Flatboat

A flatboat is a rectangular flat-bottomed boat with NOTE: "[bracketed]" wordings in the quote below are notes added to clarify

 There were a variety of specialized flatboats [eventually developed] to ship cargo to world markets. Some [later, meaning c. 1815–20, after steam boats became common] flatboats were built with raked bows to be used on return trips alongside steamboats, serving as 'fuel flats', first hauling wood, then coal. These flatboats with raked bows evolved into coal boats. (Later,) Coal boats were tied together in fleets to be pushed by steamboats. Those coal boats evolved into the steel barges of today (plying the rivers servicing the coal fields of the Ohio River watershed).
 —Nancy Jordan Blackmore, Janes Saddlebag square ends used to transport freight and passengers on inland waterways. The flatboat could be any size, but essentially it is large, sturdy tub with a hull.

A flatboat is almost always a one-way vessel, and is usually dismantled for lumber when it reaches its downstream destination.

 References 

Category:Ship types