The hard part won't be the boat, its the trailer.
You will pay taxes (GST or HST, depending on your province) on the boat based on its value. If you get a good deal, be sure to bring the appropriate documentation.
The trailer will require going through the RIV. There is a well defined procedure that must be followed to the letter for first exporting from the US, then importing to Canada. See here: http://www.riv.ca/ImporterChecklist.aspx
Once imported, the trailer will need to pass provincial and federal inspections to allow you to insure and register.