Skipping surface intervals - DIR or not?

[*Floater*]

If SIs were not needed, we would not have recommendations to not over exert ourselves/exercise after dives. Also that 107deg hottub would be okay.

Yes, I was told not to exercise after diving by my instructor. I later asked by email why that was prohibited but flying and repetitive dives were okay. I didn't get a reply that time, but later he repeated the advise about not to exercise after diving. Maybe it's something that GUE requires their instructors to teach even though some may not agree. Here's a quote from George Irvine's deco theories that suggests exercise after diving may be okay for some people, though he acknowledges it's risky:

If you execute deco correctly and are in good shape and have no preconditions, you should be clean and ready for anything 30 minutes after you get out of the water. You can tell if you have not done what I am saying here, you will not feel so good. It will be subtle, but if you want to test it, try going for a run. If you are immediately short of breath, you blew the deco. If you can rock, you did it right. If you get bent trying this, then tough luck, blame JJ. In reality, you will feel a little sluggish and heavy just putting your gear away if you did an inadequate deco.

 

[Doc Intrepid]

Yes, I was told not to exercise after diving by my instructor. I later asked by email why that was prohibited but flying and repetitive dives were okay. I didn't get a reply that time, but later he repeated the advise about not to exercise after diving. Maybe it's something that GUE requires their instructors to teach even though some may not agree. Here's a quote from George Irvine's deco theories that suggests exercise after diving may be okay for some people, though he acknowledges it's risky:

Q. When is a theory not just a theory?

A. When testing that theory personally can put you in either a chamber or a wheelchair for the rest of your life.

Planning to conduct two deep decompression dives with no surface interval beyond that time required to switch tanks is ludicrous.

Planning to deliberately conduct staged decompression dives with significant exposures in terms of duration and depth, and then immediately climbing onto an airplane, is farm-animal stupid.

The Risk/Reward Ratio is skewed far out of balance.

There may be times in your lives when you MUST take a risk, for whatever reason. Fine. It happens.

But to deliberately plan to take outrageous risks, with such potentially permanent consequences, for no particularly urgent reason is beyond-the-pale foolishness.

I don't care what George says. You're not George.

As Mer noted, the same diver can conduct the same dive on two different days and be fine one day and bent the next. And Mer knows exactly what she's talking about.

If there is some reason to take a risk, you may need to take the risk.

If there is no need to take a risk, especially one that might land you in a wheelchair, they why deliberately take the risk?

Whats being discussed here is dangerous, and new divers, aspiring technical divers, and brand-new fundamentals divers need to recognize it.

No one, not even George, can tell YOU how YOUR specific tissues will offgas helium and nitrogen during and after any specific dive, conducted on any specific day.

The best lessons in life are either painful, humiliating, or expensive.

Plan accordingly...

 

[Charlie99]

Isn't the DIR forum moderated any more? Aren't there other forums for the bend-and-mend/RDP crowd?

Ummmm. Not all GUE instructors agree with the unnamed instructor you are quoting (or perhaps misquoting).

As for "bend-and-mend/RDP crowd", perhaps you can educate me as to what deco model was used in GUE's Decoplanner software until the relatively recent 3.0 release? Hint: they wax eloquent on how it was used to plan WKPP and Britannic dives, even though it was not a bubble or dual phase model.

Bonus Question: Was Decoplanner 2.0 DIR ???

If you can answer those questions, then go ahead and post about "bend-and-mend/RDP" crowd.

 

[Charlie99]

I *know* you guys understand this stuff. What the heck is it about Floater's idea that's made you forget the foundations of deco theory.....?!

I'm confused.

As are some GUE students, some GUE instructors, or both.

When one newly minted DIR-F grad posts a harebrained (yes, my subjective analysis) idea, I assume that the student wasn't listening, and wasn't provided any written material that would correct his misunderstanding. When mulitple students, from different classes, come up with the same harebrained ideas, one has to look a bit deeper for the source.

 

[StSomewhere]

As for "bend-and-mend/RDP crowd", perhaps you can educate me as to what deco model was used in GUE's Decoplanner software until the relatively recent 3.0 release?

If I'm not mistaken, it was loaded with gradient factors until it was tricked into behaving like a deco program should, was how it was explained to me.

You're spouting off against proper ascent profiles and stops in the DIR forum, so explain how teaching "NDL divers" to optionally pop up to 15' for 3 minutes ala the RDP qualifies as a "safety" stop. Maybe following your beloved RDP people shouldn't fly for 48 hours? 72? More?

Extra credit: Is everything that comes out of High Springs DIR?

