I took my oldest daughter and here boy friend fishing this morning. Well the fish had lock jaw and the wind came up. So we decided to go in. I thought that my daughter and her boyfriend would stay with the boat while I went to get the truck. Well I was almost to the truck when I noticed that they where fallowing me, they where on their way back to the boyfriends truck. So I quickly got in and headed back to the boat launch. I noticed that there was a middle aged black man walking swiftly to and down the pier. As I backed the trailer into the water I kept my eye on the black man. Just a the trailer started in to the water the black man got into my boat! I slammed the truck into park, grabbed the key from the ignition as I got out.As I was running down the pier I was yelling at the man that he had 1 second to get out of the boat or I was going to start shooting ( I had no gun with me but had my hand under my jacket like I was getting ready to pull one out of a shoulder holster)! The man jumped out of the boat and threw his hands in the air! I fallowed about 20 feet behind him telling no to turn around and and to keep walking of I was going to put 1 in him! As all of this is going on another man on the pier had called the cops. When the cops came they told me that he needed a boat to get away from the title wave that was coming and he needed to get to Ft. Worth. To make a long story short the cops said that they had dealt with him before, and that was really crazy and would probably be in a home soon.