I'll second OBG's use of duct tape to prevent blisters.

I know first hand that duct tape seems to stick to wet/sweaty skin better or is more "waterproof" than most first aid tapes.

Had to use 2x2's and duct tape to cover a long gouge I took out of my shin while at work. The first aid tape that I had stuck to my sweaty leg for about 10 seconds. The duct tape stayed for about 6 hours.

It took about 2 weeks for the hair to grow back after I pulled the tape off.