Hull cleaning

Anyone have issues removing trailer bunk carpet stains from hull? I've got a 2000 Moomba Outback with red sides and while hull. Moomba trailer has black carpet (new) on bunks (also new). Hull has black marks from carpet. I've cleaned entire hull with muriatic acid and water wash. Everything comes clean but the carpet spots. Any suggestions?

Also, boat sits on canopied hoist all summer. Hoist has vinyl covered foam guides which have left marks on red sides of hull. Is paint the only option? If so, where do I find paint? Any suggestions on application method?

It is gelcoat, not paint, so you'll be able to remove any marks with a compound of some sort. Start with a fine cut cleaner and work up to more aggressive compounds if needed. Assuming these spots aren't deep gouges through the gelcoat, your worst case scenario is wetsanding.

Problem in hull at v is through gel coat. I am 2nd owner & believe previous owner had beached boat on sand routinely - wearing away gel. Now, whenever I put in or take out, the v carpeted bow support rubs enough on v to leave the black mark.

Also, I would like to cover a few of the very small, but noticeable, scratches in the red sides. I'm thinking paint is only option. Does anyone have experience with this?

In that case you'd want to look at gelcoat repair, not paint. It can be done yourself but does take some work. Personally I wouldn't be afraid to try the bottom of the hull on my own but would probably look to a pro to handle the visible damage on the sides.