'Non' DIR or DIR diver?

[fweber]

This little helium side note, has my interest. On a 30 meter dive, the difference in END between 30/30 and EAN32 is around 6 meters. 18m vs 24m, give or take, without getting into a debate about narcotic properties of Oxygen. From a narcosis standard point this represents to me, the difference between shallow and really shallow. I recognize some individuals desire to dive in what they consider to be the safest possible manner. However, I have to question what is "safe enough"? And, what is a sufficiently shallow END? If you were to draw an analogy to auto driving. If excessive speed is dangerous, and if it is safer if you slow down, at what point do you either start to represent the driver going 35 on the freeway and posing a greater hazard to all, or does everyone slowing down in the quest for ever greater safety cause the mode of transport to fail in it's intended purpose?

To, Bob and Doug, thanks for the thoughtful discussion. I'm sorry I had to go work on the boat yesterday. I started to compose a brief discussion of my views, but then read the link to Trace's experience and some of the other points presented on TDM and XForums. While I have a couple things that could be added from my particular perspective, they really don't strike at the heart of the issue any better than already done by others.

 

[Jason B]

I use 30/30 on my cave dives in the 100ft range. Really clears the head and as a side benefit in high flow, the regs breathe great (helping prevent CO2 issues).

To each his own. No one is asking or forcing you to do so - please allow us the same consideration.

As for it being pricey - mix your own, kinda becomes a no-brainer at that point.

 

[John_B]

... nevermind, not worth the effort ...

 

[Adobo]

If you were to draw an analogy to auto driving. If excessive speed is dangerous, and if it is safer if you slow down, at what point do you either start to represent the driver going 35 on the freeway and posing a greater hazard to all, or does everyone slowing down in the quest for ever greater safety cause the mode of transport to fail in it's intended purpose?

Sorry, how does a team's choice to use 30/30 instead of 32 on a 100ft (30m) dive affect other's safety?

 

[Dan Gibson]

+4 = HFS

The problem with +2 applied universally to every diver is that many divers simply need a more conservative setting, such as +3 or +4 etc.

 

[ScubaAndDreams]

I'm also curious if people really use helium in the 80 - 120 range? I'm fairly new and I was under the impression that helium was only used much deeper than this.

My choice of gas (and my regular teammates) on a wreck penetration dive in the 100ft range is 25/25. I have enough stuff to worry about during a penetration dive without needing/wanting the added issues that come with narcosis.

It really comes down to "How much risk are you willing to take?" Everything else follows from there...including if your teammates are comfortable with that choice...

 

[MXGratefulDiver]

The sheer arrogance of this statement rivals anything I've read on this forum.

It also demonstrates how arrogance and ignorance are often conjoined ... since, to anyone who actually understands the topic, it is obvious that the person who posted it doesn't know what he's talking about ... either that or he's just a poor fisherman ...

... Bob (Grateful Diver)

 

[MXGratefulDiver]

This little helium side note, has my interest. On a 30 meter dive, the difference in END between 30/30 and EAN32 is around 6 meters. 18m vs 24m, give or take, without getting into a debate about narcotic properties of Oxygen. From a narcosis standard point this represents to me, the difference between shallow and really shallow. I recognize some individuals desire to dive in what they consider to be the safest possible manner. However, I have to question what is "safe enough"? And, what is a sufficiently shallow END? If you were to draw an analogy to auto driving. If excessive speed is dangerous, and if it is safer if you slow down, at what point do you either start to represent the driver going 35 on the freeway and posing a greater hazard to all, or does everyone slowing down in the quest for ever greater safety cause the mode of transport to fail in it's intended purpose?

To, Bob and Doug, thanks for the thoughtful discussion. I'm sorry I had to go work on the boat yesterday. I started to compose a brief discussion of my views, but then read the link to Trace's experience and some of the other points presented on TDM and XForums. While I have a couple things that could be added from my particular perspective, they really don't strike at the heart of the issue any better than already done by others.

As stated, my choices of breathing gas shouldn't have any effect on any other divers in the water except the one(s) on my team ... in which case, depending on the dive, it may be sensible to gas match. And in any case, I don't see how my choice of gas can be couched in terms of how it affects the safety of anyone except myself.

As for costs, it's often the case that I'll end a tech dive with 1500 to 2000 psi of something like 18/45 or 21/35 in my doubles. Topping them off with EAN32 usually creates a nice recreational mix that's suitable for some of the dives I do in the 100-120 range, and it costs me nothing extra ... it's just a way to make good use of the reserves I didn't need for that last tech dive.

... Bob (Grateful Diver)

 

[TSandM]

END calculations are done differently by different people/agencies. GUE regards both nitrogen and oxygen as narcotic, and therefore the END of 32% is your actual depth. Therefore there is a significant reduction in END with 30/30 as compared with 32%.

 

[dsteding]

This little helium side note, has my interest. On a 30 meter dive, the difference in END between 30/30 and EAN32 is around 6 meters. 18m vs 24m, give or take, without getting into a debate about narcotic properties of Oxygen. From a narcosis standard point this represents to me, the difference between shallow and really shallow. I recognize some individuals desire to dive in what they consider to be the safest possible manner. However, I have to question what is "safe enough"? And, what is a sufficiently shallow END? If you were to draw an analogy to auto driving. If excessive speed is dangerous, and if it is safer if you slow down, at what point do you either start to represent the driver going 35 on the freeway and posing a greater hazard to all, or does everyone slowing down in the quest for ever greater safety cause the mode of transport to fail in it's intended purpose?

Interesting point, and one that the answer will probably cause some breakdown of the perceived rigidity of GUE/DIR approaches to diving. There are certainly dives that I could see doing in the ~100 foot range where helium is needed for me, for instance, the cold (43 degree), dark (think no ambient light), low-vis (~2-3 foot) bottom of Lake Washington. There I'd want a very clear head. Or, as others have mentioned, in caves or wrecks. Note that I don't have triox training yet, but having been to those depths on nitrox, I can see the value of adding helium as the complexity of the dive increases. So, whether you dive 30/30 to 100 feet or 32% to 100 feet depends on the dive . . .

As for a max END of 100 feet in general, while some may see it as a bit too conservative, I really don't think erring on the side of conservative in diving is a bad thing. Sure, you can run things out to absurdity, but one take-away I've gotten from my GUE training so far is to (a) assess the risks; and (b) make informed decisions based on those risk and your skills. Those twin principles are the bedrock of my dive planning.

When viewed in the above light, I think your highway analogy breaks down. Effective rhetoric for sure, and as an attorney, I admire your application of it here. If I was a drone mindlessly following the dictates of my agency, maybe that would have merit. But, I'm not--and GUE training has emphasized the need for me to be a thinking diver. So, I wouldn't, so to speak, slow down until I create more issues. Instead, I'd strike a balance between the needs of the dive, the risks associated with the dive, and the resources I have as a team and in terms of personal skills.

Make sense?

To, Bob and Doug, thanks for the thoughtful discussion. I'm sorry I had to go work on the boat yesterday. I started to compose a brief discussion of my views, but then read the link to Trace's experience and some of the other points presented on TDM and XForums. While I have a couple things that could be added from my particular perspective, they really don't strike at the heart of the issue any better than already done by others.

I've read Trace's posts, and they are quite informative. I'll add that my experience with GUE has been a bit different. With an engaged, local, instructor, I find myself able to be mentored and I have the ability to work with Steve on a fairly regular basis. There is also a growing community of GUE and NAUI DIR divers locally, and that community has been a positive resource for me personally.