Federal regulations require that every boat built in the United States must be identified by a unique 12-digit Hull Identification Number (HIN). The HIN rules were written to enable manufacturers to identify boats in the event of a defect recall.
The Coast Guard assigns each commercial boat builder a three-letter identification code. The HIN was introduced in 1972 and was standardized on August 1, 1984 as follows:
The three-letter boat builder ID code
Boat serial number
The month of certification or manufacture
The year of certification or manufacture
Boat's model year (For the boating industry, the new model year starts in August.)
Builders in about 70 countries, including
some in the United States, have adopted manufacturing standards developed
by the International Organization for Standardization (ISO). The ISO
Hull Identifier Number has a format that is identical to the 12-digit
system used in the United States. However, since foreign boats have
a manufacturer identification code assigned by their country of origin,
there has been some confusion between the two HIN versions.