Abstract: An automatic down rigger control system is disclosed for use with a down rigger trolling line operated by a motor for raising and lowering the trolling line. Via the motor, the control system automatically lowers an end of the trolling line to a predetermined depth point and automatically raises the end of the trolling line to a predetermined surface point. Also, a manual operation mode is provided for selectively raising and lowering the trolling line to a depth other than the surface point and predetermined depth point.

Abstract: An automatic trolling depth controller is disclosed for a fishing boat employing a downrigger system. A sonar depth indicating unit with a sonar transducer continuously measures changing depth as the boat trolls. A depth control unit is connected thereto which automatically raises and lowers the trolling line via a reversible motor in response to depth indicating signals of the depth indicator unit so as to automatically maintain the end of the trolling line at a substantially constant given spacing from the bottom despite variations in lake depth as the fishing boat trolls.