I like the swirly lines for sure. Not sure about what the sand is bringing to this - I understand that sand and driftwood come together, just that the sand...oh heck, nevermind about the sand. I'm nitpicking. :-) I think what is holding this back for me overall is the lighting. Seems a bit flat. Good luck in the challenge.
*not voting as I'm in this challenge-just commenting since I've seen requests for comments in the challenge thread*
Great subject. It has some wonderfully twisted and curvy lines. I'd love to see a macro of just the 4 or so swirly knots close together there near the bottom right of your photo. Those could make a wonderfully artsy abstract. As is it seems a bit dark or dull and the composition leaves something to be desired. Just needs some jazzing up in my opionion.