Spisni study

[Dan_P]

@Dan_P Dr Mitchel has asked for your studies that justify RD. You've yet to provide any. Do they even exist? If not, why are you so surprised that many of us lend it the same credence as we do Santa Claus or the Tooth Fairy?

It seems you're still struggling to get your head around the fact that RD is not an algorithm, and I can't fathom why.

What you're asking for, is scientific proof for a Shearwater computer instead of scientific proof for the algorithm plugged into it.
This elaborates on the paradigm:

Again, if you dive a computer with whichever GF-setting you prefer, and I dive RD with whichever deep stop emphasis I prefer, and we both end up on the same deep stop emphasis, would you find that problematic?

I trust you acknowledge the paradox it would be to say that I can't adjust when using RD, while at the same time applying GFs to, say, ZH-L-16 to achieve exactly the same.

If you do, then the question is not about deep stop emphasis - rather, whether one is using a computer or RD.

I don't understand how this is not coming across.

 

[Patoux01]

It seems you're still struggling to get your head around the fact that RD is not an algorithm, and I can't fathom why.

What you're asking for, is scientific proof for a Shearwater computer instead of scientific proof for the algorithm plugged into it.

So what algorithm is "plugged into" UTD RD, since it doesn't follow any conventional schedule?

 

[The Chairman]

It seems you're still struggling to get your head around the fact that RD is not an algorithm,

I certainly understand it's Not an algorithm. As far as I can tell, there is no scientific basis for RD at all which is why there is no study to justify it. None, nada and squat. However, it is still a decompression protocol and as such should be given proper scrutiny and held accountable for the increased numbers of DCS associated with it.

Fudge factors. Let's face it, gradient factors are indeed fudge factors. We have a paradigm, which has been scientifically derived and proven to be safe, and we're trying to make deco even safer with these fudge factors. RD was derived from a hunch that's not based on science but on sheer conjecture and chutzpah. Now you're applying your own fudge factor trying to make RD a bit safer by moving to shallower stops. Kudos for doing that, but why even start with a protocol that's not based in science? It's a faith-based paradigm as opposed to a science-based paradigm like Buhlman.

This is why many of us, including a number of notable scientists, are frustrated with you trying to debunk the science behind GF while completely ignoring the absence of science in RD. If you held RD to the same standard you would not bother with it.

As best as I can tell, RD was born out of a misguided distrust of computers and more chutzpah. There's absolutely no scientific basis for that: only emotional ones.

 

[The Chairman]

You do want to get to the real answer of this Pete?

I do Ross, but I don't think you do or are even close to having one. It's my humble opinion that your obsession with trying to frustrate @Dr Simon Mitchell has clouded your judgment and logic. I've told you this in a PM. At least answer his questions respectfully and try to learn something in the process. I don't want to be negative, so I didn't respond to your earlier statements and would rather continue in that.

 

[rossh]

I do Ross, but I don't think you do or are even close to having one. It's my humble opinion that your obsession with trying to frustrate @Dr Simon Mitchell has clouded your judgment and logic. I've told you this in a PM. At least answer his questions respectfully and try to learn something in the process. I don't want to be negative, so I didn't respond to your earlier statements and would rather continue in that.

Hi Pete,

I don't know if I have the answer either - the intricacies of biophysics is not my forte. But I certainly have been pointing at something substantial, overlooked and unexplained features, within the basic fabric of decompression... more to come too.

Simon has not provided any valuable information to substantiate his insistence that its all deeps stops. In fact, pre-empting some of his answers, we can see he is unlikely to have an explanation.

You call it frustrating a Doctor... and I call getting to the truth of the matter. What's more important? Worshiping your favorite doctor (as your last PM insisted I do), or cutting through the noise and getting to the real issue?

.

 

[The Chairman]

Simon has not provided any valuable information to substantiate his insistence that its all deeps stops.

You've been overstating his 'insistence' for quite some time now. @Dr Simon Mitchell has pointed out again and again, that it's about efficiency and efficacy. When you utilize deep stops, you have to add more time at all subsequent stops to accommodate that decision. In fact, this study shows that doing just that increases the stress markers even with the increased deco obligation. So, no matter why these markers are present, why would you follow a protocol that takes a lot longer to clear and leaves your body in more stress? It just doesn't make sense. Why it leaves you in more stress might be statistically indeterminate at this point, but the study clearly shows that RD with deep stops or traditional air are less effective in doing what we want a protocol to do when compared to GF.

You call it frustrating a Doctor... and I call getting to the truth of the matter

Ross, whether you're doing it intentionally or not, you're not comprehending what @Dr Simon Mitchel is posting. At least you don't appear to and you subsequently twist his words to fit your agenda. Look at your 'insistence' about claiming his 'insistence'. A reasonable person would not continue to mischaracterize his statements in that manner.

