sorry if Im intrude here , I would like to clarify some technical aspects of S9.
this cat was born and raised in Cesenatico, here there are shallow waters, steep waves, wind or light or strong.
tilting the rudder at 45 ° allows you to have more immersed rudder surface therefore more control, using the vertical elevating rudder system we did not have enough surface immersed to govern the boat.
S9 is designed to do foiling but also semiplanning mode (floating), this to facilitate those who have never used a catamaran (an evolutionary path using only one cat, S9 is the only foiling boat that can do this), so these rudders were the best way.
however we often noticed that we could take the sea only by adjusting main sail and jib without using rudders, even with 1.5 m waves.
I do not like L foils , too much torsion in higth speed , T shape much more balanced .
p.s.: Im wery wery happy about Martin and Charlie work around foilingboat tests , this make more clear many things , hope you go on mates .
regards . Michele