There’s been a massive engine swap-out on Great Lakes steamers.
The Obango ban on N6 fuel meant cutting a hole in the side and lifting out the steam engine, replacing it with a marine piston engine or engines..
Since I was a machinist in the 70s i have been interested in different engines, especially radial engines, the B-29 WASP engines. But those giant Diesel engines that are the size of an apartment building are incredible.