Perdix CEIL, does it take into account the estimated off-gassing on ascent (with an assumed ascent rate)?

[dmaziuk]

That was at 30/75 -- it works to illustrate the problem, but IRL I wouldn't be using 30/75 (if I had a ZH-L16 computer) for no-stop dives.

For a more realistic no-stop setting in the 90/90 ballpark, you'd probably have to add another 10 metres or more to the depth, to get the same effect. That's gonna push you past 40 msw, among other things.

There's probably plenty of "AOW" wrecks where these "transient ceilings" could be an issue, but with those I'd say: join BSAC and get properly trained for those type of dives so you don't need to care much about them. And if you plan your dive for staged deco, your ZH-L computer and its GrapeFruits will work as intended, too.

 

[Rogerdd]

My take is the point of this thread is whether CEIL assumes an ascent. IMO, it doesn't, so it's on the diver to manage this grey area you're describing. (I agree with everything you've said, BTW.)

The initial question was whether CEIL assumed an ascent or not.
My guess was that it does NOT, and the purpose of this thread was to get a confirmation.

After some discussion, the question became wider and now it’s not just about CEIL but also NDL: does it assume an ascent rate or is it an ‘instantaneous’ ascent?

If CEIL is instantaneous but NDL is not, then we can have a ceiling without stops.

I believe it’s important to first agree on whether both CEIL and NDL are assuming an ascent or not, because that will impact whether the statement above is true or not.