NSJ- Are those 'Prindle' (Nacra) rudder blades? Look just like the old P16,P18,P18-2, P19 blade shape and style.
Yes, they are inspired by the good oldfashioned Prindle style.
I made the blades and the castings all by myself. I can pull the blades down after starting in the break with a rope from the luff-side at the tramp.
That's the main reason why I have chosen for this old design.