The same rudders were used on the Stiletto catamarans in the 70' and 80's. I liked them. Easy up and down except at speed. Had to use my foot at the back of the rudder to push them in and down. On the Stiletto 23's, we used bungee cords to hold them down at speed. The bungee runs from the rudder pivot bolt over the top of the rudder and back down to pivot bolt.

my 2 cents

Spinakerjohn