Son of Deep Stops *or* Waiting to be merged with the mother thread...

[rossh]

Actually, I used to dive a bit with the guys that were implementing VPM style algorithms on a regular basis between 1996 and 2000. The incidence of DCS was pretty high, but we usually just sucked it up and chewed advil (a guy named George used to pop advil starting at 70' like it was going out of style) because of ego and peer pressure.

VPM was not available to the public until August 2001. And then by March 2002 was a hybrid v2. Then in January 2003, VPM-B was the standard.

What ever experimental things were being done earlier, by individuals with self made and unpublished implementations - we don't know.

I don't know anything much about GI's logbook, but I'm sure they are were all big, dangerous and very fast dives ..

 

[rossh]

So let me get this straight. You're claiming that the NEDU held a workshop with decompression researchers (see list below from NEDU TR 11-06). The expressed intent of the workshop was to allow the participants to peer review the study and critique it PRIOR to the actual dive trials. This was meant to be a "speak now or forever hold your peace" event.

After the workshop, B. Wienke posts this ...

View attachment 380508

... where he clearly seemed excited about the live dive trials and described the deep stop profile as "RGBM-like" (see here). His description makes sense because the tested deep stop profile is truly RGBM-like and VPM-like (see here).

So your position is that sometime after Wienke and the other researchers attended the workshop where all the participants were briefed, the NEDU simply changed the profile and tested something entirely different? That's your position???? Really?????

Isn't it much more likely that the NEDU just did the test they told the peer review group they'd do? And the results were very inconvenient for some people who had a financial interest in a certain outcome? Doesn't that seem like a more credible explanation to you? It does to me.

What on earth are your trying distort now...

2004 - planning.
2006 - testing
2008 - publish report #1 - UHMS workshop
2011 - publish report #2


The nedu finally tested two shallow stop navy design models. What ever they discussed and promised in 2004, would seem to have been adjusted. You could take it for granted that Bruce, with his fingers in RGBM, is not going to get excited about a pair of shallow stop nedu test models.

.

 

[rossh]

I was waiting for the "L" card to be dealt.

Ross, since I am obviously looking for patterns in your work, the phrase "reverse engineering" clearly applies. You have a right to protect your intellectual property. Are you OK with me messing? This sort of thing would normally be done with a mutual non-disclosure agreement signed by both parties and blessed by both sets of lawyers. Such is pointless here. This is SB, if you can't yap about it then it is not worth the effort to tease anything out. No prob either way.

But at the moment, I'm completely fascinated by the possibility of smoothing out the experimentally based Navy Air Table 5 for the purpose of better modeling. (simpler equations)

Please continue, all. This is most interesting...

Yes agreed - its your thread - lets go with that.

But we need to define some terms and objectives.

What is the "required" level of deco? Does a model represent that?
How much margin has been added to each model, and can it be removed to come to a common base line?

A great deal of a models margin for safety is the hands of the designer, and how he feel or chooses to implement that. How are you going to account and equalize that?


Difficult to do.....

How do you propose to compare shallow and deep? There is no tool to do this with so far. The dive procedure is where the DCS injury starts. Clearly the differences with in-dive stress levels are significant. If the compare method does not give value to that aspect, then it becomes just another one side biased to the shallow attack.

What about different run times for the same dive? I hope we not assuming that all dives are somehow, magically made equal by using the same end run times?

If it were the navy, it would be a pDCS measure, but they only have data on their own kind of shallow stop based dives - no deep(er) stop data there.


************


Right now, all we have in the 40/70 crowd saying..."look, my plan is longer and slower than yours, and as a consequence of that it less risk than yours" . to which the answer is ... so what - we know that already.


..

 

[rjack321]

What is the "required' level of deco? Does a model represent that?
How much margin has been added to each model, and can it be removed to come to a common base line?
..

"Required" is at least as much deco to keep your DCS rate low enough that a human subjects review board won't terminate your study!!!

Apparently having one profile with 5% DCS and another with 1.6% DCS for the exact same total deco time isn't adequate for you to conclude that a 1.6% DCS profile is better. 5% was statistically greater than 1.6% despite having far far fewer dives than Wienke thought they would need to demonstrate differences.

I will go back to my bowl of bubbling jello. This continuation thread with 1,000 minutes of air deco is a continued beating of a dead horse.

 

[rossh]

"Required" is at least as much deco to keep your DCS rate low enough that a human subjects review board won't terminate your study!!!

Apparently having one profile with 5% DCS and another with 1.6% DCS for the exact same total deco time isn't adequate for you to conclude that a 1.6% DCS profile is better. 5% was statistically greater than 1.6% despite having far far fewer dives than Wienke thought they would need to demonstrate differences.

