HIN Lookup: Decode a Boat's Hull Identification Number

Decode a boat's HIN

The 12-character Hull Identification Number on the transom names the builder, the serial and the build date: SER12345D404 is a hull built in April 2004 for the 2004 model year.

Builder
Built
Model year
Serial

U.S. Coast Guard recalls by this builder

No recall campaigns on record under this manufacturer code.

How to read a HIN

Three parts, twelve characters

Every boat built or imported for sale in the U.S. since 1972 carries a Hull Identification Number in the format the Coast Guard prescribes (33 CFR 181).

Builder code

Characters 1–3: the Manufacturer Identification Code the Coast Guard assigns each builder. A builder can hold several codes, one per plant or brand.

Serial number

Characters 4–8: the builder's own serial for the hull, letters and digits except I, O and Q.

Build date and model year

Characters 9–12. Since August 1984: a month letter (A is January), the last digit of the build year and the two-digit model year. Earlier HINs use the model-year or straight-year format.

Frequently asked questions

On the starboard (right) side of the transom, within two inches of the top, molded or engraved into the hull. A second, hidden copy is somewhere inside the boat. It also appears on the boat's registration or title.
The first three are the builder's Manufacturer Identification Code (MIC), assigned by the U.S. Coast Guard. The next five are the builder's serial number. The last four give the build month and year and, on boats built since August 1984, the model year.
No. The Coast Guard publishes recall campaigns by builder, with the models and HIN ranges each covers, not the repair status of a hull. Ask the builder or a dealer whether the work was done on yours.
Either a character is mistyped (the letters I, O and Q are never used) or the builder's code is not in the Coast Guard registry, which happens for some very old, foreign or home-built boats.
It lists the recreational boating accidents reported under this HIN from 1995 to 2023, as the Coast Guard released them, and the hull's federal documentation record if it is documented. No record found is not a clean record: only accidents with a death, an injury beyond first aid, $2,000 or more of damage or a complete loss are reported, several states released no records or no HINs, and only about 2% of boats are federally documented. It is not a title, salvage or theft check.
From the U.S. Coast Guard: the Office of Boating Safety's registry of manufacturer identification codes and its boat recall campaigns, the Boating Accident Report Database as released under the Freedom of Information Act (through the Data Liberation Project), and the monthly file of federally documented vessels. All are public records. VehDB adds the boat catalogue makes built under each code.

Related: power boat database, the boats API and the VIN decoder & check for cars.

Need HIN decoding in your app?

The same decode is an API endpoint and an MCP tool, next to the U.S. Coast Guard recalls for every boat in the catalogue.

  • GET /v1/hin/{hin}: builder, build date, model year, the builder's recalls and the hull's reported accidents and documentation record
  • GET /v1/boats/{uuid}/recalls: USCG campaigns for a catalogue boat
  • MCP decode_hin for AI agents
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# Decode a hull identification number
GET /v1/hin/ABC12345D404
# Recalls for a boat in the catalogue
GET /v1/boats/{uuid}/recalls