Why do you dismiss DIR?

[newton]

Originally posted by Uncle Pug

Cold water + exertion = CO2 buildup
CO2 build up increases the chance of an O2 hit.

So keep the PO2 lower.

Ahh. Now *THIS* is something that I can hang my hat on. You are correct, I *did* have it backwards.

This entire DECO theory is pretty funky. You have to juggle all sorts of things to provide the 'optimum' safety for yourself.

You want to decrease N2, which usually means to increase O2. However, too much O2 is bad because of CNS, and too much O2 is bad under high stress/high workloads because of CO2 buildup. Helium is great, but it is expensive, and it almost always introduces some deco obligations (even at shallower depths).

So, we swap higher percentages of O2 to have less N2, but don't want to go *too* far to avoid CNS and CO2 buildup.

Wouldn't it be nice if there was *one* single mixture that was best for all depths. Or better yet, a system that would automatically determine the best mix for you for any depth automatically (kind of like a rebreather does, but w/out all the hassle/dangers of one now.)

I can see something like this in about 15-20 years. But, for now I think we can all agree that this is certainly a 'technical diving' topic.

Thanks for all your input Uncle Pug, it's been invaluable!

 

[Uncle Pug]

Originally posted by newton

True, but the decrease in PPN2 over the lifetime of the dive may decrease the risk of DCS. Especially if you use the 20% rule. (Again, I'm assuming that the O2 CNS clock is *rarely* an issue for the types of dives that are done with EANXX, vs. the use of tri-mix or heliox).

Nah... you got it backwards.... DCS isn't the issue of concern here... any time higher than normal PO2s are involved OxTox has got to be considered.... whether CNS or Pulmonary.

So, in summary I believe that EAN32 is a *good* choice for a standard mix, but I don't believe that it's a better choice than EAN34 is, from a technical perspective.

Newt... your just talking to hear your head rattle... give it up dude... I know you see the light

(My suspicion for the choice is that some of the caves the WKPP folks were diving had a hard bottom that was slightly lower than 100', so EAN34 may not have been a great gas early on for some of the support divers, so they standardized on EAN32. Then again, I'm probably completely out to lunch.

You never heard of NOAA 1 and 2 ??? BTW: what's for lunch?

 

[Uncle Pug]

Originally posted by newton
Helium is great, but it is expensive, and it almost always introduces some deco obligations (even at shallower depths).

I was going to mention something about this from a previous post of yours but forgot..... No, Helium is not bad... it is very good. It goes in and comes right back out of tissue faster that nitrogen but without the damage.... with the exception of one tissue... FAT! It still goes in fast but it comes out slower than it went in. I don't want to get in to deep with you here so I will give the clue in a PM

Wouldn't it be nice if there was *one* single mixture that was best for all depths. Or better yet, a system that would automatically determine the best mix for you for any depth automatically (kind of like a rebreather does, but w/out all the hassle/dangers of one now.)

Or, since there isn't... how about a series of standardized mixtures covering a range of depths? I was thinking along the lines of:
0-100 EAN32
80-120 30/30Tx
120-160 21/35Tx

 

[Scottri]

To me it's not a matter of merit. I just hate the fact that so many practitioners of DIR are so damned judgemental. I agree that there is a lot to be said for DIR but I get tired of being lectured on my gear configuration. My gear configuration is right for me period. If it's not right for you don't use it. Just don't sit there next to me on the beach or boat and ramble on about your superior gear configuration because I don't want to hear it. To me it's the same thing as having Mormons come to my door on a Saturday to convert me. I don't dislike the religion, I just dislike the intrusion.


Scott

 

[Uncle Pug]

Originally posted by Scottri
I don't dislike the religion, I just dislike the intrusion.
Scott

Shoot Scott.... I'm sorry.... I didn't know there were anymore diatribes coming and we hijacked this thread into somewhat of a little explaination of the whys and where fores of EAN32....

Let it out buddy... I hear ya...

 

[VTWarrenG]

Scottri,

I assume you don't conduct technical or overhead dives. If you do, I would hope that you'd understand that the "gear configuration that's right for you" might kill you.

Very few DIR divers have much to say about open-water recreational diving. Open-water rec diving isn't dangerous, and doesn't demand special equipment or procedures beyond those learned in basic open-water class. If you choose to dive DIR in open water, that's great... but it doesn't really matter there.

A common theme I've observed is that many divers have no idea what is required to safely conduct deep, overhead, or otherwise technical dives. They are ignorant of the extent of those challenges, and therefore they don't appreciate DIR -- they think DIR is just some "marketing ploy" or "elitist movement" or "religion."

So fill us in -- who lectured you? Who tried to convert you? What did they say or do?

I don't dislike the religion, I just dislike the intrusion.

So you like DIR, but don't like the DIR divers you've met. If I may paraphrase, you resist adopting a diving style that you recognize is safer and more effective than "what's right for you" because someone got on your nerves about it. That's unfortunate.

- Warren

 

[Uncle Pug]

Yup... you were right....
now we gotta go find a place that isn't all silted out to have our learnin' sessions.
When you boys get done wrestling the the shallows let us know.

 

[VTWarrenG]

Pug,

You got a point. I stand down. It's a common theme that people don't want to even consider DIR because they don't like the attitude of a small minority of overly-vocal DIR divers -- and that makes me mad.

My apologies.

- Warren

 

[Scottri]

VTWarrenG,

I don't dive in overhead environments and I'm not a "tech" diver. My gear configuration is standard for recreational divers. If I were to get into more technical diving I would of course seek training and purchase the necessary gear. I don't resist changes to my setup soley because it is "DIR". I am just tired of perhaps a vocal few DIR folks that put me off. I will agree that there is merit to DIR and I will adopt what fits my diving but not just because it is DIR.


Scott

 

[Uncle Pug]

Sheesh... must be a case of reasonableness going around...

You guys sure got over that fast!

Well... I gotta go for a while so we see what things look like when I get back....