Windvanes 101Crash Course in Selfsteering Systems
The Great Problem in Vane Steering
The average sailboat is a rather cluttered affair. Masts, sails, stays, shrouds and other necessary paraphernalia limit the size of the air vane sensor that can feasibly be used. Besides interfering with sails and rigging a very large air vane would also be heavy. When the boat gets moved about by wave action, inertia and the motion of the boat control a large and heavy vane, rather than the wind.
As only a relatively small air vane is feasible, the force of its signals are fingerlight at best and only featherlight in lighter winds, especially downwind. The problem of windvane self-steering involves getting these weak signals to steer a large yacht back on course, without the aid of any electric motors to boost the power of the air vane.