a boat bill of sale is a legal document that records the sale of a boat between two parties — a seller and a buyer. the boat bill of sale form you need depends on what’s included in the sale, and how your boat is registered or documented. if your boat doesn’t have a title, make sure you have the previous bill of sale or purchase agreement to prove that you’re the owner. you can use the notes section of your boat bill of sale form to mention additional details about the condition of these components.