Questions about Dual bladder wings

[PfcAJ]

The tanks will be lighter than that because of helium.

the dual bladder thing with steels is cute until you're mid-water. You can't get the inflater out and hook it up/orally inflate fast enough. With al80s, you swim a little (and not much, at that) and with a drysuit, you press a button. No games no gimmicks.

Also, you weight your rig for its lightest with just empty backgas. Stages can be ditched (up the line or to a buddy). No sense in carrying extra weight.

 

[Abdullah]

The tanks will be lighter than that because of helium.

the dual bladder thing with steels is cute until you're mid-water. You can't get the inflater out and hook it up/orally inflate fast enough. With al80s, you swim a little (and not much, at that) and with a drysuit, you press a button. No games no gimmicks.

Also, you weight your rig for its lightest with just empty backgas. Stages can be ditched (up the line or to a buddy). No sense in carrying extra weight.

You make a few false assumptions.

First, the OP isn't diving a dry suit. Neither am I: Water is too warm, even with a tri-lam suit. I'm diving a 3mm wetsuit year round, and feel hot in the shallow stops. The risk of thermal injury from the dry suit is higher than the risks from equipment failures. SAC rates are also higher when you're overheated.

Second, you're not going to descend very much inflating the redundant bladder. I'd be swimming a bit whichever system I was diving. There's nothing cute about it, just reach back, grab it, and orally inflate. I use my buddies for visual reference in the water column. A little practice and it's not even inconvenient. No harder than shutting down a valve.

The dry suit is your gimmick, the dual bladder mine. Dry suits fail for many of the same reasons a wing fails. Except the wing doesn't burp gas through seals.

Helium makes steel a little lighter too. You're still hauling lead, and I'm not bringing any.

Folks are trying pretty hard to make the standard model fit for everybody. But, there is a valid niche for dual bladder technology. And the niche is large enough to inspire multiple manufacturers to think they can produce them profitibly.

 

[ucfdiver]

You make a few false assumptions.

First, the OP isn't diving a dry suit. Neither am I: Water is too warm, even with a tri-lam suit. I'm diving a 3mm wetsuit year round, and feel hot in the shallow stops. The risk of thermal injury from the dry suit is higher than the risks from equipment failures. SAC rates are also higher when you're overheated.

Second, you're not going to descend very much inflating the redundant bladder. I'd be swimming a bit whichever system I was diving. There's nothing cute about it, just reach back, grab it, and orally inflate. I use my buddies for visual reference in the water column. A little practice and it's not even inconvenient. No harder than shutting down a valve.

The dry suit is your gimmick, the dual bladder mine. Dry suits fail for many of the same reasons a wing fails. Except the wing doesn't burp gas through seals.

Helium makes steel a little lighter too. You're still hauling lead, and I'm not bringing any.

Folks are trying pretty hard to make the standard model fit for everybody. But, there is a valid niche for dual bladder technology. And the niche is large enough to inspire multiple manufacturers to think they can produce them profitibly.

Have you ever known of a dry suit to leak so badly it cannot sustain buoyancy? I've NEVER heard of such a thing, not even 3rd hand.

 

[dumpsterDiver]

Have you ever known of a dry suit to leak so badly it cannot sustain buoyancy? I've NEVER heard of such a thing, not even 3rd hand.

I've been diving a long time and spent a lot of time diving on charter boats etc. so I have witnessed a lot of diving too. I have NEVER experienced or witnessed anyone puncturing a BC so bad that it would not hold some air. I have seen many, many instances where BC's have screwed up, OP valves pop off or fail, also inflator hoses rip/tear, inflator mechs auto-inflate etc...

So the primary failure mode for a BC is mechanical failure, rather than catastrophic damage/puncure.... What are the possibilities that BOTH bladders will be punctured catastophically? Is it more or less likely that an inflator hose or inflator valve on a dry suit will fail..or the OP valve on the dry suit for that matter?

