They didn't use waterways to move steel from the Pennsylvania refineries to Norfolk, well, maybe they used some, but the majority went along the railroads. There's massive amounts of railroads heading to Norfolk:
This is freight rail by usage in 2010, note the two spurs heading to "Hampton Roads" along that north-south stretch going to Virginia. Hampton Roads is the actual US Navy shipyards right next to Norfolk Virginia. Likewise there's a lot of smaller spurs off this that go to various coastal ports that could easily handle greater traffic needed for shipbuilding.
Like I said, moving production from the heartland to the coast is pretty much a solved issue.