[quote] I am concerned because I have read that fiberglass is one of the weaker materials that canoes are made of. I don't plan on white water canoeing, just lakes, rivers and camping trips. [quote]
Weak is a relative term, for lakes and slow rivers almost anything will work and fiberglass is more than up to the job.
I would not recommend any carbon or Kevlar, you could buy a new canoe for just the cost of these products. Stick to simple low cost methods of repair and don't over do it.
Gel coat doesn't typically peel off like that unless there are big problems with how it was done.
Whatever you use on the bottom will get scratched, don't stress over it, cheap paint can be touched up easily.