Single vs Double Bladder Wings - Pro's and Con's ?

[eelnoraa]

Just looked it up in the Hollis manual - it is 85 lbs each, so yes an insane amount - P

• BAC D85 – Double Tank Dual Bladder System85 lbs (38.6) Lift Each – removable bungee included
  

What other said. The lift of the wing is largely controlled by the side of outter shell. Bladder are usually slightly bigger than the shell, so the shell is getting stress when fully inflated, not the bladder. So with a double bladder wing, the same thing apply. Although each bladder can be inflated to fully fill the shell, but at any instance, it is the sum of two bladder = 85lb. Both can't be fully inflated because of outter shell.

I think the issue with this wing is two fold: dual bladder + 85lb. 85lb lift is just way to big. If the wing is 40-45lb dual bladder, I will probably try to remove one bladder, remove inflator hose and dump value, put cover over the holes, and use it as single bladder wing.

 

[Phil_C]

Thanks for the responses, about confirms what I remembered from previous posts - dual bladders are seen as a bit of a gimmick and not really necessary, and 85 lift way too much. For the moment I will stick with the DIRZone wing and maybe try the dual bladder out someday just for the experiment. It's really not much of a loss, it cost about the same as buying a replacement inflator hose so I've got one extra spare inflator for free.

Thanks - P

 

[diversteve]

Can you fit a transom and ~5hp outboard?

No but he likely can raise the outboard if he finds one..

Zeagle sells a big dual 85# wing like that also:

One of our largest bladders, the Big Bertha is a dual redundant bladder assembly consisting of two independent 85 lb urethane bladders inside of a single Cordura nylon cover. Each bladder has its own airway and a single bottom dump valve that operate independently of each other. The bladder cover is a durable Cordura nylon material with an expandable elastic nylon insert on the front of the bladder to retract the bladder. - See more at: Zeagle Big Bertha

 

[doctormike]

I got one as well, very cheap ... hmmm, wonder why these are so cheap?

I only used it on the occasion that I was diving double steel 100s in a fairly thin wetsuit, which doesn't happen very often. I also have other redundant buoyancy (SMB and Lift Bag), so maybe it's not really necessary, although a backup bladder would be easier to deploy in the very rare case of a bladder failure or significant inflator leak.

I never would hook up a second inflator hose, if I had to use it I would just inflate it manually. Less hoses, less chance of accidental inflation, certainly not necessary for such a rare mode of failure.

 

[bakodiver391]

Give the wing to me, I'll give it a good home. In reading the article about the South African woman's death, it seems she was doing far too advanced dives for someone with only 200 career dives. Plus having the inflator hose attached on the backup wing is something I would never do. We just had an incident where a guy had the corrugated hose come completely off the elbow on his single bladder wing. He tried to employ his lift bag as redundant buoyancy and the dump valve didn't dump. Only quick action by his buddy prevented him from rocketing to the surface. He's buying a dual bladder wing.

 

[Nasser]

This phobia with dual bladder wings on SB is absolutely ludicrous.

If used properly they are a viable and hassle free way to achieve redundant buoyancy when diving wet... and this does not preclude diving a balanced rig, which should be incorporated by all divers (sport and tech divers alike) even if redundancy is not required. I dive a 55 LB dual bladder wing and have the hose unclipped but bungied to the corrugated hose and my right shoulder harness webbing. In the event of a failure, I simply reach over and clip it on... simple and quick, no ridiculous lift bag decos needed. Like anything else, knowing your rig well and practicing how to use it in an emergency is the key.

Diving a balanced rig and having the dual bladder gives me the pleasure of proper weighting as well as the additional safety and peace of mind that extra redundancy provides.

 

[Peter69_56]

This phobia with dual bladder wings on SB is absolutely ludicrous.

If used properly they are a viable and hassle free way to achieve redundant buoyancy when diving wet... and this does not preclude diving a balanced rig, which should be incorporated by all divers (sport and tech divers alike) even if redundancy is not required. I dive a 55 LB dual bladder wing and have the hose unclipped but bungied to the corrugated hose and my right shoulder harness webbing. In the event of a failure, I simply reach over and clip it on... simple and quick, no ridiculous lift bag decos needed. Like anything else, knowing your rig well and practicing how to use it in an emergency is the key.

Diving a balanced rig and having the dual bladder gives me the pleasure of proper weighting as well as the additional safety and peace of mind that extra redundancy provides.

Totally agree with you. I dive a dual bladder Hollis 45 lb as well. Its more important when diving 3 mm wetsuit or less with twins, deco tanks, torches etc so a significant weight load with no additional lift from a wetsuit.

We can all die if we stuff up. Doesn't have to be a dual bladder. I never use anything but my left inflator. Right one is unclipped and not used unless an emergency. Should I need it I have it, and much more control with it than a SMB as an emergency device (although I have practiced with using them as well). If you are going deep, in particular with significant amounts of tanks and gear, a dual bladder gives more redundancy than risk. If you are diving a single tank, 30m, no deco, well that's a different matter as the risks are less and if you have to use an SMB to come up and don't get it right, then the risks of DCS is far less. Get it wrong with a 100m 10 min bottom time dive and that's a different outcome.

Its horses for courses. The right gear for the job. Off the top of my head we have recreational diving, solo diving, tech diving, cave diving. Each requires different setups and gear to give best performance. Because one diver has died, do we then throw away all the dual bladders? I think not.

 

[DogDiver]

When diving a dual bladder system either side mount or back mount. You do not attach the redundant inflator prior to or during the dive. The LP inflator hose is only attached if needed with a primary bladder failure. With my dual bladder Nomad, the primary inflater hose can be removed and attached to the backup inflater. As with any side-mount cave setup, I also have a secured inflater hose on the other cylinder. I dive wet, and after a punctured bladder at Hart Springs a few years ago, it wasn't fun exiting without buoyancy. I purchased the dual bladder system. [emoji41]


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[kensuf]

The autoinflating is certainly an issue. I have seen people use a regulator hose with a shutoff then a QD adapter on them before, but that is the catch 22. You either have the issue with auto inflating confusion if both are plugged in, or you add failure points with two adapters before the wing to prevent it, or you have it disconnected when it may not be feasible to reconnect it especially in cold water with gloves. Simple solution, dive a balanced rig with a single bladder wing

My first bc didn't have one of those power inflator thingies and I lived to tell the tales of diving it. Even in cold water you should be able to orally inflate, and if you're in super cold water you're probably rocking a drysuit, so why use the double bladder?

 

[doctormike]

...if you're in super cold water you're probably rocking a drysuit, so why use the double bladder?

Doubles and a wetsuit. That's the most common application. Not so common in cold water/dry suit dives....



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