The rudders on the hulls rotate so the aft one is further from the end than the front one. On El and Vis, the beams are at 25%. The rudders work on El on the beams, didn't on RB. So not enough data to be conclusive. The Sol beams are closer to the centre, will have the rudders mounted on them so this will be another data point. Suspect it is as much to do with the rig, the beam, the drag of the ww hull, the size, shape and surface of the rudders as much as their fore and aft position.
Todd,
RB's rudders counter rotate unless they are disconnected.
rob
__._,_.___
.