What is the purpose of a bungeed bladder

[rfwoodvt]

Just beginning my Explorations into BPW setups. I seen reference to bungee cords on bladders and haven't quite figured out what their specific purposes.

Any enlightenment would be appreciated.

 

[The Chairman]

Were these 'bondage' wings popular in the past due to the weight of torch batteries

It was a pendulum swing... that was the "more is better" mindset that was an offshoot of the dept of redundancy dept, dept. What if you found an object so heavy that you needed the lift? It was a problem that didn't really exist. But, they had to control those floppy wings somehow, so they wrapped them in bungees. FWIW, I could easily orally inflate mine and holes were no more problematic than a normal wing. The bungees weren't so tight you couldn't get enough air in them to dive safely.

Then we took minimalism to a new depth, where we calculated the amount of lift needed to the ounce. People were bragging about how small their wing was like they were getting away with something. There are two deaths I attribute to this fad. Well, not enough lift certainly contributed to their demise. In any event, all the cool kids were diving with 16# and 18# wings because they were cool enough to pull it off.

So how do you have a sane amount of lift without looking like a giant undersea taco? Bungees are a great answer. Public opinion is against having them around the wing, so they're used sparingly on the underside to prevent "tacoitis".

FWIW, my most stable single tank set up was the OMS bungeed 100# wing, with a spreader plate. That was a piece of aluminum that was about two inches smaller than a backplate. It went on top of the wing and spread it out to prevent the dreaded taco effect. There simply was no air shift when you changed attitude in the water. It drew ire mostly because it was homemade, but it worked well since it was my only wing/bcd. Now I have a set-up for most every type of diving. Backmounted doubles, backmounted singles, Rebreather, side mount heavy, side mount light, and so forth. It's hard to keep up with it all. Sometimes I jump in the spring with no bladder. It's how I first learned to dive and it's fun. Yeah, I draw some criticism from a few instructors as they think I'm setting a bad example by being trim and neutral without a bladder. But hey... no bungees!

 

[kierentec]

One of the major issues with bungeed wings is that the bungee is designed to hold the air cell down under the tanks.

Having a tank(s) on your back is generally unstable. The heavy stuff on top, floaty stuff (diver) underneath creates a unstable platform that constantly wants to roll over and “turtle”. A properly shaped wing should taco up around the tank(s) about 3/4 of the way up. This puts lift higher on the tanks, creating a cradle for the heavy cylinders to be supported by. A bungee system eliminates that, as does using a small wing on larger tanks.

For example, A 40lb wing is generally well suited for double 7.25” tanks (AL80s, lp85s, etc) and a 60lb wing is good for 8” tanks (104s). It’s not just about lift capacity, using a 40lb wing on 104s might be enough lift to keep you on the surface, but the wing won’t taco around the tanks enough for proper stability.

 

[Eric Sedletzky]

Bungeed wings were something that was invented for big doubles wings before BP/W became popular for single tank diving. It was something that seemed like a good idea at the time and for some it was. GUE/DIR was a very vocal opponent to bungeed wings because as TBone said you can’t orally inflate against them at least that was the talk whether it was really true or not. I think some of the vocal protest from the DIR crowd was also about Halcyon wanting more market share. The whole thing was semi politicized, you’re gonna die, we don’t allow bungeed wings on our charters, blah blah blah.
Anyway, since BP/W became more popular for single tank diving companies like Oxycheq excelled at wing designs and came up with the Mach V narrow wing. Everybody copied them because of how streamlined they were. You don’t see many if any bungeed wings around anymore. The only single tank wing I know that has an internal bungee is the VDH wing but it is a single piece of thin bungee cord that runs inside a piping loop inside the wing along the outer perimeter.
It actually works very well but can easily be removed too if wanted.

 

[The Chairman]

A properly shaped wing should taco up around the tank(s) about 3/4 of the way up.

Oh sure, put function ahead of style!

Of course, the inherent instability of backmount is why sidemount has become so popular.

 

[The Chairman]

As a caveat, with a backmount single, I dive a very balanced system, which means I rarely put air in my bladder. I find that the absence of any buoyancy or weight shift increases my agility as well as safety. I rarely dive with exposure protection, so this works well for me.

 

[Wibble]

Having a tank(s) on your back is generally unstable. The heavy stuff on top, floaty stuff (diver) underneath creates a unstable platform that constantly wants to roll over and “turtle”.

Thankfully we now use rebreathers that are considerably lighter without the massive keel weight of steel cylinders — GUE JJ excepted.

Wing only has to balance the weight of the bailout gas which is in the relatively light ali80s. Plus a bit extra for a bag of scallops/lobsters.

 

[johndiver999]

Just beginning my Explorations into BPW setups. I seen reference to bungee cords on bladders and haven't quite figured out what their specific purposes.

Any enlightenment would be appreciated.

I just bought this wing, no bungies, seems good for single tank diving.

It looks to be well made and the price is very competitive. They offer free shipping and a free inflator hose which some other vendors charge for, plus I think it is wide enough for fat, LP tanks. Hopefully I will be happy, I have not heard much about this option on this forum that I recall.

Buy Trianta 2.0 Wing - 30lbs of Lift - DRIS

Buy Trianta 2.0 Wing - 30lbs of Lift at DRIS for the best price. The DRIS Gear Trianta 2.0 wing is a clean and compact circular bladder design.

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[VikingDives]

My issue with bungees isn't oral inflation, but what happens when you get a failure in the wing. Say your dump valve breaks or falls off while you're diving. If you have a bungee, some, or most of the air is going to be forced out of the wing. Sans bungee, you can use body position and displacement to keep some air in the wing for an ascent...

 

[The Chairman]

If you have a bungee, some, or most of the air is going to be forced out of the wing.

That depends on how you dive. I ripped a hole in my OMS on a wreck, and while I noticed I had to add air from time to time, it took a buddy telling me I had a leak for me to realize it. Amazingly, somehow, I just didn't die or even come close.

Just as there are many solutions to imagined problems, there are also imagined catastrophes to every feature. I had been sold on a Oceanic Probe backinflate BC, so I gave my OMS away with a single tube patch away. Shortly after that Tobin sent me one of his first BP & wings to test dive.

 

[Eric Sedletzky]

There’s also the issue of an entanglement hazard with bungees. The cords can get caught on things sticking out like metal parts on wrecks, etc. The less cords and clutter to get caught on something the better.