Mechanical dredges are barges equipped with a duty cycle crane that can utilize a variety of clamshell buckets for excavation. The material is loaded in to hopper barges or scows and hauled to the disposal site by tugs. The material is either bottom dumped at an offshore disposal site or pumped upland with a hydraulic unloading unit. Mechanical dredges are employed when the hauling distance is not suitable for pipeline dredging and the configuration of the dredging area is not conducive to hopper dredges.
The hopper dredges are best suited for project requirements that call for a long distance transit of dredged materials, typically in offshore environments. The “long haul” is utilized for beach nourishment, reclamation, and navigation maintenance projects. Once the vessel’s hopper is loaded with dredged materials, the ship will sail to its discharge point- either an offshore disposal location for a bottom dump or to a pipeline connection for pump-off to a shoreline.
Cutter suction dredges are barges outfitted with a rotating cutter head that excavates the bottom, feeding the dredged material to a pump system that transports the sediments via pipeline to the discharge point. This method is used for dredging mud, clay, sand and rock. Cutter dredges are deployed for new work and maintenance navigation projects, shore protection and reclamation projects. The Weeks’ fleet encompasses a variety of cutter dredges capable of inland and offshore work.