The hull identification number, or HIN, is a boat’s equivalent of a car’s VIN. It is the one number that stays the same when the name, the owner and the registration change.
Where it is on the boat
On boats built for the US market since 1972, the HIN is on the transom, at the upper starboard corner (upper right when you face the stern). It is molded or engraved into the hull, or on a plate fixed there. Many builders also put a second, hidden copy somewhere inside the boat.
If you cannot get to the transom, the HIN is also on the title, the state registration and any documentation papers.
How to read it
Most HINs are 12 characters long, for example SER-V1234-K819:
- The first three letters are the manufacturer identification code (MIC), assigned to the builder.
- The next five characters are the builder’s own serial number for that hull.
- The last four characters give the month and year the hull was built, and the model year.
Why the HIN keeps the records together
Boat names change, owners change, and a logbook kept under an owner’s name leaves when they do. Records tied to the HIN stay with the boat. That is why BoatRealm starts every logbook with the hull number: type it, scan it with your phone camera, or upload a photo, and we read the builder and model year from it.
Buying a used boat? Enter its HIN on Hull Facts to see whether BoatRealm has service records for it.