A self steering system for a sailboat has a rotatably and pendulously supported servo blade or "oar" member, which is suspended in the water behind the boat. A central body portion is attached to the transom of the boat. A pendulum body having two lever arms or "winglets" which extend generally in opposite directions is fixedly supported on a shaft suspended below the central body portion. A line is attached to each of the tips of the lever arms. Each of these lines runs upwardly and through separate blocks to the boat's steering control. A wind vane is installed on the top of the assembly and drives a push rod, which is coupled, to the servo blade. In operation, the wind vane provides a motional signal in accordance with changes in the heading of the boat from a preset heading, this motional signal operating to drive the servo blade, which controls the sailboat's main rudder, to bring the boat back to its preset heading.