The completed form will include a description of the watercraft, the purchase price, and both parties' signatures. Considering selling or buying a boat with or without trailer?Take a look at 41 boat bill of sale forms and download a suitable one . If you're purchasing or selling a boat in New York, use a NY Boat Bill of Sale to prove a transfer of ownership has occurred. A boat bill of sale is a document used to record the change of ownership of a watercraft. The seller must complete all applicable information and sign this form. The Bill of Sale or Even-Trade Bill of Sale must be notarized.