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>Er..maybe you've met another.
>I've managed to convince myself that I lose up to about 24lbs during a dive
>due to gas usage and start off adjusted accordingly. It seemed to work for
>some reason.
>One reason I'd preferred membrane drysuits was due to the belief that I'd
>have to compensate for a lack of buoyancy at depth.
>This could save me money, as I'm planning to buy a new suit.
24 lbs is conceivable.
The guy I was quoting (not sure it was you) was talking about SEVENTY
pounds.
Dual 104s, filled to 3500, would loose about 19, maybe 20 lbs during the
dive.
I dive dry, and I'm not sure how much a wetsuit would loose when
compressed all the way, but call it 5 or 6 lbs, (with varying mileage),
and we're at 25 or 26- your 24 is easily believable, with dual 104s.
Now.
The deal here is that at the end of the dive, after the weight loss,
you're neutral, so you can do your deco easily.
You're not 14 tons negative, you're not 70 lbs negative, you're not 100
lbs negative. It doesn't change with depth, liquid is not compressible.
With the exception of suit compression, you displace the same amount of
water at 250 feet as you do at the surface, and therefore the amount of
lift necessary to offset the difference between that amount of water
(which remains the same) and the amount you weigh changes only as much as
your weight changes.
You're neutral. Add 5 small pounds of lift to neutral, and you become
truly Upward Bound.
If you're not neutral, (or some prefer, 1 or 2 lbs negative) you're
weighted wrong.
That means at the beginning of the dive, you could be as much as that 25
lbs negative.
THAT'S how much lift you need, at the max. At the beginning of the dive.
Then the lift requirements begin to drop, immediately.
I think that people think they have to start with as much lift as they
have weight on their belt, and then they add in the negative buoyancy of
their tank, their rig, and then they add in a bunch to feel safe. Then
they start saving so they can buy 200 pound bondage wings, so they'll
feel safe.
The package, the weight, you, the rig, is supposed to be NEUTRAL. The
amount of lead required to achieve that state has no bearing on the
amount of lift needed to lift it in the water.
I know of another diver who recently went to fifteen pound wings, because
adding fifteen pounds of lift to a neutral package is a ballistic ascent.
I think he's a lot closer to the true solution for the need than 70 pound
wings.
Of course, I've been wrong, twice. I got married, and I joined the
service. (Unfortunately, both of these are heavily documented- some say
that in itself is a third mistake.) I've corrected both of these errors.
It's conceivable that this could be the third time, but I doubt it.
Referring to my second Mistake, I point out that I've been roasted by
pros, so light your flamethrowers, and have at it.
------------
"C'mon, you sons of bitches, you
want to live forever?"
-First Sergeant Dan Daly, 1918
------------
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