I had previously only used this product detailing cars... When my father decided to restore his mid 70s sailboat, this was one of the first products I reached for. After several courses of wet-sanding, we utilized Finesse It with a wool pad and a high speed buffer. The results were amazing. All fine scratches from the sandpaper disappeared and the final result was a gel coat that owners of new boats would be jealous of. Be prepared to use some elbow grease and be patient working the product in evenly. If you do, you'll be very pleased with the results.