The age of a boat can be determined by its Hull ID Number, or HIN. Documents provided with the boat, if a new purchase, also contain the year of manufacture.
A hull number consists of three parts: the manufacturer's ID code, a personal serial consisting of five numbers or letters, and a certification or build date. The manufacturer's ID code contains three letters specific to the importer or assigned by U.S. authorities. The serial number can be a string of five numbers and letters, except I, O and Q. The last part is the important part that determines the age of a boat -- it references the month and year the boat was manufactured.
According to U.S. government regulations, Hull ID numbers must be linked to every boat made or imported in the United States. These numbers must be permanently fixed to the hull with an additional copy located inside the boat. Even if a boat is manufactured for personal use, a hull number must be created.