Strike:

> I know that, in the past, we've enjoyed a few good debates about reverse
> profiles, and the wisdom of confessing that the most recent dive was
> actually deeper than the preceding one when carrying out multi-dives within
> a 24-hour period on some liveaboards!  :-)))

There's nothing in the math models that would indicate that dive order (deep vs
shallow) matters.
I think with the advent of deriving safe dive time from tissue groups and time
constants,  all those old rules of thumb  went out the door, other than dogmatic
memories.

Other tables epoch lore:

Computer your RNT from the maximum depth, for the total dive time.

I commonly do an hour  wall dive by decending down around 100-120 feet for a few
minutes to see who's home down there, then slowly ascending up the wall.   Perhaps
2/3 the dive is above 35 feet, where much of the good stuff really is.   Sometimes
even no safety stop is  needed, as the last few  minutes were 15 feet anyway.

On tables it would read 120 feet for 1 hour, or in other words, bent,  a brain
aneurysm,  and dead.    On the dive computer, which computes where I really went and
how long I stayed, I'm clean as can be.

>
>
> Like most people, I've always accepted much of what we've been taught about
> diving as being set in granite.

Another pet peeve along that line is the "24 hours to fly" rule.

Me:  "My computer says I can fly in 9 hours, and  desaturated in 14.".
They:   "Yeah but I'm going to wait 24 hours anyway, because it's safer to fly then.

You can't be any safer than totally desaturated.    Otherwise, waiting a fortnight
would be safer yet.   And think how safe waiting a year would be.

When I ran to ground how the 24 hours to fly rule was originally determined, I
learned:  "Well, it used to be 12 hours, but they doubled it."   Wow.   Great
science.



Wade