There have been several variations on that over the years.
--There was oriental pottery unearthed in Equador a number of decades ago.
--One of Thor Heyerdahl's early ideas involved Hawaiians or other Pacific Islanders reaching British Columbia.
--Just recently comes the idea that the Chumash canoe (along the Santa Barbara channel) originated in the Polynesian area. Here is a link for this idea.
“sewn-plank boats” were a world wide design. The question is where were they first developed.