Originally Posted by Avatard
A properly secured and filled Barney bag shouldn't fill with water as water pressing against the outside should in effect displace water contents inside the bag. Unless the bag is open and acting like a sail, It really shouldn't present any more surface area than the contents of the gear inside the bag does.
I agree with the rest of your summation but not the above.
A zipper, that does not have the tabs secured or have locking tab(s), can be opened by pulling on the fabric.
The power of water moving over even a smooth fabric could easily do that.
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I spent twenty years as a Smokejumper and was constantly amazed at the power and ability of air to move things even though it couldn't get under an object. Friction and lift. (We flew with the doors off and had to fix stuff over and over)
Water and air movement are basically the same except water is far more powerful.
I can easily see any weight fabric being moved by water passing across it.
The puckers would be the sail to provide the force to open a non-locking zipper. In that case it could just blow out the zipper but that would have been noticed.
Think about small irregularities in the bags surface being all the sail needed.
Water is just so powerful.
Can anyone look over their Barney Bag and see if it has a locking tab?
One where you have to lift the tab away to get it to move and either open or close.