I am told by someone that had gone through it - once you reside yourself to the fact you are going to drown - it is very peaceful almost serene - very much like diving.
I've heard some similar stories (along with stories of being calm but very sad), but none of the people telling those stories know how they would have felt 30 or 60 seconds later. I've also heard that almost drowning can be very unpleasant. Unfortunately for our inquiries, the people who finish the job are never talk about what is was like.
that is my hypothesis - am I way off?
I don't know enough about deco to offer an authoritative answer, but here's my hypothesis: I'm pretty sure that for ongassing your breathing rate will never be more important than time unless you can hold your breath for a really really long time
*. Either way, you can't ongas very much in a 60 second descent even to 130'. OTOH, if the NDL is only 5 minutes the 60 second descent is a significant portion of your total dive time and the average pressure for the 60 seconds was 3 ATA. Figure 3 "ATA minutes" out of 28 "ATA minutes" (1x3 + 5x5) is just over 10%. Whether returning quickly to the surface, or doing a multi-level dive with a much longer ascent, I don't want to be right up against the NDL when I get to the safety stop, and definitely not when I surface.
Whether by my own calculations or the uncertainty of deco theory, if I'm going to reach my safety stop within a minute or two of the point at which bending becomes likely I've got a strong preference for the point that's a minute or two
before it's likely.
* Even after descending 30' after your last breath, have you ever tried to exhale and there was nothing left to come out? Even the last breath at the surface has more N2 than yu can absorb during the descent; even descending with "empty" lungs means a residual volume that has a fair amount of N2.
So how much N2 is absorbed during a dive and how much does it take to do damage? An AL80 holds almost 2200 liters, so that's a bit over 1700 liters of N2. Just 1/1000 of that N2 is 1.7 liters. Typical adult blood volume is about 5.5 liters, so I'm highly confident that 1.7 liters worth of bubbles is enough for a real whopper of a case of DCS. That tells me that there's no recreational profile that will allow a significant portion (significant relative to the total volume: there's obviously enough for DCS) of the N2 you inhale to actually be absorbed, and that means breathing rate can't be a big factor.
What is the other thread about the effect of breathing rate on on/off gassing?
