vehicle and vessel licenses and registrations
Both federal agencies like the U.S. Coast Guard and state agencies such as the California Department of Motor Vehicles have databases of registered ships and boats.
The National Transportation Safety Board also tracks accidents involving marine vessels.
Some of the federal databases are online.
The U.S. Coast Guard has a database of marine vessels that are registered with it or with which it has had contact. Vessels weighing 5 tons or more must register with the Coast Guard (such vessels are referred to as being "documented"). Go to:
You can search by the name or number of a vessel to get its dimensions, tonnage, and other documentation. The database does not include ownership information.
For information on shipwrecks and other major maritime accidents, try the National Transportation Safety Board's:
Sail boats longer than 8 feet and any motor boat not documented with the U.S. Coast Guard must register with the California Department of Motor Vehicles.
However, the DMV does not have a website where you can access any of this information, and there are severe restrictions on what information you can request (such as restrictions on the home address of anyone who has registered a boat).
Here's the DMV page describing their boat registration program: