windvane self-steering

Watching videos on #youtube channels, I couldn’t work out what the strange wing fitted to the stern was. Eventually, someone in a sailing chat answered my question: it was windvane self-steering. I wanted to find out more, as I’d never come across it in sailing lessons or books: https://youtu.be/BSEnKI66fek

The principle behind this #equipment is simple: set the vane for your course relative to the wind. If the yacht changes course, the wind tilts it. That movement operates the servo steering mechanism, bringing the boat back on course. All without electronics.