A downrigger apparatus for trolling in which an electric motor is energizable for winding and unwinding downrigger line from a reel. A rotor is driven in reduced speed synchronism with the reel and automatically actuates up and down limit switches to stop winding and unwinding rotation of the reel by the motor. The down limit switch is carried by a support adjustable along the path of movement of the rotor through a range of positions corresponding to different lengths of line unwound from the reel, with cooperating pointer and indicia means to indicate the length of the line unwound from the reel.