It sounds like the scratches don't effect the integrety of the hull. Your best bet would be to get a gelcoat repair kit from West Marine or Defender. The kits come with small tubes of pigment and if you are careful you can get a good match. Some gelcoats will not dry when exposed to air so get the one that does or get some mold release to paint over the repair to keep the air away from it while it cures. If your careful with the application of the gelcoat a little sanding with some 220 with a block then move down to say 1200 grit, polish with some fine rubbing compound and then wax the boat. Once you get the color right the whole job shouldn't take more than 4 or 5 hours. Good luck, Jack