My point about diving free gear is this: I know I could dive a lot of things that would make me less negative overall and still give me reasonable air for my recreational dives. I don't want to buy those things. The things I have for free are double steel 120s so I dive them when I dive anywhere I don't fly. I get that ideally I'd be more balanced and probably more comfortable with less tank but my economics just don't allow it.
First you say your gear is free and now your choices are driven by economics.
Cost should never trump function, but I'll point out again that Redundant bladder wings are more expensive, often much more expensive than conventional wings.
I keep hearing there are downsides to the second bladder just sitting there waiting to be used. Tell me what they are. I'm open to hearing it.
No piece of gear is all benefit and without drawbacks. The relative "pros" and "cons" can be debated, but no gear is without drawbacks.
The obvious benefit of a redundant bladder wing is the redundant buoyancy if provides.
The potential negatives include:
Added "clutter"
Added cost
Consider the scenario under which a 2nd bladder would be employed. Our hero diver, who is grossly over weighted, (up to 50 lbs negative according to some "authorities") suffers a total failure of their primary wing. They are plummeting into the abyss.
Now they need to find, and orally inflate their redundant bladder, if they leave the LP hose disconnected. Can a diver
who is grossly over weighted and dropping fast orally inflate quickly enough to solve the problem?
Ok, run the second inflator connected to the 2nd LP hose so our "hero"
who is grossly over weighted and dropping fast can power inflate. One problem solved, but the risks of unrecognized "auto" inflation returns to the mix.
Contrast that with the diver who is Properly weighted, and is never more than slightly more negative than the weight of his backgas. If this diver should suffer a wing failure they simply add a little gas to their suit, problem solved.
Pony bottles and redundant wings lead to the same flawed logic. For ponies it boils down to "I can take risks because I have a pony"
For redundant bladder wings it becomes "I can dive 50 lbs over weighted 'cuss I have an extra wing"
Look at it this way, if the diver is not grossly over weighted, a redundant bladder wing with a stowed, disconnected 2nd inflator presents little risk, OTOH it is not required either, because the properly weighted diver can easily handle a wing failure with their drysuit. If you don't need it don't take it (or buy it)
I have also been involved in a body recovery in which the drysuit was the bouyancy, it failed, and the victim had no gear on at all. Maybe that makes me unusually leery of the drysuit as bouyancy at all. I won't leave the cabin of a boat with a drysuit zipper open. I'll admit I have used the suit as bouyancy plenty of times - but I'm only willing to do so when hardlined to the surface on coms so I can be pulled up immediately if the suit fails. To me that's a recognition of the real limitations of the suit as bouyancy.
Drysuits are not without risk. I've said this before in this thread. The difference is the drysuit is necessary equipment, and the redundant bladder wing is not.
The fact that a drysuit can loose all of it's initial buoyancy in the event of a total failure does not mean that it cannot be used for redundant buoyancy. It does mean that the loss of this buoyancy needs to be considered when sizing the diver's wing.
Tobin