RAPID n.
The part of a river where the current moves with great swiftness, but without actual waterfall or cascade; -- usually in the plural; as, the Lachine rapids in the St. Lawrence. Row, brothers, row the stream runs fast, The rapids are near, and the daylight's past. Moore.
ROUSTABOUT n.
A laborer, especially a deck hand, on a river steamboat, who moves the cargo, loads and unloads wood, and the like; in an opprobrious sense, a shiftless vagrant who lives by chance jobs. [Western U.S.]