From wikipedia:

The Durham boat was a large wooden, flat-bottomed, double-ended freight boat which was in use on many of the interior waterways of North America beginning in the middle of the eighteenth century. They were displaced by larger, more efficient canal boats during the canal era beginning with the opening of the Erie Canal in 1825. The Durham name became associated with this boat type due to their use by the Durham Ironworks of Durham, Pennsylvania for hauling freight on the Delaware River.[1] They are also noted for their use in George Washington's crossing of the Delaware River during the American Revolution.