Hopper dredger (TSHD)

A trailing suction hopper dredger (TSHD) is a self-propelled dredging ship that lowers one or two suction pipes (drag heads) to the seabed and sucks a sand-and-water slurry into an onboard hopper while steaming ahead, then sails to a disposal or reclamation site to dump or rainbow the load. The capacity unit is hopper volume in cubic meters: the Jan De Nul vessel Cristobal Colon, built by La Naval in 2009 at 223 meters, holds about 46,000 cubic meters and can dredge to 155 meters depth, the largest of the type. TSHDs do the bulk of capital and maintenance dredging for channels, ports, and land reclamation because they need no fixed pipeline or anchors.