A boat serial number, also known as a Hull Identification Number or HIN, is generally found in the upper right corner of the transform when looking at the boat from astern or the back. It is found within the 2 inches below the rub rail and normally within 12 inches of the side of the boat. Locations can vary, however, the serial number should always be on the starboard, or right, side of the transform.
All boats made after 1973 have a serial number as per the U.S. Coast Guard. If you own a boat that was made prior to 1973, it probably does not have a serial number.
Boat serial numbers appear in one of two ways. It can be moulded into the hull of the boat and appear in a narrow rectangular indentation featuring letters and numbers the same color as the boat. It can also be a metal plate held on by two rivets with the serial number stamped or engraved onto the metal plate.
You can identify the serial number as being 12 digits in length and sometimes preceded by two letters and a hyphen which represent the country of origin. These two letters are not part of the serial number in the U.S., but form part of the serial number in the European Union.