Here are a couple of photos of the old towboat Sprague, the largest such boat ever to run the inland rivers. They were sent to me by my brother, Cliff Richie, who took them probably in 1959, when the Sprague visited Pittsburgh for the city's bicentennial.
Yeah, the boat was big, more than 300 feet long. For comparison, a coal barge is only 195 feet.
If you want a quick history of the Sprague, here is one site.
And here, courtesy of C.R. Neale, is a clipping of a newspaper article when the Sprague was being towed backed to its home base on the Mississippi River.
The last I heard, the sternwheel was sitting alone on the banks of the Mississippi.