I also showed that the difference in bubble growth in that sample was 21%. "Is that a little burp"? If I am wrong, where is my error?
Or will you follow the lead of my UTD instructor when I used that same math to show the difference in volume that occurs when you change depth at altitude as opposed to changing depth at sea level? He said the equation I used made no sense. I told him that if it made no sense, he should publish a paper explaining why it made no sense, because anyone who can show that, after hundreds of years of being accepted, Boyle's Law is wrong would become instantly famous. He didn't reply to that, but a conversation years later (following a fatal accident while diving at altitude) showed me that he still did not accept that math as valid.
We're talking about gas expansion during ascend and it's impact on bouyancy control here, I presume.
That's what I referred to with the "burp"-remark previously, in either case.
Say you're at the most extreme stop in terms of relative pressure differential, the transition from 6m to 3m.
I think that's a fair setting.
At sea level, the gas expansion across 6m and 3m would look like this:
1,6-1,3 = 0,3 bar
(0,3/1,6)x100 = 18,7%
At 2000m, like this:
1,4-1,1 = 0,3 bar
(0,3/1,4)x100 = 21,4%
The difference:
21,4-18,7 = 2,7%
While I expect the total amount of gas in the wing at 6m would be the same, I expect it would grow by 2,7% more across the ascend from 6m to 3m on the altitude dive, compared to sea level.
Now, at this point in the dive, we'll have nearly nothing in our wing. Let's say 1L for measure.
The difference is 2,7cl.
That's literally less than a burp.
If you want to talk about some scenario where you go all the way from depth to the surface, and then show that there's a larger difference, then no - that makes zero sense. You'd be screwed no matter where you dive in that case.
In either case, I'll say that anyone who can't control their bouyancy on an altitude dive, can write it down to lack of skill rather than physics.
Buhlmann's entire body of work is the reference because his tables were based in part on experimentation done at altitude, but there is much more than that.
Any reference will do, John.
The principal counterargument equivalent to your statement, would be "everything AG ever said"
You're the one taking digs for a lack of evidence, which I acknowledge. I say there's no evidence answering you what the "perfect" approach is.
But, if you really think it's that black and white, let me ask you this:
Do you or do you not apply gradient factors?
I'm not saying altitude has no impact on physiological decompression. I'm saying you, I, John, even Buhlmann in the reference above, don't know the in's and out's of it all.
To say that RD doesn't prove scientifically how the puzzle is laid out, is ridiculous as nothing else has either.
Unfortunately, Buhlmann doesn't answer our questions here, either.
I have said that the way I see it, an inreased relative pressure differential per unit of ascend, would increase bubble mechanics impact on the physiological decompression during ascend (though of course not exclusively).
I don't think that's a reason to resort to the below on that basis:
Altitude doesn’t matter. There’s no evidence.
And if there is, then it’s not convincing.
And if it is, it doesn’t matter much.
And if it does, then it’s not RD’s fault.
And if it was, there must have been another factor.
Besides, I'm not the one going on about lack of scientific evidence.
John's initial post about exactly that, is pretty much the reason I responded to him in the first place.
Finally, you might care to know that I am confidently diving altitude dives believing that the increased emphasis on deep stops incorporated in RD, matches reasonably well my view of decompression during altitude diving, coupled with added time to the shallow stops, for reasons we've discussed extensively previously.
Contrary to the apparent narrative of scuba's figurative internet brigade, Ratio Deco isn't a cultist religious symbol any more than a hammer is to a carpenter.
Could I sit down with a piece of software and plan my dive every time, like I was trained to initially? Sure. I just don't think it's practical.
Do I acknowledge that while I think Ratio Deco is much more practical, it probably isn't
perfect in terms of decompression? Absolutely.
Show me what
perfect looks like, and I
might opt for that - if it's reasonably
practical.
And as for the bouyancy thing, I honestly think that's full-on ridiculous.
