With respect to the ships brought in by BC Ferries, the duty was paid on them, so I'm not sure exactly what your question is.
In summer 2007, there was a case where a particular ferry sank. It was a ferry that provided service to the north coast of B.C. There was work done on looking to see if a ship could be built in Canada in the very near term to replace this important service to northern B.C. It was determined that it couldn't, so a ship was brought in by BC Ferries. On that particular ship, the duty was remitted.