#dredging_bucket  a bucket for lifting material from a channel or riverbed
  supertype:  bucket__pail  a roughly cylindrical that is vessel open at the top
  subtype:  grapple  a dredging bucket with hinges like the shell of a clam
  part of:  dredge  a power shovel to remove material from a channel or riverbed
     part of:  dredger  a barge or barge-like vessel used for dredging

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