Along with the USCG Bill of sale
you will also need the removel of documentation
form and a Free of leins/mortages form from the USCG in order to satisfy Transport Canada
That is what they asked me for when I imported a boat from the US 6 years ago.
You also need to select three names as, unlike the US, no two boats in Canadian Registry can have the same name. I chose an unregistered name that I really wanted and two that were already taken to make sure.
You can check names here,,
Vessel Registration Query System
will also issue a temp. renewable registration
so you can reflag the boat in Panama
without bringing it home (and paying tax)