A boat’s HIN has 12 characters: the first three are the builder’s Coast Guard code, the next five the serial number, then the month and year it was built and its model year. SERR2727K900 is a Sea Ray built in November 1999, model year 2000.
Who built it, when, and for which model year. Then the Copart and IAA listings in our archive that carried it.
Hull identification number
SER
Builder
R2727
Serial
K
Month
9
Built
00
Model yr
Every boat sold in the US since November 1972 carries a 12-character HIN, molded or plated into the upper starboard corner of the transom and repeated somewhere hidden on the hull. Canada uses the same layout. A 14-character HIN is the same twelve with a country code in front (US-, CA-).
Built since August 1, 1984
ABC 12345 D4 05
| 1–3 | Manufacturer identification code (MIC), assigned by the US Coast Guard |
| 4–8 | Serial number, chosen by the builder (no I, O or Q) |
| 9 | Month of production: A = January … L = December |
| 10 | Last digit of the year of production |
| 11–12 | Model year |
November 1972 – July 1984
ABC 12345 M83 B
| 9 | Always M |
| 10–11 | Model year |
| 12 | Month of production, counted from August (A = August … L = July) |
November 1972 – July 1984
ABC 12345 08 79
| 9–10 | Month of production (01–12) |
| 11–12 | Year of production |
The two pre-1984 formats were applied unevenly by builders, so the decoder labels their dates as estimates.
Partly. The number itself says only who built the boat and when. Searching it here also shows any Copart or IAA listing in our archive that carried it, with damage, title and bids. It does not show theft, liens, registration, or damage that never reached these two auctions, so a clean result is not a clean history.
On the upper starboard corner of the transom, molded in or on a plate, with a duplicate hidden somewhere inside the hull. Comparing the two is a basic check on a used boat.
Boats built from November 1972 to July 1984 used two other formats: a model-year format with an M in position 9, and a straight-year format with the month and year in the last four characters. Builders applied them unevenly, so treat their dates as estimates.
It is the same 12 characters with a two-letter country code in front, such as US- or CA-. The decoder reads both.
The decoder says so: a serial using I, O or Q, or a date block that matches no format. It can be a typing mistake or a homemade hull. It can also mean the number was altered, so check it against the boat’s paperwork before buying.
The format is set by US Coast Guard rule 33 CFR Part 181, Subpart C. eCFR
Manufacturer codes we have matched to the builders the auctions listed their boats under. Any other code still decodes, and its page shows which makes the auctions filed it under.