This from Good Old Boat:
Deciphering an HIN
Sponsored by Good Old Boat Magazine
How to read your boat's "birth certificate"
by Don Launer
Unless you have a really old boat, you probably have a set of 12 characters embedded on the upper starboard side of your boat's transom. This is your boat's birth certificate, the Hull Identification Number (HIN). It shows the parent-age and date of birth of your vessel. This identification is similar to the 17-character automobile identification number that's on the lower left side of any auto dashboard close to the windshield -- the Vehicle Identification Number (VIN). All boats that were either manufactured or imported after November 1, 1972, are required by law to have an HIN and -- just as you would have a duplicate of your own birth certificate -- it's a good idea to record your HIN or a rubbing of it in your records.
The 12-character HIN bears no relationship to your state boat registration number, the number you apply to the port and starboard sides of your bow (unless your boat is documented). Instead, the HIN is federally mandated. In spite of the fact that it is a federal number, it must be shown on the state boat-registration certificate.
To read your boat's birth certificate, you have to be able to decipher the format of those 12 characters on the stern. There have been several formats for the HIN over the years, and it's probable that new formats will emerge in the future. From its inception on November 1, 1972, the HIN was designated by one of two formats.
HIN formats
The manufacturer had a choice of using either the model year format or the straight-year format, both of which identified the month and year of production.
• Characters 1, 2, and 3 of the HIN are the Manufacturer's Identification Code, and are assigned by the federal government.
• Characters 4 through 8 are the alpha-numeric serial number, which is assigned at the discretion of the manufacturer (I, O, or Q cannot be used in this serial number).
• In the model-year format, the 9th character will always be M, indicating the manufacturer is using the model year format. Then characters 10 and 11 indicate the year, and character 12 is a letter indicating a month, starting with August. Thus, if characters 9 through 12 of the HIN were "M80B," the boat was built in September of 1980. Why the lettering of the months in the model year system began with August is incomprehensible.
• In the numerical straight-year format, characters 9 through 12 are simply the month and year of production. Thus, 0879 would indicate August 1979.
This Hunter sailboat shows the manufacturer's code, HUN, and since the hull is pre-1984, the model-year format was selected. Many manufacturers add additional, optional information to the goverment'mandated HIN. In this case, the -27 included after the 12-character HIN shows
that this boat is their 27-foot model. New format
Optional, as of January 1, 1984, was a new-format version, simply called new format. This format became mandatory August 1, 1984, replacing the two previous formats.
• In the new format, characters 1, 2, and 3 of the HIN are still the Manufacturer's Identification Code. Sometimes the letters of this manufacturer's code easily identify the manufacturer. In other cases they bear no relationship to the manufacturer's name.
• Characters 4 through 8 are still the alpha-numeric serial number assigned at the discretion of the manufacturer. Some of these manufacturer-assigned characters are laid out very logically, and some defy logic. On a 37-footer, which is hull #51, the number might be 37051; but it also might be a set of characters that only makes sense to the builder.
• Character 9 indicates the month of manufacture or certification. A designates January, B February, and so on through December (a big improvement over the original lettering system that started in August).
• Character 10 is a numeral that indicates the last digit of the year of manufacture or certification.
• Characters 11 and 12 indicate the model year. Thus, 82 would indicate the boat's model year was 1982.
• Some manufacturers also add additional information after the HIN, such as -27, which might indicate that this is their 27-foot model.
After August 1, l984, boat manufacturers were required to display two identical Hull Identification Numbers, one on the outside starboard side of the transom, within two inches of the top of the transom, gunwale, or hull-to-deck joint, whichever is lowest. On boats where this is impossible, such as double-enders, the HIN must be on the starboard side of the hull, within one foot of the stern and within two inches from the top of the hull, gunwale, or deck joint.
The second HIN must be inside the hull in an unexposed location or beneath a fitting or item of hardware.
The HIN characters, both inside and outside the hull, must be no smaller than ¼-inch high, but many manufacturers make them much larger. It is illegal for anyone to alter or remove one of these numbers without written permission of the Commandant of the Coast Guard.
