You're picking some good topcis here. Makes a guy want to tune in everyday, even with the risks around here.
It's not so much how deep you go, but how fast you asend, if I understand this area correctly. A diver is going to absorb some extra N2 at any depth, and more at greater depths, but - the solution from any recreational depth is to offgass the disolved gas slowly enough to not form bubbles in the blood.
I ascent at 1 foot every 2 seconds to 50 feet where I stop for 1 minute. I then continue at the same rate to 40 feet where I stop for 1 minute. I then ascend more slowly, 1 foot every 3 seconds, to 30 feet where I stop for 3 minutes. I then ascend at the same rate to 15 feet where I stop for 5 or more minutes.
Wow - that's impressive. Sounds excessive to me, but maybe I should consider it more. From what I've seen of Walter, he's probably seriously doing it, not just talking it.
You are absolutely correct. Most divers pop immediately to the surface from their 15 ft safety stop. It should be a time to slow the ascent. A slow acscent from 15 ft requires better buoyancy control which may be part of the problem.
Horrible practice!! There's a greater relative change in pressure in the top 15 feet than any other 15 foot segment of the water column.
1 ft/2 seconds to 50. Stop for one minute then ascend to 20' (same ascent rate) for one more minute. Then 3 min at 10'.
Not as careful as the more extrmeme example above above, but this plan is more likely to be followed by someone looking here to learn. Still very conservative, as well as worth the time & effort.
What I do is not quite so conservative, but somewhat similar: 1ft/sec to 60 ft, 1 ft/2 sec above 60 - with a 1 minute stop at 1/2 max, or 50 feet in this study, then a 1 minute stop at 1/4 max, or 25 feet here, then easing up to 10 ft over the next 3-5 minutes. Air consumption is so much slower in the shallows, so why not?
My preferred ascent rate is easy to do on a mooring line, but more challenging on a free ascent. This is the same ascent rate required of my newest computer, so if I can keep it quiet, it's accomplished, albeit a rare occurance for me.
I have also noticed that once someone earns a manditory deco obligation of say 1-3 minutes that they typically clear that manditory deco obligation but then fail to add the extra safety margin of another 3-5 minutes which they would have done or should have done had they stayed within no decompression limits.
Boy - Not Me!! My computers are no more conservative than PADI tables, even though a little different, so when they require anything, I give them that much plus some, always. If either of them demands 3 minutes, I give them at least that much plus the 3 minutes I'd give them if they demanded nothing.
BTW: "Lassie" was played by many different dogs over the years, with a few different ones used on each segment for different behaviors, but - they were all played by males. The Freudian suggestions of a boy and his female dog were the marketing theme, but the females were too difficult to work with.
