I bought a boat from a private person in BC and brought it into Washington
by showing up at the customs dock
and telling them I wanted to import
the boat whereupon they impounded the boat.
Luckily, they let me put the boat in a slip at the marina and stay on the boat, although my car was close to the ferry
in Anacortes if I had to leave.
First, I recommend not importing a boat through a customs entry that is not familiar with the laws as they will not be able to be as helpful as people who do it often.
I was given a form which I filled out and they wouldn't accept until I hired a customs broker from a not very up to date list. The broker faxed the same form and it was accepted immediately. The thing was resolved in less than 24 hours. Mostly because I arrived late in the afternoon and had to wait until morning to finish and pay.
I could have saved some money
if I had known that the boat had lived in the US for some time before it moved to Canada. I was assuming it came new from Sweden
and went right to Canada.
Registering it in Washington
was also slightly difficult because Canada has different registrations and everyone from Customs to the state wanted to assume that I had stolen the boat until enough time passed, so initially everything was kind of provisional.
I would definitely line up a customs broker beforehand and go through a port that is used to importing things. On the other hand the Customs officers let me use their fax machine several times, so points for them being nice.
With the exchange rate at the time it was still a good deal even with paying the duty and customs broker fees
If I had known about needing the customs broker, I would have scanned the paperwork to them so it was ready when I got to the dock
even though I had planned to stay in Friday Harbor anyways. It was just a little more stressful than it needed to be.