Boat How Do I Change My Boat Title For The Correct Length Of Boat?

How do I change my boat title for the correct length of boat? - boat

He bought a boat for some time and not realized the size of my title suggests, this is a 15 'when the boat is actually a 18'. There are no identification numbers on the boat is a 1970th Can the size of the title, if I put numbers on the boat title or not? Not sure where to go because the owner of the boat is not where he is now. Any information would be useful. I live in Florida.