok here is what we think is a good way to do this, but we aren't acting like God giving the Ten Commandments (that's more of a GUE thing).

The GUE standardization of gasses just makes it easier for planning. Are they perfect gasses for every dive? Of course not. However, they make it simpler for team members showing up with the same mixture as the gasses are understood.

 

[justinthedeeps]

If you torture your deco planning software enough you can probably come up with some unlikely profile where an 80% deco mix appears to get you out of the water a few minutes faster than 100%. But this rather misses the point.

On the contrary, it is a rather pleasant exercise. Simply consider an 80% on a Mod3 dive in the planner as an option. Nobody is going to force you to use it. But it becomes quite quickly apparent that all of a sudden, your entire time at ~9 metres can be on a better deco gas than 50%. This actually can make a big difference in gas planning and runtime results, depending on the dive.

The problem with the GUE way is that it is considered heretical to even type 80% into a computer. Burn the keyboard!

By using a consistent set of standard gasses, we can apply clear, permanent stage tank markings and be sure that our buddies are doing things the same way.

Mate, I know the GUE propaganda, believe me, they never stop talking about it.

I've been on multiple very well planned dives to 100 metres where we calmly and rationally chose 80% as a final gas, as a "unified team." There was nothing wrong with this, and in fact it gave us better runtimes and gas planning in those cases. I find it sad that GUE isn't training its divers to be logical and versatile.

If someone needs oxygen first aid, well you've got it right there in your deco stage.

So again you're making an assumption that --only-- 100% is helpful as first aid. I am not sure that is entirely true.

But yes it is good to have therapeutic oxygen on board. Any serious dive boat, LOB or centre will have that, in an actual first aid configuration (flow rate control, passive delivery mask, etc)

The original reason stated by some incompetent dive instructors for using 80% was to avoid toxicity incidents with students who couldn't hold a stable 20ft / 6m deco stop. Obviously, that's ridiculous because students with poor buoyancy control shouldn't be doing deco dives in the first place.

Highly dubious claim. We are aware of GUEs opinion that only GUE divers can hold stops correctly (also false). But there are in fact other reasons to consider 80%. Lower CNS. Gets you off the 50% sooner. Consumes less 50% in the process. Same maximum off-gassing gradient for helium as 100% (since they both contain no helium).

I think 100% is very useful and valid too.

I would never give up my willingness and permission to actually think through this with an open mind. That is where GUE differs, apparently.

 

[justinthedeeps]

My interpretation (not a scientist) is that oxygen is narcotic

Nobody seems to be able to point to any clear evidence that oxygen itself is narcotic. I and others breathe a ppO2 of 1.6 quite often on a rebreather, during oxygen flushes and accelerated deco. "The maximum" for ppO2. And people do it all of the time on open circuit 100% oxygen. Nobody is getting narc'ed from that. That IS the test. Gases affects us via partial pressures, independently of other gases.

Next time you get narced off oxygen, maybe measure what else is in there that you didn't consider. Argon, CO2, CO...?

What exactly am I missing? (sincere question)

That makes two of us... but apparently the only two.

Others still seem sure that 100% oxygen is narcotic, despite zero evidence or experience to support that using modern high quality oxygen sources. Weird.

The GUE standardization of gasses just makes it easier for planning. Are they perfect gasses for every dive? Of course not. However, they make it simpler for team members showing up with the same mixture as the gasses are understood.

Logistics should definitely be kept simple. Standardization is great when you're running a shop, curriculum, expedition etc. GUE isn't wrong at all about that. GUE is doing that right. No more sh!tshows! Amen to that!

That said, I don't think I am alone in saying that I regularly get this weird and unthinking "everyone else is wrong and ignorant" vibe from GUE fundamentalists.

 

[elmo]

Another funny one, that is apparently ongoing in the nitrox thread, is some GUE people religiously clinging to the assertion that oxygen is narcotic.

And yet, these same GUE divers are also happy to breathe 100% oxygen at 6 metres / 20 feet, a ppO2 of 1.6--the maximum--with no concerns or experiences of narcosis. This absolutely contradicts the "oxygen is narcotic" claim.

Contrast to a typical TDI, PADI, SSI, IANTD culture where it's like ok here is what we think is a good way to do this, but we aren't acting like God giving the Ten Commandments (that's more of a GUE thing).

