As of November 1, 1972, all boats in use have been given a Hull Identification Number. The Hull Identification Number (HIN) is a Federal requirement. It can be located either on the starboard outboard side of the hull aft or the transom. Some people may need to look up a boat’s hull number to see if it’s owned by the seller, to check if it has any repair history, to see if it has been recalled and to see if the boat has been stolen. It is illegal to damage, change or remove the hull number unless the owner has permission from the U.S. Coast Guard Commandant. Nevertheless, thieves do alter these numbers in order to avoid getting caught. This is why it’s important to see if the hull numbers are free of any rippling or obvious handiwork. If it’s there, compare this to the boat’s repair history.