If you really want to "get at the truth", then spend the time, get a degree in physiology and do the needed research. We need more researchers and fewer conspiracy theorists. In any event, stop trying to force the data to agree with your understandings. Certainly, most research is based on a hunch, aka theory, but the scientific approach is quick to alter or even abandon theories that don't explain the facts. It's why it's so dadgum hard to pin a scientist down to saying "yes" or "no" about certain aspects of this study. You're trying to box him into a corner while the man is obviously thinking outside the box.

As for Mitchell and Dolette? Oh yes, I am in awe of them and their comprehensive understanding of decompression protocols. I certainly feel honored to have them here on ScubaBoard. I certainly don't understand why you continue to try and fight them rather than work with them for an even deeper understanding. While I am impressed with your coding abilities, I am underwhelmed with your seeming misunderstanding of the protocols you're working with. It's alarming. I would suggest that rather than openly fighting with Dr's Dolette and Mitchell that you try to patch the holes in your understanding that put you at odds with these amazing scientists. Just because you fail to understand a concept doesn't make it untrue, much less a conspiracy or agenda. Conversely, you simply believing in a concept doesn't add to its veracity for the rest of us. They've put in the time and research so the onus is on you to catch up to them, rather than for them to abandon reality in order to agree with your misunderstandings.

BTW, don't forget to answer his questions.

 

[TrimixToo]

You've been overstating his 'insistence' for quite some time now. @Dr Simon Mitchell has pointed out again and again, that it's about efficiency and efficacy. When you utilize deep stops, you have to add more time at all subsequent stops to accommodate that decision. In fact, this study shows that doing just that increases the stress markers even with the increased deco obligation. So, no matter why these markers are present, why would you follow a protocol that takes a lot longer to clear and leaves your body in more stress? It just doesn't make sense. Why it leaves you in more stress might be statistically indeterminate at this point, but the study clearly shows that RD with deep stops or traditional air are less effective in doing what we want a protocol to do when compared to GF.


Ross, whether you're doing it intentionally or not, you're not comprehending what @Dr Simon Mitchel is posting. At least you don't appear to and you subsequently twist his words to fit your agenda. Look at your 'insistence' about claiming his 'insistence'. A reasonable person would not continue to mischaracterize his statements in that manner.

If you really want to "get at the truth", then spend the time, get a degree in physiology and do the needed research. We need more researchers and fewer conspiracy theorists. In any event, stop trying to force the data to agree with your understandings. Certainly, most research is based on a hunch, aka theory, but the scientific approach is quick to alter or even abandon theories that don't explain the facts. It's why it's so dadgum hard to pin a scientist down to saying "yes" or "no" about certain aspects of this study. You're trying to box him into a corner while the man is obviously thinking outside the box.

As for Mitchell and Dolette? Oh yes, I am in awe of them and their comprehensive understanding of decompression protocols. I certainly feel honored to have them here on ScubaBoard. I certainly don't understand why you continue to try and fight them rather than work with them for an even deeper understanding. While I am impressed with your coding abilities, I am underwhelmed with your seeming misunderstanding of the protocols you're working with. It's alarming. I would suggest that rather than openly fighting with Dr's Dolette and Mitchell that you try to patch the holes in your understanding that put you at odds with these amazing scientists. Just because you fail to understand a concept doesn't make it untrue, much less a conspiracy or agenda. Conversely, you simply believing in a concept doesn't add to its veracity for the rest of us. They've put in the time and research so the onus is on you to catch up to them, rather than for them to abandon reality in order to agree with your misunderstandings.

BTW, don't forget to answer his questions.

I was trying to figure out how to write something like this, but (a) you beat me to it and (b) you did a better job at it than I probably would have done.

 

[Dan_P]

So what algorithm is "plugged into" UTD RD, since it doesn't follow any conventional schedule?

Gaming the software with RD2.0 compared to ZH-L-16 with GFs, what do you feel it looks like, roughly?
30/70 or something to that effect?

As for Cascade Deco, it's built around the 30-minute compartment.
There's nothing radical about that.
And it tells the experienced user everything he needs to know about the limitations of it and what to do about it if need be.

However, it is still a decompression protocol and as such should be given proper scrutiny and held accountable for the increased numbers of DCS associated with it.

Personally, I think if you go to 6.000m with any algorithm or solution, and don't adjust for altitude, you'll be poor off.
Shy of that eventuality - which I wouldn't hold against any algorithm or solution itself - actually in either case, I think it's fair to prompt for substantiation to the claim that the DCS incidence is higher when using RD.
It's a very specific and tangible claim.

I know we've been down the road of "risky"/"irresponsible" versus "less optimal" before, so let's not revisit that avenue once again;
I think we've both made our points clear on that, anyway.

I certainly understand it's Not an algorithm. As far as I can tell, there is no scientific basis for RD at all which is why there is no study to justify it. None, nada and squat. However, it is still a decompression protocol and as such should be given proper scrutiny and held accountable for the increased numbers of DCS associated with it.