Ok I’ll play. I breathe 100% O2 at 6m and feel zero narcosis. Does that mean O2 isn’t narcotic? I breathe air at 6m and feel zero narcosis. Does that mean N2 isn’t narcotic either? The comparison proves nothing.
To do a meaningful comparison we could test air vs pure oxygen at 40m. One gas would make me narced and the other would probably kill me. I’m not going to do that experiment.
Unless you’re my buddy I really don’t mind if you dive with 80% as a deco gas. And I really won’t mind if you get out of the water before me.

 

[justinthedeeps]

Ok I’ll play. I breathe 100% O2 at 6m and feel zero narcosis. Does that mean O2 isn’t narcotic? I breathe air at 6m and feel zero narcosis. Does that mean N2 isn’t narcotic either? The comparison proves nothing.
To do a meaningful comparison we could test air vs pure oxygen at 40m. One gas would make me narced and the other would probably kill me. I’m not going to do that experiment.
Unless you’re my buddy I really don’t mind if you dive with 80% as a deco gas. And I really won’t mind if you get out of the water before me.

I'm with you on this urge to think up some kind of "at depth" of "additive" example for the effects of oxygen at depth. I am just not aware of theory or evidence that explains or supports it.

I guess the "oxygen narcotic" theory proposes that you just add the ppO2 onto the ppN2 to get some kind "combined partial pressure" for narcosis. But that kind of violates other theory which says gases don't "see each other," or interact or combine like that.

Oxygen molecules behave quite differently from nitrogen ones in the body. This is one reason why we don't get oxygen bends.

The ppO2s are also never above 1.6atm. While nitrogen, known to be bery narcotic, /begins/ to be narcotic at ~2.4+atm. Regardless of how narcotic oxygen actually is, it will always be a minor fraction of the total gas at depth.

I am not that surprised that people still feel narc'ed even on "clean" EAN32 at 33 metres. There is still a buttload of narcotic nitrogen in it. The ppN2 alone is still around 3.0atm there (4.3atm * 0.68), well into narcotic pressures. You don't need oxygen narcosis to explain why EAN32 is narcotic at its MOD.

 

[justinthedeeps]

GUE scores a win here, by correctly reasoning that adding some helium already makes sense at or below 30 metres. Nitrox is already narcotic there, and the nitrogen alone is probably sufficient to explain why.

21/35 has a ppN2 of only 1.76atm at 30m. Should we count the oxygen in 21/35 as narcotic too? Is that consistent with experience? If true, we should start getting narc'ed on 21/35 as shallow as ~36 metres (3atm/.65 -1)*10. That doesn't quite sound right to me.

To trigger further barfs from some people, mixes like 20/20 are common enough in many helitrox courses to 45 metres these days to also call it a "standard gas"--just not GUE's standard. ppN2 is 3.3atm there, quite close to the ppN2 of air at 30 metres. People aren't getting terribly narced on that mix and depth.

 

[justinthedeeps]

So, per OP, "is it worth taking Fundamentals this late in the game?"

I think you can see that depends on how much you like your independence as a diver and freedom of thought. There will be excellent skills work, but there will also be some pretty hard minded dogma that is not always open to doubt, alternatives, or unbiased analysis.

 

[steinbil]

So, per OP, "is it worth taking Fundamentals this late in the game?"

I think you can see that depends on how much you like your independence as a diver and freedom of thought. There will be excellent skills work, but there will also be some pretty hard minded dogma that is not always open to doubt, alternatives, or unbiased analysis.

I'm curious, have you ever taken a GUE class?

I understand that some GUE divers, probably mostly newer fresh out of fundies and especially on the internet, give the impression that they 'know it all' and uncritically follow the holy script of GUE and think all others to be heretics, yadda yadda. I'm not trying to discredit that those divers exist or that some people might have bad experiences with them.

However, my experience is quite different. Almost without fail, the GUE divers I've met are friendly, open minded, non-dogmatic, pragmatic and just fun people to dive with. They're not uptight, judgemental or sticklers for strict procedures. Actually the more experienced they are, and the instructors, seem to be the most open minded, relaxed, knowledgeable and practical.

Yes there are some standards that are upheld, but they are open to discussing them, very clear on why they dive the way they do, and have a lot of experience of serious dives with a rationale for why the standards make their dives easier, more enjoyable and safer.

I dive regularly with both GUE divers and divers from other agencies, and I don't mind, as long as I can trust them and they are competent at the level we dive.

Actually I hear a lot more negative things about GUE, similar to what you describe, from non-GUE divers than I hear negative things about other agencies from GUE divers. So I'm wondering how much is based on actual experiences and how much is just talk...