Proof of ownership on a used boat from a non-title state is the vessel registration. A bill of sale is required with the registration to transfer ownership.Instructions to register a motorized boat in New York State. Use the instructions to complete form MV-82B. Download. The completed form will include a description of the watercraft, the purchase price, and both parties' signatures. The bill of sale must show the purchase price and the amount of out-of-state sales tax paid to the dealer.