An early St. Lawrence Seaway expands inland wartime shipbuilding

How would an early St. Lawrence Seaway have affected Allied shipbuilding in the Second World War?

It would open Great Lakes yards to ocean delivery of merchant ships, escorts, and potentially cruiser-sized ships or escort carriers, broadening the Allied industrial base.

A larger and earlier seaway would remove the dimensional barriers that trapped many Great Lakes hulls inland. Regional yards could then contribute merchant ships and escorts directly to the Atlantic. Cruiser-sized warships and escort carriers are plausible upper-end products, depending on locks, draft, and bridge clearance. The result would be a wider industrial base rather than a replacement for the established coastal naval yards.