The method relates to the recovery of fine sand on floating production equipment in the form of a floating grab-bucket type excavator or floating bucket chain dredger. In this case, the dredged material is dewatered and transported to shore via floating conveyor belts. The dredged material is transferred to dewatering screening machine having a dewatering deck with a dewatering coating. Below the dewatering deck the screening machine has a blind bottom covering the entire surface area, whereby in the direction of conveyance the end zone is provided with a discharge. The discharge is directed at a hydro belt separator, which has a revolving endless conveyor belt with a washing trough as the separation bed, and an ascending part leading away from the washing trough. The running direction of the conveyor belt is in the direction of the ascent, whereby the dredged material is transferred at the discharge of the screening machine to the washing trough of the hydro belt separator.

A dredge includes a primary grizzly with a sieve for separating dredged material initially into recoverable and discharge portions. A second or auxiliary grizzly and sieve are also provided on a chute extending from the primary grizzly to further remove remaining recoverable material from the portion of material discharged from the primary grizzly. A gate is provided for selectively opening and closing access to the auxiliary grizzly depending upon the make-up of the material discharged from the top of the primary grizzly. The combination of the primary and auxiliary grizzly provide for increased efficiency and effectiveness in recovering a larger percentage of recoverable material from a water-based dredging operation.