When I live in Seattle, sometime I and my family go to Vancouver by a boat. If you get into Canada, you need submit some documents. It is the same as a fright. When you go to a foreign country, you should show a passport and some documents that you get in a plain. Anyway, I attached a link of CBSA so please cheick it out before you go to Canada.
http://www.cbsa-asfc.gc.ca/travel-voyage/pb-pp-eng.html