the windvane pivots around a vertical alum tube. a horizontal beam is fixed to the lower edge. the beam carries a counter weight, and a c-clamp. just below the beam is a horizontal disc, fixed to the rudder tab. the centerpoint of the disc is on the axis of the vane, and the axis of the tab mounts. after the angle between the vane and tab is selected, tightening the c-clamp fixes the angle. and away you go... untested as yet, no guarantees.