What is a Hull Identification Number?

The HIN regulations are quite easy to understand compared to some of the more complex regulations involved in boating, by which everyone must comply. We frequently receive many calls and messages on the subject, and we’d like to offer more information on HIN.

The HIN (“Hull Identification Number”) can be used to tell you the year the vessel was manufactured. Additionally, it can reveal the month, as well as other information you need to know about your vessel. 

Where to Find HIN on a Vessel?

The primary HIN must be permanently engraved or pasted on the hull on the starboard side of the transom within two inches of the top of the transom, gunwale, or hull/deck joint so that it can be seen from outside the boat. For registration purposes, to identify the vessel’s hull number some states may require a pencil rubbing or tracing of the hull number. To create a pencil tracing, place a blank piece of paper on top of the number and rub a pencil across the paper so that an impression of the number appears. If the rubbing is not clearly legible write the numbers you see adjacent to the rubbing and take a digital photograph.


SAMPLE hull number


Here’s how to read HIN:

ABC: This is the U.S. Coast Guard-assigned manufacturer identification code (MIC).

16355: This is the serial number assigned to the hull by the manufacturer. This may be a combination of letters and numbers. The letters “I,” “O,” and “Q” are excluded because they could be mistaken for numbers.

How to Tell the Year a Vessel Was Manufactured

Now look at the next letter:

C: This is the month of certification, indicating the month in which construction began. “A” represents January and “L” represents December. In our example, “C” means March.

4: This is the year of certification. The number is the last digit of the year in which the boat was built. “4” in this case designates 2004.

04: This indicates the boat’s model year.

Vessels manufactured or imported after or on November 1st, 1972 are required to have an HIN. If you see a vessel without one, it most likely was manufactured or imported before 1972. 

If the vessel has a transom, the HIN is most often found on a plate (metal or plastic) on the starboard side of the transom. If the vessel does not have a transom, then the HIN is most likely on the starboard side of the hull, within one foot of the stern and two inches of the top of the hull side. 

To conduct a search by HIN or Official Number (ON) through our site, use this vessel documentation search