Source : Webster's Revised Unabridged Dictionary (1913)

Dredger \Dredg"er\, n.
   1. One who fishes with a dredge.

   2. A dredging machine.

Dredger \Dredg"er\, n. (Cookery)
   A box with holes in its lid; -- used for sprinkling flour, as
   on meat or a breadboard; -- called also {dredging box},
   {drudger}, and {drudging box}.

Source : WordNet®

dredger
     n : a barge or barge-like vessel used for dredging