Originally Posted by Jeff F
Agree with the above. But I'm not sure that attention is always paid to the country of origin. I've imported bicycles from the US that were made in Taiwan and have always just paid the HST. When I brought my Mainship into Canada I cleared customs and declared the boat over the phone and paid HST with my credit card. I don't recall any questions about where it was built. Very simple and straightforward, and I had actually obtained the Canadian licence prior to importing the boat - the whole process is less rigorous than importing a car. So my advice is to be prepared to pay the duty but wait until you are asked to pay it.
While I agree with the abovementioned there are a couple of points to clarify.
The Customs data base is made up of manufacturers and their origins. So they knew your Mainship was made in the US and was duty free.
Items of lower dollar value are often than not just processed with HST because they can't be bothered to research for the duty. If it's a high value item (boat) good chance they will especially when it's subject to follow-up scrutiny internally.
So bottom line. Don't volunteer to pay but factor it in your numbers and hope for a windfall.