I will go back to my bowl of bubbling jello. This continuation thread with 1,000 minutes of air deco is a continued beating of a dead horse.

You want to argue about the nedu test again? You keep loosing every time.

*********


Repeat after me... The nedu study did not test deep stops.

They tested two kinds of shallow stops, the differences of which are already fully addressed in every kind of dive computer, and deco planning tool.



But take a look at this. Why did they quit the shallow stop test half way?? Answer: Because it was about to fail its rejection criteria test, and invalidate the whole effort:

Where is A1 headed ? Out the bottom, suggesting that the test model settings (derived from the massive navy database) were not properly calibrated to the test sequence...

added: What was the predictions before the test sequence, per pDCS?

These predictions are 3/4 ths wrong too.

The BVM(3) - a nedu creation that does not exist in usage, or represent anything in tech diving arena, prediction is grossly wrong. Good ! No body wants to use BVM(3) anyway.

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[rjack321]

Ross I don't care what you have to say. I saw how little deco VPM+5 called for in the nedu expsoures. I've seen all your criticisms of Simon and Kevin. The "fake" VPM+7 that was the only way to get enough deco time from VPMb/e. I've seen you claim everything under the sun about the nedu shallow stops being too long or too cold. And now you use words like "losing" to try and invalidate the recorded DCS rates - the only known measurements of their kind. Is that what this is all about to you? "Winning" an argument? Serious question, what is your end game? What's your ideal outcome here? And on the long since closed RBW thread, and everywhere else you have belabored this topic ad nauseum. You want me or Simon or Kevin or someone to validate you and say "you win"?

 

[rossh]

Ross I don't care what you have to say. I saw how little deco VPM+5 called for in the nedu expsoures. I've seen all your criticisms of Simon and Kevin. The "fake" VPM+7 that was the only way to get enough deco time from VPMb/e. I've seen you claim everything under the sun about the nedu shallow stops being too long or too cold. And now you use words like "losing" to try and invalidate the recorded DCS rates - the only known measurements of their kind. Is that what this is all about to you? "Winning" an argument? Serious question, what is your end game? What's your ideal outcome here? And on the long since closed RBW thread, and everywhere else you have belabored this topic ad nauseum. You want me or Simon or Kevin or someone to validate you and say "you win"?

The nedu exposures are 2x normal required deco.... NO model makes that much unneccessary deco like the nedu test profiles.

If you think VPM is too short then, that means EVERY model is also too short. So take a REAL HARD LOOK below. Real models all finish in the 90 to 120 min region. The nedu test was double that time at 214 mins. The Nedu divers got injured from the cold (deliberate extra thermal stress) not the profile time.

Then maybe you could come back and retract all the invalid statements above.

 

[cerich]

They all got injured by cold eh? What does your software recommend for cold exposures Ross? Since the NEDU had double the times....and they got injured.

 

[victorzamora]

The nedu exposures are 2x normal required deco.... NO model makes that much unneccessary deco like the nedu test profiles.

Ross, you keep using this term with absolutely no basis to say so. The two NEDU profiles had high DCS rates. Your chosen model has deeper stops and far less shallow stops than either of the NEDU profiles.....yet you think it would have reduced DCS rates?

The conclusion of the entire study was that taking your deco obligation and putting more of it shallower is safer, the only questions are "how much of it?" and "how shallow?" but you're proposing deeper and shorter stops would help reduce DCS under those same conditions?

 

[rossh]

Ross, you keep using this term with absolutely no basis to say so. The two NEDU profiles had high DCS rates. Your chosen model has deeper stops and far less shallow stops than either of the NEDU profiles.....yet you think it would have reduced DCS rates?

The conclusion of the entire study was that taking your deco obligation and putting more of it shallower is safer, the only questions are "how much of it?" and "how shallow?" but you're proposing deeper and shorter stops would help reduce DCS under those same conditions?

I wonder if you really seem to understand the nedu test conditions? They designed the test procedure - low profile stress, high thermal stress.

The time was double what any plan calls for or needs - including the USN dive manual for the same dive. The stops are all shallow - and one had its stops offset further by an average of 10 ft - all still shallow. No deeps stops anywhere to be found or seen.

That on its own was not enough to cause injury, and in fact both plans has very low Supersaturation (profile stress) values. The values are far less than any dive that anyone does today. Then they made the divers cold and mild exercise - almost 4 hours naked, in water that eventually had them shivering. Thermal stress did the damage. That is where the DCS comes from.


So to your question - There is plenty of basis to be stating the nedu test was far too long by ordinary deco standards. Every deco model has less than half the deco time of the test..

Also it shows that thermal stress can ruin any kind of otherwise safe dive : see this: TR 2007 06

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