If there is a HIN (required in the US beginning in 1972, dunno about Canada) make sure that the same HIN is on the title and bill of sale, and that it is sold "free and clear of all liens and encumbrances".
Even on a 25' boat, you might want to have it surveyed. If there is a problem below the waterline, with the keel, etc. the repairs or disposal costs can FAR EXCEED what your whole budget for the boat was. (There are problems above the waterline that can be just as bad.)