Abstract: A watercraft propulsion system is provided for maneuvering and positioning a dredge or weed harvesting craft in shallow waterways and includes a pair of booms positioned adjacent the port and starboard sides of the craft. Submersible and reversible motors are provided at the remote end of each pivotally mounted boom for independently driving wheels provided with a plurality of circumferentially spaced blades. The wheels include an enclosed buoyancy chamber to offset the weight of the wheels and the booms, and the blades are removable and may be provided in different configurations to accommodate different operating conditions. A pumping unit including a cutterhead is provided whereby the watercraft can perform dredging or aquatic weed harvesting operations.

Abstract: A method and apparatus for cutting aquatic vegetation is provided which substantially reduces the tendency to wrap or clog conventional cutterheads. A cutterhead of the present invention includes a plurality of radially oriented rotatable cutting members which cooperate with stationary cutting teeth to tear weeds and other aquatic vegetation. The rotatable cutting members are preferably spirally mounted along a smooth rotatable drum to inhibit draping of the vegetation during cutting. Recessed cutting teeth are located at the ends of the drum to further inhibit aquatic vegetation from passing through gaps between the drum and the cutterhead shroud. The shroud directs the cut vegetation to a submersible pump so that it may be pumped to a remote site.

Abstract: A pump for handling abrasive materials includes a housing having two chambers. A shaft mounts a high pressure impeller and a high volume impeller in respective chambers of the housing, each chamber having a separate and opposite inlet. A channel is provided to divert a portion of the flow generated by the high pressure impeller to a purge ring adjacent the primary inlet corresponding to the high volume impeller. The purge ring directs a flow of relatively abrasive-free liquid toward the inlet to reduce wear on the housing and high-volume impeller. Another part of the flow from the high pressure impeller is diverted through the housing to isolate portions of the housing and the high volume impeller from the abrasive material laden intake through the primary inlet.