This shows the major dry docks and shipyards currently on the Great Lakes.
http://www.tmacog.org/Transportation..._Dry_Docks.pdf
I would also not be so quick to write off steel ships. Iron and steel were preferred instead of wood for ship hulls as early as the 1870's. Granted we would not see many ships in the 300m range, but with the wealth of iron ore still in the region it is possible for smaller ships to be built powered by wind and steam. Take fine vessel for instance:
https://en.wikipedia.org/wiki/SS_Great_Britain