Sailing
How does self-steering on a sailboat work?
Self-steering gear achieves this by presenting a vane directly into the wind. When the wind acts on either side of this vane, it tips, transferring this action through the mechanism below to either a rudder or a servo pendulum which acts on the main rudder, altering the boat’s course.
A long time ago I studied autopilots hesitantly, many videos explain this… I highlight in this post a presentation that I find excellent.