Skipping surface intervals - DIR or not?

[StSomewhere]

p.s. I LOVE my ACB pockets.

Well that surprises me not at all. :roll:

I still don't get how you espouse these various non-linear profiles but then turn around and defend the RDP just because its what you learned in your PADI DM materials. The two just don't square. You try to build up all this credibility and then you defend the worst possible deco of all (i.e. the "optional" one).

For the record, I never (and you could actually go back and read this for yourself, though you won't) said a zero SI was the right thing. Maybe your so wrapped up in being a legend in your own mind that you forgot who said what?

 

[Charlie99]

I still don't get how you espouse these various non-linear profiles but then turn around and defend the RDP just because its what you learned in your PADI DM materials. The two just don't square. You try to build up all this credibility and then you defend the worst possible deco of all (i.e. the "optional" one).

YOU are the one that brought in RDP. Nowhere did I mention it until you threw out the gratuitous "bend and mend RDP" comment.

It's quite clear that YOUR instructor doesn't agree with the zero SI method, or at least that's what you heard.

There had been a lot of sage advice being given to the original poster. Somehow that led to your wise*** post of

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

My comments were both a reaction to that, and an attempt to get you to see the relationship between the various models and how the are utilized. Clearly, that escapes you.

It kind of like computers. Just because one wears a computer does NOT mean that one must dive bad profiles. That probably escapes you also.

BTW, the last time I looked, my profile didn't say anything about DM or instructor.

I'm glad that you aspire to getting onto a plane with your hair wet. If you do some searches, you can find out what the RGBM guru says about GUE/MHK altitude algorithms and corrections or lack thereof. One can also easily ascertain that the levels of conservatism required by the RGBM model for altitude diving is greater than the classic Cross correction of dissolved gas programs. Perhaps this would lead you to look more closely at the basis behind what you are being taught.

Altitude corrections and fly-after-dive aren't the explicit topic of the original poster, but are related in that they are also GUE taught methods that rely upon a clean ascent with good offgassing. There are, however, basic physical limitations that seem to be being ignored. Luckily, the risk vs. exposure curve in these mild deco situations is a relatively shallow curve (Look at T.D.I.D. to see what I mean) and because DCS is such a low probability, increasing risk by a factor of 10 or even 100 is not likely to be noticed by a person performing such experiments solely upon oneself as opposed to a large sample.

I remember now why I so rarely post in the DIR section.

 

[Ben_ca]

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.

Yes it is very nice to have AG here now in the SF Bay Area I suspect that there will soon be a bloom of X-scooters in the local waters

 

[StSomewhere]

I remember now why I so rarely post in the DIR section.

Because this is what your post eventually distills down to:

You believe that you understand deco or at least you understand one worldview of it, this at times flies in the face of what GUE or JJ or AG or (pick some other DIR instructor) teaches, therefore DIR is wrong and you are right look at all this proof you've gathered, and gawdforbid if you don't rush in to tell the foolish kookaide drinkers they are lemmings marching with their backplates and jetfins and blackskirted masks to their deaths or at least to get horribly bent and goodnessknows you are our scubasavior to prevent these horrible things since we are all so naive.... :roll:

Except not everyone buys your worldview. Why is it so hard for you to realize there is another way?

That's why there's a DIR forum and that's why its "supposed" to be a no trolling zone (Notice: the DIR forum is a No Trolling Zone which is "sticky" at the top of this forum). Things were better before they took down the forum filters, IMO.

BTW, you are the biggest RDP advocate and dive computer defender on SB and you know it, flat wheel and excel RDP calculations and PADI DM Dive Knowledge Workbook and all.

 

[headhunter]

I'd like to offer everyone a few reminders.

Name calling is not acceptable. You can have highly spirited debate as long as it does not cross over into a personal attack.

This is not a venue for agency bashing regardless of which agency we are talking about.

Crossing these lines from this point forward will result in either some serious trimming of this thread or it's removal.

This is not a forum to voice your opinions against DIR. I see this thread as calling for clarification of what is and is not DIR, but railing against the system is not allowed in this forum.

Thanks in advance for keeping things from spinning out of control as we go forward with what appears to be a fairly charged topic.

Christian

 

[TSandM]

There is a nice essay here on the GUE website by Jablonski about decompression experimentation.

To quote from the end of the essay:

It is only fair to conclude this discussion with a note about the nature of decompression experimentation. The long-term effects resulting from hyperbaric exposure are difficult to quantify; even more problematic are the developments of sound decompression practices. Decompression diving (particularly aggressive technical diving) is very much an experiment in progress.

It is very likely that we do not fully appreciate the long-term repercussions of our diving or of our decompression experimentation. Yet, reasonable measures of success include limited painful DCS symptoms, successful Doppler tests, and favorable long bone x-rays, indicating that overt damage is at least limited while drastically reducing decompression time

And to quote another author, David Sawatzky, from an article in the August '05 Diving magazine:

Statistically, you have to dive a given dive profile 400 times with no DCS to be 95 per cent confident the risk of DCS is really less than one percent (600 times for 99 per cent confidence)!

I don't think there is any question that the WKPP has dived some very aggressive profiles and done some very abbreviated decompression by the standards of the most widely used algorithms. To their credit, they have gathered data on themselves doing these dives, using Doppler. But they'll be the first to admit that they are a highly trained, extremely fit population -- and remember that fitness is PART of the DIR approach to diving. And they are also admitting that they are, in effect, using themselves as experimental animals. I think Sawatzky's analysis of the power necessary to generate a valid study shows us that we should be cautious about generalizing the results of the work in the WKPP to the average diving population until a great deal of data have been gathered.