- Decode the hull identification number20 min
Every boat built after November 1, 1972 carries a 12-character Hull Identification Number (HIN). This step decodes each character group to confirm that the manufacturer, model year, and serial number match the seller's description.
A tampered or mismatched HIN is the strongest indicator of a stolen or salvaged boat. The same HIN feeds the lien check, the survey contract, and every registration application.
Find the HIN. It is almost always on the starboard (right) side of the transom, about 2 inches below the deck line.
On outboard-powered boats it may be on a metal plate or sticker near the engine bracket; on sailboats check the starboard aft quarter near the waterline. Take a clear close-up photo.
Decode the MIC (characters 1–3). The first three characters are the Manufacturer Identification Code. Look it up on the USCG MIC Database to confirm the builder exists and matches the brand name.
Decode the serial (characters 4–8). The builder's serial number for that model year. No cross-reference is needed — just note it.
Decode the date (characters 9–12). Characters 9–10 encode the month and year of certification using a letter-number pair (e.g., “H2” = August 2002). Character 11 is the last digit of the model year; character 12 is the exact model year. The two can differ when the boat was built late in one year for release as the next model year.
Verify online. Enter the full HIN at the USCG HIN Decoder and confirm the returned model year matches the seller's listing.
Record it. Write down the full 12-character HIN, the decoded manufacturer name, and the confirmed model year. The lien check, the survey contract, the sea-trial notes, the bill of sale, and the registration form all draw from this number.