The previous owner had painted over the brown stripes on my CP23 with Sherwin Williams Marine topside enamel. I think they carry it at Lowes in areas near the coasts. There was an old pint can of it left in the boat.
It held up well except where I scratched it several times over the course of a couple of years. When I got the boat ready to sell I bought a new can and painted over it yet again, it held up fine. The prior owners must have painted it several times, I could see the paint was quite thick where I scratched it. I had to put on 3-4 coats to get it to match and fair out.
On my CP27 I scratched the brown stripe a few times. I sanded it out, masked, and used regular rustoleum brown in a spray can to touch up the spots. It matched perfectly, and seems to be holding up well on it's 2nd year.