A stern rudder is used to maintain a straight line or to make minor course corrections. It has no propulsive component, and is ineffective when the kayak is still or moving very slowly. It is particularly useful in following seas and surf. It can turn the boat efficiently and can evolve into a reverse sweep stroke or a stern low brace. Place the paddle six inches away from the stern hull, as though you are about to perform a reverse sweep. Rotate the torso sharply toward the paddle, so that the paddle is completely over the water. Place the blade as far to the stern as you can. Push the blade out away from the boat for an onside turn, or bring it nearer the hull for an offside turn. The angle of the paddle blade can also affect the degree of turning, and provide support at the same time. Angle the top of the blade away from the hull for a better onside turn, or angle the blade toward the hull for an offside turn. With enough forward momentum, you can alternate blade angles in a stern rudder to "thread the needle" between two obstacles, such as tree branches in a stream. We like this stroke in following seas because it provides both direction and support without losing much momentum.