How to Look Up Boats Using the Hull Number

Every boat manufactured in or imported to the United States is required to have a unique hull identification number, known as a HIN. You can use an online database, like that operated by the U.S. Coast Guard, to confirm that a boat's HIN is valid and to learn the boat's history.

The HIN is a 12-character number used to identify a boat in the same way a vehicle identification number identifies a car. The hull number is a mix of letters and numbers.

Under federal regulations, you have to display the hull identification code in two different places on the boat hull. The primary HIN must be placed on the starboard outboard side of the transom near the top of the transom. If the boat doesn't have a transom, the first HIN must be attached to the starboard outboard side of the hull, aft, within 1 foot of the stern and close to the top of the hull side. On catamarans and pontoon boats (with hulls that are easily taken out and replaced), the primary HIN code should be attached to the aft crossbeam within 1 foot of the starboard hull attachment.

The second hull identification number must be placed in a protected location on the inside of the boat. It can also be placed under some hardware.

You can learn quite a bit about the boat from the HIN if you know how to decode it. Each group of characters provides different information. There are three groups, the first three characters, the next five characters and the final four characters.

The first group of three characters is the Manufacturers Index Code, or MIC. The next group of five digits represent the boat's serial number that can contain information about the boat length. The final group of four characters gives you the certification year and model number of the boat. Of these, the first character tells you the month (with A being January, B February, and so on), and the next character lets you know the last digit in the year the boat was certified. The final two digits of this give you the model year. For example, if the last group of four characters is A585, it means that the boat was certified in January of 1985 with a model year of 1985.

You may wish to look up the boat's hull number to verify it, or you might want to see its repair history or see whether that model has been recalled. Verification is only necessary with a used boat. If a boat has been stolen, the thief may try to avoid detection by altering the HIN, although it is a federal offense.

You will find several reputable websites that will decode a boat HIN number for free. For example, at hindecoder.com you can type in a HIN to learn if it is a valid number. If not, it will advise you. If it is, it will tell you who manufactured the boat and its model, serial number and certification date. It will also tell you if the model was subject to recalls.

The U.S. Coast Guard also maintains the Port State Information Exchange database. It provides information about boats, including recreational boats, that have sailed in U.S. waters. You can search this database online using HIN numbers.

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