I'm not sure that it makes much difference what material you use.
Jake what about on rudder bottoms? glass strands? kevlar? carbon cloth? sheet metal?
Goal being to reduce the loss WHEN you hit bottom (sand or mud around here)
Fibers only prevent a break and high modulus items are pretty useless at the tip of foils unless you really plan on hitting things hard. They won't prevent chips/scrapes/gouges. You need a hard shell to resist that kind of abuse and properly cured gelcoat is hard to beat in this regard.
