MrBlenny
Contributor
@MrBlenny the buoyancy swing is a function of gas volume and has nothing to do with the tank. I.e. 80cf of air has a mass of 6.4lbs, so from full to empty with a pair of them there is a swing of 12.8lbs. That holds true for any other tank that holds 80cf, whether it is an overfilled LP50, or an underfilled LP121. 80cf of air has a swing of 12.8lbs regardless of what it is put in.
Now, an AL80 becomes positively buoyant when empty, but you have to factor that in regardless. With the AL80 you will have more lead on your rig than you would with a steel tank, but the buoyancy shift is a function of gas volume consumed.
I will emphasize that if I could do the dives that I'm doing on AL80's practically, then I would in a heart beat as they make sidemount so easy. All of those videos that you see of bottle handling on youtube are done with AL80's for a reason.....
Thanks, I was thinking of the extra lead that AL require the diver to wear, as opposed to Steel, but didn't properly say so. Nonetheless, given how pro-steel most cold water divers are, it's interesting to hear a sound argument for AL.