I'm not certain what type of boat you have, but I've added Kevlar skid plates to canoes before. I prefer the "S-Glass" material rather than the kevlar felt. The felt is thick and heavy (we're only talking oz here, but why add extra weight and drag?). A layer of S-Glass and you'll never wear through.
If you have a royalex boat you have many epoxy options. If you have a poly boat, West Systems has many options that will adhere. I really like West Systems' G-Flex epoxy. I've gone through a lot over the years.
If you do have a royalex hull & wear through the vinyl indo the ABS (light green color) you can always buy some Legos, melt them down in acetone to match you hull and paint the liquid on. Lego's are made of the same material that the outside of your hull is. If you're good and take your time you match it nearly perfect and be good for another decade of paddling with out the added effort or cost that comes with adding Kevlar skid plates.