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GUE gear requirements

Discussion in 'DIR' started by MaxE, Apr 19, 2019.

  1. MaxE

    MaxE DIR Practitioner

    1st off I’m not sure this is the right forum for this question but I could not find a sub forum for GUE, mods please move if needed.

    I’m looking into Fundies training sometime in the future. I see that one requirement is a wing without an internal bungee. Can someone shed light on this? What are the drawbacks (from GUE’s perspective) of an internal bungee. What are the positives of the bungee (from manufacturers or designers perspective)?
  2. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    Three kinds of bungee wings
    Bondage wings like those from OMS. Keep the outsides tame, but tend to trap air and if you have the wing inflated to the point that it is pushing on the bungee, if a failure occurs it will squeeze gas out until the bungee is no longer under tension. Not ideal at all.
    Modification on bondage wing like those from Dive Rite. These are more shaping bungees and do not restrict wing lift. Really not needed either, but much more easily removed.
    Elastic bladder covers-not sure who is making them now, but Dive Rite used to with their travel wing and I have two of them. Same argument against them with the bondage wings, but less severe and don't trap gas.

    So the positive is it allows an oversized wing to be less "big" when it's not full. A lot of guys in the 90's and early 00's were using 100lb lift wings from OMS and Dive Rite. No need to ever use them because you should never need that much lift for your rig. If you are picking something up, use a lift bag.
    On the smaller wings, it was to improve streamlining and what not, but again, it largely has to do with using a larger wing than you need or to overcome a bad design.
    Ayisha, rjack321, Ouvea and 2 others like this.
  3. Jack Hammer

    Jack Hammer Solo Diver

    The designers of bungeed wings felt by having bungee compressing the wing it would keep the wing more streamlined at all times. Some concerns are external bungees could snag on things in smaller spaces, would make it it so a minor leak in a wing could squeeze more gas out, the bungees would create pockets inside the wing and make the lift uneven and more difficult to fully vent gas. Most internal bungees had similar issues but not as bad as the external ones. Basically both are considered an unnecessary gear solution to a skills problem.
  4. divad

    divad Solo Diver

    Assuming the bungee is inside the shell/cover and not the bladder, can't it just be removed?
  5. MaxE

    MaxE DIR Practitioner

    Mine certainly can be (Hollis C26 and VDH 18). I was looking for the pros and cons before I remove them. I quickly got a thorough explanation. Thanks @tbone1004 and @Jack Hammer
  6. kensuf

    kensuf Cave Instructor

    Bungees also increase drag, non-bungees have less drag. With water being 800 times denser than air, this can have an impact on your efficiency. Google laminar and turbulant flow.
  7. kierentec

    kierentec Captain

    # of Dives: 5,000 - ∞
    Location: High Springs, FL; Tulum, Mexico
    The biggest issue with bungeed wings is that it pulls the sides of the wing in/down, trapping the gas UNDER the cylinders. This is very unstable. A properly shaped wing allows the gas to sit around the outside of the cylinders, creating a sort of cradle for the heavy tanks and lowering the center of gravity. It seems like a small detail, but its all the small details that make a massive difference, especially with big heavy tanks.
    flymolo, Ayisha, rjack321 and 2 others like this.
  8. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    At the time (1990s-2008ish) the OMS bungie wings were being marketed as a way to solve trim issues. ie you'd leave the bungies on the bottom to force air up to the head and counteract the weight of the valves. They never really worked that way at all. The diverite wings at the time weren't quite as gigantic but their shape was also biased towards the butt and bungies tended to counteract this flawed shape.

    The halcyon doubles wings of the late 90s early 2000s were also horseshoe shaped but 40% smaller than the OMS (55lbs vs 100lbs) and had a more even shape along the sides so there's wasn't so much bias towards the butt. The halcyon wing relied on proper weighting (double 130s aren't even 55lbs of nitrox) to work right and avoided the butt bias of the DRs.

    Basically the bungies were an add-on to a flawed wing that good designs don't need in the first place. With the advent of sidemount this is no longer true and most sidemount wings rely on bungie to some extent. But for doubles wings it just adds drag onto a poor design.
  9. loosenit2

    loosenit2 Solo Diver

    Does anyone have a list of DIR compliant wings? Re VDH wings considered DIR compliant?
  10. MaxE

    MaxE DIR Practitioner

    I’m no expert, but the bungee can be removed from the VDH wings. It’s my (I’m no expert) understanding that’s GUE’s issue so are fine once the bungee is removed, assuming it meets other requirements like suitable lift.
    loosenit2 likes this.

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