The only drawback I see is that in the "kickback" position, I would think there would be a lot more force on the gudgeon if you were trying to steer, and could possibly cause failure in that area.
During normal sailing the forces in the gougeons are relatively low. Higher loads occur with the blade pivoted back. Then, higher loads are generated in this design due to the longer distance between the rotation axis and the gougeons. However, the load is divided between two gudgeons, while the F-33 configuration puts all the load in one gudgeon only - and still works (but not as a beach cat).
I'm sure there is a way to work out the control lines so that you can secure the rudder in the down or mid-down postion.
Not necessarily lines. A control bar is a good option. The tiller bar can also be used.
My only question is when my leeward rudder kicks back when I'm on the wire in a blow with the spin up.
Agreed. If you are trapezing to the beach with the rudders down and your rudder kicks backs, I think you are in trouble regardless of rudder type...
For this specific situation the best rudder setup is the Dotan style - up, down, ready. Note that the Hobie and Supercat rudders are also problematic in the same situation. A pivoting dagger rudder would enable you to raise the blades vertically a bit before heading to the beach and steer the boat more effectively then with a pivoted rudder. An accidental kick back is... accidental.
And with that "T" rudder, if you are flying a hull, would that direct forces in the wrong direction? I can understand how it works on those Hobie Raves, since I think they don't roll (I think that's the term), but a cat pitches, rolls, and yaws
If your concern is keeping a foiled blade down using a pivoting dagger rudder, the answer is that both lines holding the rudder in position need to be fastened to separate kick-up cleats (or the control bar should be held in position fore and aft). This will keep the blade down.
If your concern is about the contribution of T foils when the boat moves changing the angle of attack of the foils (due to heeling, yawing, pitching, rolling, passing waves) then it is very complicated and I don´t know enough to answer.
Back to the pivoting dagger rudder, in another post someone expressed concern that the trailing edge of the blade would be too exposed. The rotating axis is a plastic tube, free to rotate over the inner bolt. The tube has to be softer then the blade, to protect it. It can even be coated with ruber, if desired. Otherwise, the trailing edge is as exposed as in a non-pivoting dagger rudder.
Cheers,
Luiz
