If i am making a bill of sale for a boat what if i dont know who the boat was previously registered to?

-how can the person i am selling the boat to register it?If you are making a bill of sale than the owner of boat might be yourself.But if you don't know who is the owner of the boat than you can check the title of the boat with the state concerned boat authority who has the record of registration.



If you are not the owner you can not sale your boat because it is illegal.
Isn't it registered to you, the current owner?