A hull identification number must be displayed on all recreational boats the construction of which began after October 31st, 1972. The number consists of 12 characters, no less than one-forth of an inch in height, and must be affixed to the outboard side of the transom or, if there is no transom, to the outermost starboard side of the end of the hull that bears the rudder or steering mechanism. The HIN must be affixed above the waterline of the boat in such a way that alterations, removal, or replacement would be obvious and evident. Some states have registration requirements that differ from or exceed those above. Check with the state agency responsible for boat registration for any differences in your area.
Federal law requires the registration certificate to be on board whenever the boat is in use.