>>1725268The TL;DR is that most transportation on the lakes prior to the 1860s/50s was passenger transportation. They used typical side wheel steamer type designs like this picture.
When iron ore became the trade commodity of choice, and there were a lot of old passenger steamers laying around, they decided it would be easy to just rip the passenger sections out, keep the bridge that was built in the front (for visibility purposes) and the stern equipment (there so embers wouldn’t catch boats on fire) and use the middle for the ore in a hold.
