The waters of Lake Superior have a tumultuous and sordid history to them. They are one of the busiest commercial waterways in the world, despite its relatively remote location. For the last 200 years, boats shipping out the locally mined copper ore have passed through the Soo Locks.
The problem with shipping from Lake Superior is that it is about 7m higher than Lake Huron, the Great Lake it connects to via the St. Mary’s River. In order to combat this issue, the Soo Locks were built. Freighters, or any boat in really, enter the locks in a canal built to bypass the rapids on the Canadian side.
The largest size they can handle is just over 1000 feet (305 meters) and so all Lake Freighters are built for that. They are also thinner than most ocean freighters for the sole purpose of fitting through the Locks and navigating the St. Mary’s River between Lakes Superior and Huron.
The twin cities of Sault Ste. Marie (said as Soo Saint Marie) are on both sides of the river. Though I have more of a feel for the Michigan side, Sault, Ontario is actually the biggest city in the region.