Since November 1, 1972, all boats must have a 12-character hull identification number (HIN). These numbers are required by federal law and help the manufacturer identify the owners of their boats in case of recall or a defect notification. A change was made August 1, 1984, mostly regarding placement of the number. Due to the danger of vandalism or other damage, one number is now required to be hidden from view. Reading the HIN on your boat is a straightforward process, once the code is understood.
Examine the first three characters. These consist of the manufacturer's identification code, which is issued by the Coast Guard to each boat maker. You can search their database of boat manufacturers (see Resources).
Look at the next five numbers. These comprise the hull serial number, which is issued by the manufacturer.
Examine the last four characters. These indicate the date the boat was built. This includes the month and year, with the month assigned an alphabetical code, such as "C" for March.
Homemade boats also need an HIN. Your state boating agency will issue one, with the first three characters being the state abbreviation, followed by "Z."