JOHN M WILLIAM CO HIN Decoder
Hull Identification Numbers beginning with JMW were assigned by the US Coast Guard to JOHN M WILLIAM CO of MT DESERT, ME. The builder is listed in the USCG MIC database. Enter the full 12-character HIN below for build date, model year, and serial — free, no account.
MIC
JMW
Location
MT DESERT, ME
In business
since 1975
Status
Listed active in USCG records
JOHN M WILLIAM CO built hulls across both HIN eras (1975–present): boats before August 1984 carry legacy straight-year or model-year date codes; later hulls use the current month-letter format. The decoder handles all three.
Free · no account · the HIN is on the transom, upper starboard (right) corner
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JOHN M WILLIAM CO HIN FAQ
What does a JOHN M WILLIAM CO HIN look like?
It starts with the three characters "JMW" — the Manufacturer Identification Code the US Coast Guard assigned to JOHN M WILLIAM CO — followed by a 5-character hull serial and a 4-character date code, 12 characters total. JOHN M WILLIAM CO built hulls across both HIN eras (1975–present): boats before August 1984 carry legacy straight-year or model-year date codes; later hulls use the current month-letter format. The decoder handles all three.
Is JOHN M WILLIAM CO still in business?
USCG records list JOHN M WILLIAM CO of MT DESERT, ME in the MIC database (registered 1975).
How do I decode the year on a JOHN M WILLIAM CO HIN?
On current-format HINs the last two characters are the model year and the 9th–10th encode the certification month and year. JOHN M WILLIAM CO built hulls across both HIN eras (1975–present): boats before August 1984 carry legacy straight-year or model-year date codes; later hulls use the current month-letter format. The decoder handles all three. Enter the full 12-character HIN above and the decoder works it out, including the legacy formats.
Other builders in ME
Sources: USCG Manufacturer Identification Code database (uscgboating.org, refreshed monthly) · HIN format per 33 CFR 181 subpart C. Cite this page: CarWhere, "JOHN M WILLIAM CO HIN Decoder," carwhere.com/hin-decoder/jmw, last verified 2026-06-12.