Fair enough.
So it sounds like you must play around with V-Planner or HLPlanner before every dive to generate contingency ascent schedules in case of going into accidental deco (and not having a working computer?). That's great. The vast majority of recreational divers out there don't do that.
That I never said. The V-planner profile was merely to illustrate that there were reasons to prefer the RD profile to the one you offered, and that disparaging it as untested was not productive.
Because ratio deco is untested, relatively speaking. The strength of any deco algorithm is that others have used it to complete dives safely without a DCS incident.
You're missing the point. Your suggestion is also untested. The Navy table you posted implies that if you've got a deco obligation (planned or unplanned doesn't matter to your tissues), you should be doing stops <30ft in some cases.
Ratio deco appears to be a derivative method that generates ascent schedules that are similar to what other established deco algorithms might offer.
The strength of VPM-B is that people have been logging their dive profiles in a fairly sizeable database.
Are ratio deco users doing the same thing? Hopefully, they are. That would be meeting the empirical test of a "safe" deco algorithm.
I'm not really sure how you are defining "best" when referring to the various algorithms out there.
If you're doing it in your head, chances are you're not using a verifiable model. If you want a tested model, dive your computer's profile, which I suggested is best if available. Neither my random offering of a profile, nor yours, nor the pure RD profile, is tested in the same way that VPM/RGBM are. But if they produce numbers that are close, who cares? This is emergency deco; if the diver with the problem makes it to the surface only slightly bent, that's less than ideal but better than nothing.
I'm not guiding anyone up from depth. I merely made a suggestion on how to conduct an ascent if a recreational diver unintentionally crossed into deco and, for whatever reason, could not follow his computer's instructions on managing the ascent.
But you switched to talking about what you would instruct another person to do. If it's for myself, then complexity of algorithm isn't a problem--which is a fundamental criticism underlying most of your commentary. If it's for someone else, then my above if-then-else scenarios are one way to go about it.
FWIW, your world seems to be far more ordered (wet notes, "conversations" underwater) than what I've witnessed in the average recreational diver.
I'm more than a little surprised that you seem to be advocating to put the diver on higher FO2 mixes to accelerate deco at 20 fsw. How many recreational divers are trained to do that?
Yeah, I'm definitely not advocating higher FO2 mixes for untrained divers, especially panicked ones who've demonstrated poor skills already. Sorry if it looked like I was--it was just a side thought that would work in a very limited context. The average Caribbean boat wouldn't have >40% mixes anyhow.
And yes, my world is more ordered than it used to be. I've worked hard to make it so, and I try to be good about building a community of others who can acquire similar comfort. It's made diving a whole lot more fun.
I think we are in agreement that the diver should follow his computer (if available) and make the best possible use of his remaining gas supply prior to surfacing. In the couple of times that I've seen recreational divers inexplicably surface without fulfilling a deco obligation, the divers had plenty of remaining gas to do an extended shallow stop. Both times the divers admitted not being familiar with the deco mode of their computers. In both cases, the divers surfaced prematurely because other divers were exiting the water -- monkey see, monkey do.
Yeah, that's a shame, and I think we basically agree on this point. I think the point of disagreement comes down to this: If the diver appeared to not be on the verge of panic and if there were sufficient gas supplies, I'd likely slow down the ascent considerably in the top half. This would serve hopefully to calm them down, to help them maintain a controlled ascent (if they can't stop at 40ft why should they be able to stop at 20ft where buoyancy control is harder?), as well as to prevent bubbles from growing.