 

[ucfdiver]

I've been diving a long time and spent a lot of time diving on charter boats etc. so I have witnessed a lot of diving too. I have NEVER experienced or witnessed anyone puncturing a BC so bad that it would not hold some air. I have seen many, many instances where BC's have screwed up, OP valves pop off or fail, also inflator hoses rip/tear, inflator mechs auto-inflate etc...

So the primary failure mode for a BC is mechanical failure, rather than catastrophic damage/puncure.... What are the possibilities that BOTH bladders will be punctured catastophically? Is it more or less likely that an inflator hose or inflator valve on a dry suit will fail..or the OP valve on the dry suit for that matter?

All wing failures I've seen have been dump valves (I've had that happen) and the hose pop off the inflation side. My only argument against dual bladder wings are if you keep both plugged in, you can't tell what side is free flowing if it happens, and if you don't, when you lose buoyancy on one side, you don't have time to plug the other in.

 

[dumpsterDiver]

All wing failures I've seen have been dump valves (I've had that happen) and the hose pop off the inflation side. My only argument against dual bladder wings are if you keep both plugged in, you can't tell what side is free flowing if it happens, and if you don't, when you lose buoyancy on one side, you don't have time to plug the other in.

You assume the diver will plummet to the depths instantly if an OP valve fails? Before oral inflation can occur? If your only objection is this issue and the concern over an auto-inflate situation, then why not install an in-line inflator hose shut off valve?

 

[ucfdiver]

You assume the diver will plummet to the depths instantly if an OP valve fails?

Depends on what the diver is carrying. Frankly i don't think LP85's with a wetsuit is as serious as some of the people in this thread do. I've dove that combo myself. My comments were more directed at large doubles.

If your only objection is this issue and the concern over an auto-inflate situation, then why not install an in-line inflator hose shut off valve?

I'm not sure that throwing even more gear at the real issue (being over weighted) is the correct answer.

 

[dumpsterDiver]

Depends on what the diver is carrying. Frankly i don't think LP85's with a wetsuit is as serious as some of the people in this thread do. I've dove that combo myself. My comments were more directed at large doubles.


I'm not sure that throwing even more gear at the real issue (being over weighted) is the correct answer.

I thought you said the only problem you had with the idea was the inflation issue? A valve will address THAT issue. Now if you want to go back to simplicity... maybe oral inflation is not so bad, then?

 

[danvolker]

In my early days of diving, when they began "pushing" the wearing of a BC on us( which I and many others hated and fought), they were all oral inflate ( most with emergency CO2 as well). Oral was easy enough back then, because mostly it was only a breath or two you would be adding...pretty much anyone ought to be able to manage that, even quickly if needed. But back in those days, the tanks we were balancing were steel 72's, the most perfectly balanced tank of all time...and we had a wetsuit and weightbelt combo that was pretty close--in other words, there was nobody in the 70's diving with the weight of 4 heavy steels, other than commercial hard hat divers. So there was no one back in the day, trying to blow 60 pounds worth of inflation, or 100 pounds worth, into a huge wing. We would blow in maybe 5 pounds....Ten if it was to stay on the surface like a boat

The old days of oral inflation just don't support oral inflation of the monster wing, when it needs to support a high lifting load. You really would want this to be done with your regulator and an inflation mechanism.

I have to agree also, that I have never seen a punctured wing. I have heard about it in rare cave diving scenarios--which is one reason the Halcyon system was built to be so tough.... I supposed a diver pulling them self through tight shipwreck penetrations might have this as a concern also--but I would not want to be doing that with 4 tanks attached to me either

To be fair in the discussion of the dual bladder wings, I have been negative mostly due to my easily imagining the dual bladder monster wing pairing with the heavy steel tanks and wetsuits--diver with negative weight at bottom of dive exceeding 60 pounds. This may be a ridiculous caricature , but in fact, we have seen this often, and this is why I am arguing against.

 

[dumpsterDiver]

I'm not sure a punctured dry suit can provide 100 lbs of lift either. Wearing ridiculously heavy steel tanks clearly generates some significant vulnerabilities, but could someone choose to dive a "moderately" negative rig and use a double bladder wing? I think that is more along the lines of the OP's question.