Where is the HIN on a boat?

Finding the Hull Identification Number takes about ten seconds once you know where to look. Stand at the back of the boat — the transom — and look at the upper starboard corner, that's the right-hand side as you face the boat from behind. The HIN is a 12-character code molded, stamped, or on a riveted plate, usually within a couple of inches of the top edge.

The second, hidden HIN

Since 1984, builders have also been required to place a duplicate HIN in an unexposed location — somewhere not visible from outside the boat. It might be under a fitting, inside a locker, beneath the rubrail, or under the deck. Its whole purpose is to survive a thief grinding off the visible plate, so if the transom HIN and the hidden HIN don't match, you're looking at a re-tagged hull. On older boats (pre-1984) you may only find the one.

How to read the 12 characters

A modern HIN breaks into four parts: the first three characters are the Manufacturer Identifier Code (the builder), the next five are the builder's serial number for that hull, and the last four encode the build date and model year. The letters I, O, and Q are never used, because they're too easy to confuse with 1 and 0. You don't have to memorize the scheme — just decode the HIN free and it'll translate the builder, build date, and model year for you.

““If the visible HIN and the hidden HIN don't match, stop — that's a re-tagged hull.””

Quick steps

1. 01
   Go to the transom

   The flat back of the boat — upper starboard (right) corner.
2. 02
   Read all 12 characters

   No I, O, or Q. Note them exactly, including zeros.
3. 03
   Find the hidden duplicate

   On 1984+ boats, locate the unexposed HIN and confirm it matches.
4. 04
   Match it to the paperwork

   The transom HIN must match the title and registration exactly.
5. 05
   Decode it

   Confirm the builder, build date, and model year in under a minute.