I agree you can have completely non-electronic sensors. Case in point: the sensor wand on a Flying Moth sailboat: http://www.sailmagazine.com/racing/regattas/l

I agree you can have completely non-electronic sensors. Case in point: the sensor wand on a Flying Moth sailboat: http://www.sailmagazine.com/racing/regattas/learning-to-fly-2/ http://www.sailmagazine.com/racing/regattas/learning-to-fly-...