Fudge factors. Let's face it, gradient factors are indeed fudge factors. We have a paradigm, which has been scientifically derived and proven to be safe, and we're trying to make deco even safer with these fudge factors. RD was derived from a hunch that's not based on science but on sheer conjecture and chutzpah. Now you're applying your own fudge factor trying to make RD a bit safer by moving to shallower stops. Kudos for doing that, but why even start with a protocol that's not based in science? It's a faith-based paradigm as opposed to a science-based paradigm like Buhlman.

This is why many of us, including a number of notable scientists, are frustrated with you trying to debunk the science behind GF while completely ignoring the absence of science in RD. If you held RD to the same standard you would not bother with it.

As best as I can tell, RD was born out of a misguided distrust of computers and more chutzpah. There's absolutely no scientific basis for that: only emotional ones.

Good, okay, we agree it (RD) is not an algorithm and that adaptations are kosher.

Look, let me put it this way, I think you might agree with it:

If I were advocating that RD without adaptations employs the optimal level of deep stop emphasis, I could certainly understand objections!
It probably doesn't, but doesn't claim to either - it's less of a GPS and more of a compass-and-map. It will rarely if ever be more accurate.

Personally, I loathe - loathe - GPS's. That doesn't mean I need to prove that compass-and-map is more accurate. I just need to decide if I like it, or see advantages to it, and whether it's dangerous.
I don't see anything to indicate RD is dangerous, least of all the most commonly referenced trials (NEDU and Spisni). Nothing.

I'll say this to be fair: I do admit that I have some reservations about the NEDU-study, yes, but with Spisni, we can say with some comfort that greater deep stop emphasis than the CDM-group is very likely suboptimal.
It doesn't say where the optimal line is. Nor does NEDU, for that matter.
How much further would/could you place the deep stop emphasis and comfortably claim that you know to be right?
Surely then, in that light, you can understand why an agency doesn't do a 180 without stronger or rather, more accurate evidence, but rather incrementally adjust with the increased knowledge.
Remember, they clearly encourage adaptations, and they don't force anyone to use RD in their courses.

I personally see it as an advantage to have a "standard deco"-paradigm, and I think that's a separate question from what the optimal deep stop emphasis may be. That's neither because of misguided mistrust in computers, personal cultism or narrative.

I simply feel that it's more practical, and a very strong tool for developing situationally aware divers.

I'll reiterate that divers make their adjustments (just like they'd use GFs if using a computer).

 

[Wookie]

Personally, I loathe - loathe - GPS's. That doesn't mean I need to prove that compass-and-map is more accurate.

Out of curiosity, how do you navigate across stretches of water where you can't see shore for days? In the rain? Or is that not a tool you need?

I see this argument as a mental exercise arguing about tools that most folks will never need. I use Ross's software to plan almost every dive deeper than recreational (130 feet NDL) I also monitor real time with my Shearwater using GF set at 30/70. I come to a shallow depth pretty quickly, usually 70 feet on a dive shallower than 300 feet, and switch out to 50% there, and to 80% at 20 feet. But I'm not in any kind of hurry to get on the boat, I'm fairly sure it isn't going anywhere until I get on it.

But the rest of this thread, IMO, is mental masturbation. You won't convince the folks using RD not to, some folks are going to do deep stops, regardless of what anyone says to them, and in all reality, DCS seems to be far more of a "how we all feel that day" kind of issue. Correct me if I'm wrong, but the factors affecting the occurrence of DCS depend far more heavily on how much we had to drink last night, how dehydrated we are, cold stress, heat stress, mental stress, Heart disease, diabetes, and work done than on our Oxygen Clock, whatever that is.

 

[Dan_P]

Out of curiosity, how do you navigate across stretches of water where you can't see shore for days? In the rain? Or is that not a tool you need?

I see this argument as a mental exercise arguing about tools that most folks will never need. I use Ross's software to plan almost every dive deeper than recreational (130 feet NDL) I also monitor real time with my Shearwater using GF set at 30/70. I come to a shallow depth pretty quickly, usually 70 feet on a dive shallower than 300 feet, and switch out to 50% there, and to 80% at 20 feet. But I'm not in any kind of hurry to get on the boat, I'm fairly sure it isn't going anywhere until I get on it.

But the rest of this thread, IMO, is mental masturbation. You won't convince the folks using RD not to, some folks are going to do deep stops, regardless of what anyone says to them, and in all reality, DCS seems to be far more of a "how we all feel that day" kind of issue. Correct me if I'm wrong, but the factors affecting the occurrence of DCS depend far more heavily on how much we had to drink last night, how dehydrated we are, cold stress, heat stress, mental stress, Heart disease, diabetes, and work done than on our Oxygen Clock, whatever that is.

I very much agree with this post.
I'm not here to convince anyone to swap anything they don't want to. And I do think that DCS has more to do with the things you mention, and others, than the differences we're discussing in this thread.
If I'm not mistaken, it was Simon who said the differences here might not be worth arguing over.

Personally, I can't help but think particularly on nutrition/diet in this context, as I think it means a great deal more than minute changes in GF, conservatism settings on a VPM-B or adjustments in RD.

As for the GPS-analogy, fair game, but I did have the GPSs for cars in mind, not maritime applications