As with any State Licensed Vehicle, go with to the DMV/License Center office and make sure the ownership/Title gets transferred.
Not as likely to have problems with a boat, but if you ever sell a Car/Truck/etc. make sure it gets transferred at the License Center. My wife used to work at one in Chaska and heard many HORROR stories of people not doing that and relying just trusting they would. One case a woman was Arrested on a Hit & Run Warrant on a vehicle they had sold privately approx a year before. Only saving grace, was her husband came in with the Bill of Sale and Reciept from the Title. In another Case a guy got a letter stating all of his vehicle had to have WHISKEY PLATES due to the buyer getting a DUI.
Good Luck