UTD Decompression profile study results published

[dmaziuk]

So far I know it was made to decelerate your body far more effectively than the seat belt which is barrier #1

That's in the non-free chocolate making countries. Here in Freedom the airbags were invented to decelerate your face somewhat less traumatically than the steering wheel/dashboard/windshield.

According to the Wiki of the Thousand Lies wearing the seatbelt is optional in New Hampshire and not enforced in another 18 states out of 50.

 

[PfcAJ]

It's not. That's the point.

George Irvine, one of the early "fathers" of DIR, used to refer to WKPP divers getting bent somewhat jokingly (this is going back some 20 years now). It is, of course, no laughing matter but the fact that a minor bend seemed (or was presented at the time) as some kind of coming of age within the DIR (or at least the WKPP) community seems odd now with the advent of good computers and the deeper understanding we have of deco theory.

The fact that some tek divers still use ratio deco at all seems as out of place in a modern context as following the "120 rule" that I learned in 1984. Some things just NEED to change as we learn to understand them.

However, as I said above there is a "hardend belief" (a paradigm) within the DIR community that makes it hard for some of the "hard core", especially the elite hard core who have built careers pushing this paradigm, to address issues openly and logically in the context of new technology and new insights. Don't forget that WKPP and DIR in general were early and fanatical adopters of Bruce Wienke's thoughts on deco and they have not let that go despite the overwhelming evidence that Buhlmann gets the job done better.

Hence the blanket statements in the video the OP posted more or less condemning Buhlmann and more or less "prescribing" the outcome of the study.

That's not science. That's religion. ... faith before logic ...

As it is, ratio deco is still part of the training and will probably remain so even though it is demonstrably inefficient and somewhat more risky than learning how to use a modern technical computer. I predict that it will be some time before DIR divers start to question this paradigm from the inside.

And THAT is the current state of affairs surrounding ratio deco.

R..

Sorry you're just incorrect starting with the very first sentence. The entire point of RD as gue teaches it is to end up with the same ascent schedule as your algorithm of choice. You aren't "locked in" to some deep stops thing just because you use RD.

What George Irvine said 20+ years ago is irrelevant.

I'm unaware of any Wkpp divers (and I've been a member of the team for 10 years) who use RGBM or VPM. Everyone's doing buhlmann stuff these days.

 

[PfcAJ]

It works for you and for AG from UTD as well that VPM well work, but since every body have their differences, and scientific studies tells us that there are markers showing that it can be done better, I guess it is reasonable to follow what works for each one or follow the trend of the scientific indications.

You can use RD to come up with a buhlmann style ascent, too.

The whole excercise is about finding trends in your decompression obligations.

If you use a ratio that results in a profile that's identical to 40/85, is that profile somehow now inferior to 40/85 because you got there in a different way?

 

[PfcAJ]

As the practical solution is with any Bubble Model algorithm of which UTD's RD had the history of the longest & deepest deepstops, you're gonna have to extend & pad your O2 deco stops to effectively decompress the surfacing slow tissue tensions if you choose to use RD.

All you've gotta do is adjust your parameters a bit so it mimicks a non-deepstop model.

For instance slow your ascent at 50% instead of 75%.

 

[Kevrumbo]

. . .As it is, ratio deco is still part of the training and will probably remain so even though it is demonstrably inefficient and somewhat more risky than learning how to use a modern technical computer. I predict that it will be some time before DIR divers start to question this paradigm from the inside.

And THAT is the current state of affairs surrounding ratio deco.

R..

All you've gotta do is adjust your parameters a bit so it mimicks a non-deepstop model.

For instance slow your ascent at 50% instead of 75%.

The current state of affairs objectively with regards to Ratio Deco is if you still subscribe to protecting the fast tissues with deepstops, you have to realize that you will put additional surfacing supersaturation stress on the slow tissues and must compensate by extending/padding extra deco time at your shallow Oxygen stops. If this makes RD less efficient, then so be it -whatever it takes to effectively decompress those intermediate/slow tissues especially over the course of several consecutive days of mandatory decompression diving.

That's been the takeaway practical lesson since the NEDU Study was published, and what "DIR" divers have to consider (along with O2/CNS toxicity exposure) if they choose to retain Ratio Deco, or to follow with the new trend of de-emphasizing deepstops along with padding the shallow stops by using Buhlmann GF's like 40/70 or 50/80. . .

 

[Remy B.]

You can use RD to come up with a buhlmann style ascent, too.

The whole excercise is about finding trends in your decompression obligations.

If you use a ratio that results in a profile that's identical to 40/85, is that profile somehow now inferior to 40/85 because you got there in a different way?

So what is the issue to strap on a DC and a slate and follow GF, and leave RD in your mind in case your 1st DC and/or 2nd and your buddy's DC fail and both lose the slates ?

 

[PfcAJ]

So what is the issue to strap on a DC and a slate and follow GF, and leave RD in your mind in case your 1st DC and/or 2nd and your buddy's DC fail and both lose the slates ?

I suppose that's fine until you move to another site where the depth changes. Now your slate is worthless.

With RD I can cook up a plan on the boat in the event of a change.

 

[lowflyer]

When my clinical labs were drawn in 2008 for DCS type 1 with possible DVT/PE, the panel D-dimers and creatine phosphokinase (CPK) levels were elevated. . .

Thanks. These aren't really immune indicators but do suggest you had a potentially bad situation that I'm happy you survived.

 

[Remy B.]

I suppose that's fine until you move to another site where the depth changes. Now your slate is worthless.

With RD I can cook up a plan on the boat in the event of a change.

So you are not diving your plan, and you dive without a contingency plan ?

 

[Diver0001]

Sorry you're just incorrect starting with the very first sentence. The entire point of RD as gue teaches it is to end up with the same ascent schedule as your algorithm of choice. You aren't "locked in" to some deep stops thing just because you use RD.

Maybe I'm wrong. Explain how RD, which as far as I know hasn't changed in the last 15 or 20 years, somehow magically mimics Buhlmann with some kind of gradient factors now when it never has before.

Would you care to explain the process by which the bubble approach has been "let go" and RD now approximates Buhlmann?.... because I'm not seeing it.

I could be wrong about this (and I sincerely hope that I am to be perfectly honest) but I would like to see incontrovertible proof that I am wrong. How do you adjust RD to accommodate "your algorithm of choice"?

R.