dredge 1 
(drĕj)
(drĕj)n.
1. Any of various machines equipped with scooping or suction devices and used to deepen harbors and waterways and in underwater mining.
2. Nautical A boat or barge equipped with a dredge.
3. An implement consisting of a net on a frame, used for gathering shellfish.
v. dredged, dredg·ing, dredg·es
v.tr.
1. To clean, deepen, or widen with a dredge.
2. To bring up with a dredge: dredged up the silt.
3. To come up with; unearth: dredged up bitter memories.
v.intr.
To use a dredge: dredging for alluvial gold.
[Middle English dreg- (in dreg-boat, boat for dredging); akin to ; akin to Old English dragan, to draw.]
dredge1