Hull Numbers

From Skipper Wall, 8/24/04

The Official Word on Hull Identification Numbers.
from; Dennis M. Nelson, U.S. Coast Guard,
Chief Recreational Vessel Division,
U.S. Coast Guard National Documentation Center,
792 T.J. Jackson DR
Falling Waters, West Virginia 25419
(o) 304 271 2450 (e/m)

The number on the transom is the HIN (hull identification number) which the Coast Guard mandated in 1971 and is to used for "product recall". There are three formats and the first two were called straight year and model year format.

The new format was required after 1/1/84. All three formats comprised of 12 characters and all begin with a three letter designation to identify the manufacturer and called the MIC (manufacturer's identification code).

The next five designations are usually numbers that are the unique identifier or serial number...and the last four characters are where all three formats differ.

Under the New Format the number ABC12345C889 would be broken down as:
ABC is the MIC code for the builder;
12345 is the serial number of the boat;
C refers to month of production ( in this case March since the letters begin with "A" for January thru "L" for December);
8 would refer to the year of build (1988) and the last two numbers "89 would refer to the model year 1989.

A Straight Year HIN would be ABC123450883.
When you get to the last four characters "0883" the 08 refers to the month of production and the 83 would be the year of production.

The Model Year HIN would be ABC12345M84A with the characters "M84A" with the "M" indicating it was a model year format, "84" the model year and the "A" being the month of production with the "A" being August in the model year format thru "L" for July.

You can go to the Coast Guard home page at;, click on "Service we provide" in the upper left corner of the screen; when that page comes up, scroll down to "Recreation Boating Safety" and click on the "Manufacturers' Identification Code Database".

You can enter the three character MIC code for Islander Yachts (which is XLY) and see they were built in Irvine, CA and went out of business 5/28/86."


From Skipper:

Mr. Nelson,

Thank you so very much for the explanation of the HIN's for the Islander Boats. The reason for this e/m is: My own boat's HIN is XLYB3389M73L.

I deciphered it all except the "B" after the XLY.... Is this just a filler or maybe I need to reexamine my transom for correctness?
Maybe my "B" is an "8" or a sloppy "3"?

Thank you again, Skipper Wall


To; Skipper Wall

The 5 character serial number does not necessarily have to be all numbers so I would not consider the "B3389" as wrong. The old Chris-Craft company used letter designations to distinguish changes made during the model year, "A" being the original design and "B" the first change, etc. Since your boat was built in July and is a 1973 model perhaps the design was changed somewhat during the production year.

Dennis Nelson.

From: Ken/Monica Kropf
Sent: Wednesday, June 16, 1999 9:48 PM

I just purchased an I-36 and find the hull number XLY366201181-1-82. The 3 may be a B. What can anyone tell me about the boat from this?

Ken & Monica:

To answer your questions, the XYL366201181 1-82 breaks down like this:

XYL = Islander Yacht Inc.
36 = 36 ft.
620 = hull number (620th I-36 built)
1181 = hull laid up in November 81 and 1-82 = Date completed.

The Pathfinder is a Volkswagen diesel engine. They are still in business. They are headquartered in Montreal and their phone number is: 514-695-6676. You can call and talk to John Schrer. He can advise you on anything you want to know about that engine. Give him the serial number (on plate, on port side, inside engine housing).

Good Luck,

Harry Farrell, Pacific High,

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