Dredging grab is mainly used to excavate and clean up the sludge of the river-way and channel in engineering ship and is also used to salvage and clean up the abandoned shipwrecks. Engineering ship in small size usually employs double rope dredging grab, engineering ship in large size usually employs four-rope of multi-rope dredging grab. Elevating capacity of dredging grab varies from several of tons to hundreds of tons.

Large dredging grab is made of thick plate and steel mixed with cast steel. The shape of the bucket is circular arc which is beneficial to excavate the sludge under water. Three-dimensional optimization design, proper bonding technology and nondestructive inspection test ensure the overall manufacturing quality and working life of dredging grab. Dredging grab has been widely used in dredging the channel and refloating operation at home and abroad and plays a major role in ocean engineering.