To look up a hull identification number, or HIN, locate the number on the boat's hull. Input the number into a search page for the information you wish to look up, such as the U.S. Coast Guard's boat recalls search or a company's boat history records search.
A boat's HIN is usually located on its hull's exterior on the starboard side, though its exact location depends on the type of boat. The first three digits represent the manufacturer identification code, or MIC; the next five digits comprise the hull serial number; and the last four represent the date of certification or manufacture. Manufacturers hide a second identical HIN somewhere on the boat to prevent easy removal of both numbers. Putting the MIC into the U.S. Coast Guard's manufacturer search gives you the name and contact information for the boat's manufacturer, and putting the MIC, serial number and date into the recalls search allows you to see if a boat manufacturer recalled a boat for defects.
The U.S. Coast Guard also maintains the Port State Information Exchange in compliance with the Freedom of Information Act. The database provides specific data on both American and foreign vessels, including recreational boats, that have sailed in U.S. waters. Recently the Coast Guard added the ability to search this database by hull ID numbers.