A New York Trailer Bill of Sale helps streamline the registration process and proves the transfer of ownership if a dispute arises. Use this free form for private transactions.It comes in a printable PDF format, and you can quickly fill it out using your completer. The Trailer is to be sold free and clear of any liens, encumbrances, or mortgages. For new vessels, the selling dealer must complete the manufacturer's statement of origin (MSO), when applicable.