I think you want to LICENSE it rather than REGISTER it. Registration is a very complex process, usually for commercial boats or ones going offshore. It's especially complicated for boats not built in Canada - you have to get a letter from the country where it's built (US?) that releases it from them.
Get it licensed - you just need bill of sale, HIN, etc. and it's free. Service Canada (as in how a bull "services" a cow...) does the licensing.
druid