 

[Charlie99]

If I'm not mistaken, it was loaded with gradient factors until it was tricked into behaving like a deco program should, was how it was explained to me.


Extra credit: Is everything that comes out of High Springs DIR?

Gradent factors coupled with the neo-Haldanian algorithm (with the particular M-values / ab & b coefficients which happen to be Buhlmann's) or a proper ascent tracked on table based upon another neo-Haldanian model (with DSAT's M-values) are pretty much the same.

You're spouting off against proper ascent profiles and stops in the DIR forum, ........ Maybe following your beloved RDP people shouldn't fly for 48 hours? 72? More?

Maybe you should stop spouting off and read what I wrote.

Perhaps you are referring to my comments about how the ascent taught in SOME DIR-F classes (pause at 80% of ata, then 30 sec move, 30 sec pause every 10' all the way to the surface) is NOT the ideal ascent. Yes indeed, I have stated my belief that this approximation of a 10fpm linear ascent is NOT an ideal ascent. It appears that that is an old GUE recommendation, and has been superceded with a more appropriate recommended ascent profile that spends more time as one get shallow (i.e. shape-of-deco curve)

Do a little research and you will find that this approximation of a 10fpm linear ascent is NOT the best way to come up from a typical recreational depth dive. Perhaps you should read the Ascent from Minimum Deco Dive thread where I asked about that specific subject after a DIR-F grad told me that the tables at www.dir-diver.com and it's 30fpm with 1@40, 1@30', 3@20, 3@10' ascent profile were not DIR.

If you take my comments questioning 10fpm from 80% ata ascent as "spouting off against proper ascent profiles and stops in the DIR forum", so be it.

I do find it somewhat telling that the original poster, who intends or at least seriously contemplated doing repetitive zero SI dives of 100' 30 minutes on EAN32 said that his ascent would be the linear one.

Charlie Allen

p.s. I LOVE my ACB pockets.

 

[TSandM]

I find it sad that none of the GUE instructors who do, from time to time, offer their insights on SB, have weighed in on this thread (eg. MHK, BCS).

The strategy offered by the OP has been seriously criticized by some of our most senior and experienced DIR trained people. Most of the vocal support has come from people who are more like me -- Fundies schooled, or having taken AGs Essentials course.

After my experience in Fundies, I would not open my mouth for a second about what the proper procedure for repetitive diving is, except to ask questions. I got a tiny -- TINY -- glimpse into the GUE thinking about decompression. I'm not sure I got enough to manage my own NDL dives properly, let alone anything more ambitious. If I contemplated anything beyond what I currently do, I'd be signed up for Tech1 to learn more about what GUE REALLY thinks about decompression.

I hope nobody reads this thread and takes away the idea that GUE teaches that it's okay to ignore all the mainstream information about decompression. What George Irvine does, in his perfect fitness and his obvious native aptitude for this sport, and what I can do, at my age and at my fitness level and with my understanding of diving, are two entirely different things. And I doubt GUE is teaching we should all dive to GI3's profiles. Although I don't know, because I'm not that far into the system. And neither are many of the people holding forth on this thread.

 

[WaterDawg]

I think that this thread shows GUE's weakness, lack of after class support, and good manuals.

AG seems to be doing a great job of providing that, maybe the folks in High Springs should look out side everyonce in a while and take notice.

 

[*Floater*]

Interesting links. I was taught the linear ascent method described by MHK below, except I modified the second line slightly:

Use a 30fpm ascent rate;
Initiate deep stops at 80% of ATA;
Continue deep stops using a 30 second stop- 30 second move approach at 10' increments;
Commence your "safety stop(s)" at 30' for 1 minute, then 20' for 1 minute and lastly at 10' for 1 minute

To add conservatism if I went slightly over the table values I was taught to add time to the "safety stops." My instructor also suggested I start the "safety stops" at 40' for dives 3 and 4 if I were to do the repetitive dives to 100' with short surface intervals. (Note: I think the max depth at Abu Nahas is only about 85').

After reading the links I'm guessing the 80% of ATA rule is more about prepping us for future tech diving, than about the optimal ascent curve.

P.S. I said ~15-20 min, never zero. Also, this is all largely hypothetical. Since I'm new to the system I'd start off (given the opportunity) with something more conservative than what I was taught [edit: what I was taught is still okay - I wasn't taught to push the model for the sake of pushing it of course].

P.P.S. I appreciate the concern Doc Intrepid. As I said I'll start off conservatively.

 

[wreckchick]

For anyone who hasn't read it....

http://thedecostop.com/forums/showthread.php?t=3198

Very nice package of information.

R