The completed form will include a description of the watercraft, the purchase price, and both parties' signatures. 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.Bill of Sale for Boat. A Bill of Sale (BOS) for a boat must have adequate information to positively link the BOS to the boat, similar to the example WRD BOS. To transfer a vehicle from a seller to a buyer in a private sale, you can use the Vehicle Bill of Sale (PDF) (MV-912). Use this form to gather necessary information when you sell your vehicle or vessel. Present proof of ownership (original bill of sale or subsequent bills of sale). Access bill of sale form templates and learn how to transfer ownership of vehicles, boats, firearms, and other high-value personal items in Washington.