Sweep

1. A long oar used to row, steer, or maneuver an unpowered lighter or sailing vessel when there is no wind.
2. Rowing: A rower who rows with a single oar and primarily on only one side of a boat.
3. (v.) To search for an underwater object using a towed submerged line or device which will snag on the target.
4. (v.) To clear a body of water of dangers such s naval mines and obstructions, e.g., minesweeping.