Preparations for crossing the Indian Ocean single-handed. A windvane is a mechanical device to steer a sailboat – self-steering by keeping a constant course to the wind. It is essential equipment for single-handed ocean passage. The wind moves a “paddle” which moves a rod which rotates an “oar” in the water. The speed and force created by the boat moving through the water creates the power to lift the oar to port or starboard. This pulls on control lines attached to the tiller – and the tiller rotates the rudder. When the boat comes back onto course, there is equal pressure on both sides of the paddle and the vessel sails in a straight line. If the boat wanders a little, the windvane moves the boat’s tiller-rudder to make a correction.