Boat HIN decoder: reading a hull identification number

The structure

A modern hull identification number is 12 characters, in three parts:

Position	Part	What it identifies
1–3	Manufacturer identifier code (MIC)	The company that built the hull
4–8	Serial number	That builder’s own identifier for the hull
9–12	Date section	Certification date information, closely tied to model year

That is the whole format. There is no hidden condition data in it, no ownership information and no accident history — the number is an identifier, and everything else is a record filed against it elsewhere.

What each part is good for

The manufacturer code tells you who actually built the hull, which is not always the brand on the side. Hulls built by one company and badged by another are common, and a MIC that does not match the brand name is worth a question rather than an alarm.

The serial number is mainly useful for matching: hull, title, registration, insurance and any service records should all agree.

The date section gives you a certification date. Treat it as the strongest available cross-check against a seller’s claimed model year — a boat advertised as three years newer than its HIN suggests is a conversation worth having before anything else.

What the format cannot tell you

• Anything about condition, hours, maintenance or repairs
• Who owns it or has owned it
• Whether it has been in an accident, stolen or salvaged
• Whether the number itself is genuine

That last one matters most. A HIN decodes the same way whether or not it belongs to the hull it is attached to, which is why the physical check — is the plate original, is there a matching duplicate elsewhere on the hull — comes before any decoding at all. See where the HIN lives and how to check it.

Older and non-standard numbers

Hulls built before the current format was standardised may carry shorter numbers or a different layout, and imported hulls follow their own country’s conventions. A number that does not fit the 12-character pattern is not evidence of anything on its own; it is a reason to check the era and origin of the boat.

Era-by-era format changes and the current published MIC lookup: [RESEARCH REQUIRED] we will cite the official reference rather than reproduce a list we have not verified.

Looking up what the code belongs to

Decoding the structure is free and you have just done it. Finding out which company a manufacturer identifier belongs to, and what records exist against the serial, is a separate step:

• The manufacturer: the U.S. Coast Guard publishes manufacturer identifier information. [RESEARCH REQUIRED] we will link the current official lookup here once verified.
• The records: see registration lookup for the free state route, and history reports for a consolidated paid search.

A decoder is coming to BoatSharp Tools. It will decode structure, which is real work we can do honestly in your browser — it will not pretend to query a database it cannot reach.