Patent for a new and improved dredging machine. This design consists in "[t]he combination, with a boat or the like, provided with depending hangers at its bow and stern, of the shaft journaled in said hangers, and provided with a spiral screw extending throughout its length" (lines 88-92). It is "for removing sand-bars and similar obstructions in the beds of harbors or in streams by loosening the sand or the like, so that it will be suspended in the water and carried off by the natural or created current" (lines 22-26).