Hull Identification Numbers (HINs) were not required until November 1972. Prior to that, boat builders used serial numbers, but these had no standardized format or clear indication of the boat's manufacturing date.
In 1972, a standard was implemented requiring HINs to include the date of manufacture. The format was updated again in August 1984 to enhance clarity and standardization.
The National Association of State Boating Law Administrators, in cooperation with the U.S. Coast Guard’s Boating Safety Division, created a document titled:
U.S. Coast Guard Hull Identification Number (HIN) Validation & Verification Guidelines.
You can access this document here
Key Insights from the Guidelines
The Two HIN Formats (1972–1984)
Between November 1972 and August 1984, boat manufacturers used one of two formats for HINs:
- Straight Year Format
This format focused on the manufacturer, serial number, and exact production date.
Example HIN: BOA135791273J
- BOA: Manufacturer Identification Code (MIC).
- 13579: Serial number assigned by the manufacturer.
- 12: Production year (last two digits of 1973).
- J: Month of production (J = October).
- Model Year Format
This format included a code to identify the model year rather than the exact production year.
Example HIN: BOA13579M84E
- BOA: Manufacturer Identification Code (MIC).
- 13579: Serial number assigned by the manufacturer.
- M: Indicates the use of the Model Year Format.
- 84: Model year (1984).
- E: Certification month (E = December).
The presence of the M in the HIN was the key indicator of the Model Year Format.
The Second HIN Format Change (Post-August 1984)
The HIN format underwent a significant change in August 1984.
Example HIN: BOA13579B607
- BOA: Manufacturer Identification Code (MIC).
- The MIC identifies the manufacturer and is assigned by the U.S. Coast Guard. MICs can be reassigned if a manufacturer has been inactive for 10 years.
- For instance, "CBC," previously assigned to Chrysler Boat Corporation, is now used by Coastal Custom Boats.
- 13579: Serial number assigned by the manufacturer.
- Letters I, O, and Q are avoided to prevent confusion with numbers.
- B: Certification month.
- The letters don’t correspond to the first letters of months (e.g., A = January, L = December, B = February).
- 6: Last digit of the year of manufacture or certification (e.g., 1986).
- 07: Model year or year the boat was offered for sale (e.g., 2007).
State-Issued HINs
If a boat lacks an HIN or has an incorrectly formatted one, states can issue a new HIN. For example, Chrysler Buccaneers may have received updated HINs if their original HINs did not match current formats or if their MIC, "CBC," was reassigned to Coastal Custom Boats.
Summary
The evolution of HIN formats, particularly the changes in 1972 and 1984, explains much of the confusion surrounding older boats. It also highlights why some Manufacturer Identification Codes, like Chrysler’s "CBC," no longer correspond to their original designation.
For further details, explore the U.S. Coast Guard HIN Validation & Verification Guidelines in our document library..