If you replaced your Hobie 17 composite fiberglass tip with a carbon comptip, it would negate the purpose of the comptip, which is to keep people from getting electrocuted if their mast contacts an overhead powerline. Carbon, as I understand it, is an excellent conductor of electricity.

If you put a carbon tip on your mast, it would not be class legal. So if you are not going to race in class and are going to race in open class or not going to race at all, why not just get a whole new mast, designed properly for the boat?

Seems silly to have a two-part mast if you don't have to.