To find the previous owner of a documented vessel, request a USCG Abstract of Title. This will include not just the owner of a vessel but the entire chain of ownership of the vessel. You will have access to the names of the previous owners as well as the status of any liens/mortgages recorded against the vessel.
You can search the USCG documented vessel database by Hull Identification Number (HIN) or official number.
That search reveals the vessel’s particulars/dimension, Service Information, certifications, documents, (such as the status of its current Certificate of Documentation), and more. It will not show you the vessel’s owner nor their address, as access to that information was removed in 2018.