Banded v. Unbanded Wings

[trob09]

I might add one other problem w/ BWOD. If you were to puncture a wing w/ bungees, it will auto-deflate itself. With a non-bungee'd wing, there is nothing assisting the deflation, AND, you may be able to orient yourself so that you can keep some air in the wing.

It's always interesting to play the 'what if' game. What if the bungies retract the wing sufficiently to avoid the puncture? I've seen 2 non-bungied wings punctured because they got pinched between tanks and the wreck. I've not seen a punctured bungied wing.

I personally dive a non-bungied wing.

 

[matt_unique]

To repeat:

Considering the amount of junk hanging on and around your body, the effect of the wing on total hydrodynamic drag is, at most, negligible. We are just not hydrodynamically streamlined.

Cheers!

I dive with a non-bungied wing. I think this argument like so many others relating to drag, hydrostatic instability, etc., etc. are analyzed too much. Specifically in this thread I prefer a non-bungied wing even if only for the puncture argument. If I puncture the left side of the wing I can lean left and have at least some buoyancy in my wing.

Considering the hoses, reels, tanks, arms, head, shoulders, and other non streamlined junk we are pushing through the water the bungy on the wings would not make a bit of difference. Likewise if you are not perfectly weighted or have a little more air in your suit or use ankle weights or etc., etc., etc. Collectively I'm sure all these practices would add up to a *tiny* difference but individually they are negligible.

--Matt

 

[The Kraken]

That's an excellent idea, Sim !!!
I'd like to know the result of that exercise.

 

[DA Aquamaster]

I have dove my Rec wing both with and without the bungees. With doubles, the bungees serve no real purpose other than keeping the wing retracted next to the tank. I have however not noted any difference in drag and as swimmers go, I am on the fast side. I do think however that in a strong current, every little bit helps and I would defininitely consuder using the bungees if I had to hang in strong current.

I have not done a formal leak test exactly as mentioned above, but I have activated the wing mounted dump valve with and without bungees while in a vertical position in the water. There is a substantial difference in rate of deflation with a full wing, but the difference drops quickly as the amount of air in the wing decreases and the bungees will not fully deflate the wing. The several inches of water pressure offset the pressure from the bungees, unless the bungees are way too tight.

In my opinion though, the leak argument is a weak one as you will (should) also have a drysuit and/or a lift bag along so loss of bouyancy due to a very large leak is already addressed. In addition, with a dive rite wing, the bungee is one piece, so you could readily pull the bungee away from the wing, cut it, and easily unlace it under water to elimnate the issue.

Excessively tight bungees are also the only way you can create a situation where you cannot orally inflate the wing. The bungee tension should be properly adjusted with the wing full, and if this is done the effects are moderate and oral inflation is possible. And again, if it's a problem with a DR wing, just cut the bungee.

Which sort of leads to the fact that all bungees are not created equal. The OMS bungees do wrap completely around the aircell and do create the potential for air pockets and entanglements. Dive Rite wings however lace the bungees under the aircell to the edge of the cell through a 4-5 " tube that spreads the load and then back and do not go over the top of the wing. This greatly reduces the potential for air pockets and entanglement.

With a single tank and a u-shaped wing, a set of bungees will help reduce taco effects and will keep the wing from flapping in the breeze so the air trapping issue is pretty much a draw.

In short, I use a non-bungeed wing with doubles as it is not really needed in most circumstances. I will use the bungees with a single tank due to the need to minimize the taco effect. And I will use a bungeed wing when doing commercial work where a single tank bailout is used due to the single tank taco issue and due to the usually low viz/zero viz environment with the potential for pointy objects and a desire to keep the wing close to the tank and out of harm's way.

 

[Dan Gibson]

Only in my early days

To repeat:

Considering the amount of junk hanging on and around your body

 

[DEEPLOU]

No one mentioned that with the bungieed (OMS) you can adjust the bungies to adjust your trim.

 

[Scuba Cowboy]

I have dove both bungeed & unbungeed and I prefer the bungee's. I own an OMS 94 lb wing that works great. None of the reported downsides to these wings have proven true in my case. If possible, dive both before making a choice.

 

[simbrooks]

Didnt get around to doing the little test this weekend - we were finishing up cavern skills and after a couple of hours in the water i didnt feel like getting into that as well.

From what i can understand (from my engineering background) after thinking about this again - is that the bungee in tension applies a passive resistance force (like the ground against your weight through your feet) to the wing and therefore to the air inside the wing that is at the same pressure as the water around it. This resistance in the bands stops the wing from inflating beyond a certain volume (without a failure of some sort), but isnt the cause of the pressure in the wing (water does that for you), just a limiting factor to the size that the wing can inflate to. The air inside will reach a certain pressure and if it cant inflate any further the over-pressure valve will let out whatever air is more than that volume available can take, compared to the water pressure. I still really dont see it as a major issue for the whole system. Its just functioning as another part of the wing itself, would you say that the tensile strength or hoop stress/strain characteristics of the wing material itself provides any kind of incentive to expel air from the wing? I would say it is the same kind of thing.

 

[marcurts]

I use the Dive Rite Trek wing and the cords help to prevent tank wrap (taco effect as DA says)when diving singles. I haven't experience any of the negative effects mentions here so far.

 

[Abratty]

Most of the advantages and disadvantages here have been discussed, but I thought I would mention that I dive Bungies. They are orally inflatable in the water. They do create little pockets of air if you try to completely vent your wing, however, the little amount of air trapped has not been a problem for me, other than the theory of it. The wings are kept in tighter on me which would be an asset when penetrating an overhead environment, and avoiding punctures in the first place. The bungies are closer in the envelope than the wing and therefore in my opinion, not a snag point.

The exhaust does seem to be quicker than non bungied wings though, so not having punctured my wings yet, I would guess that the concern for quicker venting if they were cut would be a problem.

Hope that helps,

Allen

PS I am impressed by the people that can "feel" the drag of the bungies, but then again, there are people that can "feel" the drag of neoprene vs. shell drysuits too...one day I will be that good too