showboat

A showboat, or show boat, was a form of theater on a riverboat that traveled along the waterways of the United States, especially along the Mississippi and Ohio rivers. A showboat was basically a barge that resembled a long, flat-roofed house, and in order to move down the river, it was pushed by a small (and misleadingly labeled) towboat, also known as a pusher, which was attached to it. It was difficult to put a steam engine on it and still have a large theater, since the engine would have had to be placed right in the auditorium.