: I've heard of people trying "leading edge tape" used
: for aircraft wings
: (http://www.aircraftspruce.com/menus/cs/tape_leadingedge.html)
: but haven't tried it myself.

I have tried it and it is basically a waste of time and money. It's fine for protecting aircraft against sand, but it doesn't stand up to rocks, barnacles and other abrasive surfaces commonly encountered when paddling. The material is too soft (it's designed to absorb tiny impacts) and it gets shredded. It ultimately becomes a ragged, ugly mess.