I have seen the "August Start" of the Hunter model year mentioned several places so it is either true or a persistent internet legend. Also. I have never discovered the second 'hidden' HIN on my boat, although I have been in pretty much every nook and cranny. Jim
Deciphering an HIN
Sponsored by Good Old Boat Magazine
How to read your boat's "birth certificate"
by Don Launer
Unless you have a really old boat, you probably have a set of 12 characters embedded on the upper starboard side of your boat's transom. This is your boat's birth certificate, the Hull Identification Number (HIN). It shows the parent-age and date of birth of your vessel. This identification is similar to the 17-character automobile identification number that's on the lower left side of any auto dashboard close to the windshield -- the Vehicle Identification Number (VIN). All boats that were either manufactured or imported after November 1, 1972, are required by law to have an HIN and -- just as you would have a duplicate of your own birth certificate -- it's a good idea to record your HIN or a rubbing of it in your records.
The 12-character HIN bears no relationship to your state boat registration number, the number you apply to the port and starboard sides of your bow (unless your boat is documented). Instead, the HIN is federally mandated. In spite of the fact that it is a federal number, it must be shown on the state boat-registration certificate.
To read your boat's birth certificate, you have to be able to decipher the format of those 12 characters on the stern. There have been several formats for the HIN over the years, and it's probable that new formats will emerge in the future. From its inception on November 1, 1972, the HIN was designated by one of two formats.
HIN formats
The manufacturer had a choice of using either the model year format or the straight-year format, both of which identified the month and year of production.
• Characters 1, 2, and 3 of the HIN are the Manufacturer's Identification Code, and are assigned by the federal government.
• Characters 4 through 8 are the alpha-numeric serial number, which is assigned at the discretion of the manufacturer (I, O, or Q cannot be used in this serial number).
• In the model-year format, the 9th character will always be M, indicating the manufacturer is using the model year format. Then characters 10 and 11 indicate the year, and character 12 is a letter indicating a month, starting with August. Thus, if characters 9 through 12 of the HIN were "M80B," the boat was built in September of 1980. Why the lettering of the months in the model year system began with August is incomprehensible.
• In the numerical straight-year format, characters 9 through 12 are simply the month and year of production. Thus, 0879 would indicate August 1979.
This Hunter sailboat shows the manufacturer's code, HUN, and since the hull is pre-1984, the model-year format was selected. Many manufacturers add additional, optional information to the goverment'mandated HIN. In this case, the -27 included after the 12-character HIN shows
that this boat is their 27-foot model.
Optional, as of January 1, 1984, was a new-format version, simply called new format. This format became mandatory August 1, 1984, replacing the two previous formats.
• In the new format, characters 1, 2, and 3 of the HIN are still the Manufacturer's Identification Code. Sometimes the letters of this manufacturer's code easily identify the manufacturer. In other cases they bear no relationship to the manufacturer's name.
• Characters 4 through 8 are still the alpha-numeric serial number assigned at the discretion of the manufacturer. Some of these manufacturer-assigned characters are laid out very logically, and some defy logic. On a 37-footer, which is hull #51, the number might be 37051; but it also might be a set of characters that only makes sense to the builder.
• Character 9 indicates the month of manufacture or certification. A designates January, B February, and so on through December (a big improvement over the original lettering system that started in August).
• Character 10 is a numeral that indicates the last digit of the year of manufacture or certification.
• Characters 11 and 12 indicate the model year. Thus, 82 would indicate the boat's model year was 1982.
• Some manufacturers also add additional information after the HIN, such as -27, which might indicate that this is their 27-foot model.
After August 1, l984, boat manufacturers were required to display two identical Hull Identification Numbers, one on the outside starboard side of the transom, within two inches of the top of the transom, gunwale, or hull-to-deck joint, whichever is lowest. On boats where this is impossible, such as double-enders, the HIN must be on the starboard side of the hull, within one foot of the stern and within two inches from the top of the hull, gunwale, or deck joint.
The second HIN must be inside the hull in an unexposed location or beneath a fitting or item of hardware.
The HIN characters, both inside and outside the hull, must be no smaller than ¼-inch high, but many manufacturers make them much larger. It is illegal for anyone to alter or remove one of these numbers without written permission of the Commandant of the Coast Guard.
I have seen the "August Start" of the Hunter model year mentioned several places so it is either true or a persistent internet legend. Also. I have never discovered the second 'hidden' HIN on my boat, although I have been in pretty much every nook and cranny. Jim
