I'm brand new here but finally someone has asked a question I have a little experience with. Hope I can help. I've done a ton of boats from 20-40 footers and they're really a lot of fun. Very physical though because of the size. First check to see if the boat is gel or has been painted. For gel coat surfaces a rotary buffer with a wool pad is almost mandatory. Get a compound, I've had good luck with the 3-M stuff, and polish the surface to remove minor scratches, oxidation, and stain. Choose a compound that is aggressive enough for the situation but not so harsh that additional polishing will be needed. For a final protectant, Collonite insulator wax does a good job. A PC really helps when applying the wax. If the boat has been painted it's usually Imron or a derivative of that's pretty hard stuff. Use the same products, just be a little more careful. WATCH the decals if there are any. Stay away with the rotary, It'll eat them and ruin them in no time. I have done entire boats with 3-M cleaner wax and it comes out pretty nice. The collonite is just added protection that lasts as long as anything else on the water. I've tried some of my auto products and they do a good job but other that the collonite the expense and volume needed doesn't seem to work for a boat. I think there's a website called properboatcare that will give you a pretty idea of how to do a boat. Unpainted fiberglass is a different animal than clear coated paint.