H2Andy:ok... this came up in another post, but not to hijack
-- assuming your BC or wing fails at depth and you can't fix it (huge hole)
-- assuming you ditch your weights
how much negative buoyancy left over can you overcome to get to the surface?
five pounds?
ten pounds?
fifteen pounds?
I usually have my dry suit as a redundant buoyancy system, but assuming the BC failed and the drysuit failed, then I could always blow some gas into my sausage, but assuming that failed too, and I was too tired or lazy or unable to swim myself up, I could always pull an Uncle Pug and hitch a ride on my buddies back.
Recently when I was in Coz, I tested this out a bit. I'd brought my steel BP, and even with no weight I was negative (not sure by how much). So on a shallow solo dive (25') I dumped my air to see if I could swim the rig up. I wasn't negative by much, so it was pretty easy. But if you were more than a few pounds heavy, the challenge might be, I would think, staying up on the surface for any length of time.