UTD VBlog: Complex Ratio Deco Questions · UTD Scuba Diving
Check out the slide behind him. Look at the 300ft oxygen time setpoint.
Ok, but where does the slide claim to reduce shallow stop time by adding deep stops when not using O2? The presumption by
@Diver0001 was that RD adds deep stops to shorten the stops in the shallows which simply isn't true.
People have responded to you on a number of occasions, pointing out the issues, but you either ignore them completely or respond with statements that indicate that you are not on top of the theory.
Can you please point out where I have ignored anyone? Whether you think I am on top of theory or not is a matter of opinion. I think more accurately, when I respond with statements that seem contradictory with yours and others, you conclude that I'm not "on top of theory."
I was about to respond to [some of your statements, but the list got long. I quite.
So you chose not to respond. Got it.
If you read the threads on the deep stop study and understood anything about the scientific process, then you would understand why that is not an issue. For those who did not understand, the issue was explained ad nauseum in the thread.
I want to get this straight: you believe that one can draw the same conclusions regarding deep stops for an Oxygen-based decompression dive from a study which used air for decompression? A study which is vaguely related to actual deep stop diving as
@rossh pointed out? You think that is a scientific method? If Peter likes Mary, and Mary likes Paul, then Peter must like Paul then too?
Actually, you said at some points that UTD does have something to say about it somewhere.
Where exactly?
You said your instructor said that if you dive at altitude, you can't use RD without adjusting it. Another poster said a UTD instructor told him the same thing. So something is being taught.
If I ask you how you might do a dive in Truk Lagoon, does that count as PADI officially teaching me how to do a dive in Truk Lagoon? I asked my instructor personally what he might do. Don't confuse that with the agency having any official training on how to dive at altitude.
So, for the 10th time now, UTD does not officially teach altitude diving. If you ask any instructor about it, they will tell you the same thing.
Debunked aspects of RD:
The first stops are too deep.
Too deep for a Buhlmann model? Sure. What part of RD deep stops are "debunked?" Where's the science that disproves it? If RD used air only for decompression, based on a vaguely related NEDU deep stop study, I might agree with you more. Where's the sciences that says a dive involving oxygen-based decompression and deep stops is bad?
The S-curve provides no benefit
Please point me to the research that disproves S-Curves have no benefit and is "debunked."
It is not so much that the science "debunked" it
You're contradicting yourself. You said it was "debunked." Now it's not?
It does not spend enough time in the shallow stops. This is especially problematic considering that the deep stops study said that if a diver spends more time doing deep stops, the the diver needs to spend even more time in the shallow stops to compensate. RD spends MORE time in the deep stops and LESS time in the shallow stops.
I would agree with that study, if we were using air only for decompression. The deep stop study also used air for decompression. RD uses oxygen-based decompression like any sensible diver would.
It cannot be used at altitude, so it leaves the altitude diver with no established way to do such a dive.
Why couldn't it be used at altitude? I've posted a few altitude profiles as well as Kevin, but you conveniently ignored those posts. I'll ask again, do you think those profiles are acceptable to execute at the altitudes they were derived for?
When I started tech diving, I read extensively through a lot of material because I did not feel comfortable with what I was being taught. It was TDI, but the instructor was dedicated to GUE. He had taken GUE courses from AG, and his TDI instructor trainer was and still is an employee of the owner of GUE.
When UTD was created, the TDI instructor crossed over to the new agency, and all his students had to cross over with him. There were immediate conflicts, because what I was reading in the course materials conflicted with what I had been reading previously. I contacted Gene Hobbes of Rubicon repeatedly, and he steered me to a number of studies on decompression. Gene and I had some interesting chats about the results.
Those conflicts continued, and I had a special problem with the study that was the basis for the S-curve, which I believed had a totally unfounded conclusion that violated gas laws. I was also concerned greatly about the belief that altitude did not matter, which has been well documented in this thread. Again, Gene and I consulted.
I crossed back to TDI, and I read a lot of other articles as I began to adjust to life using VPM.
Then began the deep stops debates on Rebreather World and on ScubaBoard. Holy Smokes! Reading through all of that made my head spin. You can read through all of that if you like to get an idea, but you won't get the whole picture as far as I am concerned. Throughout much of the Deep Stops debate on ScubaBoard, I had an extremely intense ongoing email discussion with Ross Hemingway, one of the key antagonists in the debate. When I say "intense," you can assume it was not always a pleasant exchange.
For a while on a dive trip I roomed near one of the foremost authorities on decompression in the world, a man who consults on decompression issues with NASA and the Pentagon. I learned a lot.
All of that over a decade brings me to where I am. I can't estimate the number of articles I have read during that time, and I can't estimate the number of people with whom I have talked. The one thing I can say for certain is that I know there are people whose understanding of all of this is so far beyond me that I am in awe of them. I can't touch their knowledge or understanding. So where am I? All of it leads me to plan my dives the way I describe here. It is what I think right now is what is best. But my mind is open. If some new Earth-shattering research is released tomorrow, I will pay it all due heed. I will not cling to past beliefs because of past beliefs. As Emerson said, "A foolish consistency is the hobgoblin of little minds."
So what you are asking me is to got through the last decade or so of my research, track down all the articles I have read, and provide an annotated bibliography. The theory is that this will change people's minds. It won't. Other research shows that when people become entrenched in a belief and are presented with solid contradictory evidence, they become even more thoroughly entrenched in their original belief. It would take me hundreds of hours to do what you ask, and it will not change a single mind.
Eight paragraphs to basically say you don't know exactly where you got the research from, it's just in your head. So we should trust you just because of that? That's no better than this:
During that webinar, one of the participants asked how he knew RD was correct, and he said, "You have to have faith." "Faith in you?" she asked. "Yes," he answered.
Do we really have to rehash all this again? Youre not expert, Ross, in anything except making software. Yet here you are pretending to know more than the experts at NEDU.
I don't think he was claiming to more than the experts at NEDU, but that the deep stop study is vaguely related to actual VPM-based diving. He doesn't have to be an expert to point that out. If a smoker tells you you shouldn't smoke, does it make him wrong?
. Might as well stop funding NEDU, and you should try to find a new job, because those tables are all we need and ever needed. Sorry folks, fun's over, decompression is solved. 
