A boat’s hull number (HIN / CIN): reading it, checking it, photographing it

The hull number is to a boat what the serial number is to a car: the unique identifier engraved by the builder, which links the physical boat to its papers. It is called the HIN (Hull Identification Number) or, in European regulations, the CIN (Craft Identification Number). Reading it, checking it and photographing it takes five minutes; it is one of the simplest and most important checks before buying, and one of the items of the sale file.

1. Where to find it

On boats that comply with European regulations (placed on the market since 1998), the number is permanently marked — engraved, moulded or on a riveted plate — at the stern, on the starboard side, on the transom or the aft part of the hull, near the top. A second, identical mark is placed in a hidden spot inside the boat, precisely so that any tampering with the visible mark can be detected. On older boats, the number may be elsewhere (mast step, cockpit, under a bathing ladder) or may not exist; the builder’s serial number then appears on a plate or in the manual.

The CE certificate of conformity and the owner’s manual carry the same number. The builder’s plate is separate: it shows the builder, the design category (A, B, C or D), the maximum load and the number of people, but not necessarily the hull number.

2. How to read it

The European format has 14 characters, often written with a hyphen after the first two. For example FR-ABC12345C707:

• FR — the builder’s country (two letters).
• ABC — the builder code (three characters), assigned by the authorities of its country.
• 12345 — the boat’s own serial number (five characters, digits or letters).
• C — the month of manufacture, a letter from A (January) to L (December); here March.
• 7 — the last digit of the year of manufacture; here 2007 (or 2017: the model year removes the ambiguity).
• 07 — the model year (two digits), here 2007.

This format is set by the European directive on recreational craft (Directive 2013/53/EU, Annex I, point 2.1), which takes over the format of the previous 1994 directive. Boats imported from the United States carry a 12-character HIN, with no country code, whose last four characters give the month and year of manufacture and then the model year. Two practical lessons: the year of manufacture can be read from the number, so you can compare it with the year stated by the seller (a “2008 model” built in September 2007 is normal; “2010” on a 2006 number is not); and the serial number allows the builder to trace the boat’s history, its original options and sometimes recalls.

3. Why check it before buying

The hull number must be identical on the hull, on the registration document (the French certificat d’enregistrement, or the former carte de circulation or acte de francisation), on the CE certificate of conformity and on the original invoice. It is what proves that the boat in front of you is indeed the one whose papers you are being shown.

• A number that is missing, sanded off, painted over, covered with a sticker or with a character that looks altered is a major warning sign: a stolen boat, a boat written off and rebuilt, or the papers of another boat. Do not buy without a verifiable explanation.
• A number that differs from the papers by one character may simply be a typing error at registration — but the seller must have it corrected before the sale, otherwise the change of ownership procedure will be blocked.
• A year of manufacture that does not match the year stated changes the value of the boat and possibly the version of the model.
• Two marks (visible and hidden) that do not match: same conclusion as for an altered number.

The number is also used by the authorities: it is one of the identification details of the vessel in the registration and change of ownership procedure (mer.gouv.fr — buying, selling, registering a pleasure vessel, in French). The transfer of ownership guide details these procedures.

4. Photographing it

A sharp photo of the engraved number is one of the items of a serious sale file — and it is the one the buyer compares with the papers. For it to be useful:

• Clean the area; low-angle light (a lamp from the side, a low sun) brings out the engraving far better than a flash from the front.
• A close-up photo, legible character by character, without reflections.
• A second photo from further away, showing the number in place on the transom, with a landmark of the boat (name, bathing platform, ladder): it proves the close-up really comes from this boat.
• If you know where the hidden mark is, a photo of that too.
• Photograph the builder’s plate in the same way and, for each engine, the plate with its serial number.

In the Hullteam log, the photo of the hull number is one of the items on the file checklist: it counts towards the proof score, it is frozen in the sale file with its timestamped fingerprint, and the number entered on the boat’s record is compared with the one read on the registration document during the ownership check. For the buyer, it is the first point of the buying checklist; for the seller, it is five minutes that avoid an awkward question on the day of the viewing.