If you want the versatility, quick aim, and ability to dunk the camera for underwater footage, a hat cam is pretty useful. It's cheap and easy to make, especially in your timeframe with your upcoming trip. I wasn't a fan of the headstrap mount. I just stuck the mount on the bill of cap, and then epoxy'd the edges so it doesn't fall off. I put it as far back on the bill as possible for stability and so it doesn't feel all wobbly on my head. I've made pole mounts, and those are ok too, but in the end.. more often I just grab this cap and GO~~!!
Here's my hat-cam.
Here's a video taken with my hat-cam. 0:30-1:55 has some underwater footage, including an underwater CP&R! (or is it CV&R??)
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"There he stands, draped in more equipment than a telephone lineman, trying to outwit an organism with a brain no bigger than a breadcrumb, and getting licked in the process." –Paul O’Neil