You will need the title, registration and any relevant Coast Guard documentation for your boat. Also, make sure you have title and registration documentation for any associated trailers. A bill of sale is typically used to document the transaction and includes things such as hull or vessel identification number, description of the boat, purchase price and transaction date. If a licensed broker is involved, there is typically additional paperwork that serves to protect the buyers and sellers involved in the transaction. Other paperwork you should have includes insurance documentation, maintenance and service records and any warranty information.