I don't believe a single unattended foil with the rotation axis at 50% of the chord will point straight ahead at 15 knots. Until I see one, and the physics that explains why, I cannot agree that it is a good thing to have on a boat.
Linked rudders solve a lot of problems, but unless they work when one is raised, are no use. Rotating them aft is a solution, but is an extra layer of complexity. As the rudders have to turn for steering, turning them through 180 on a shunt is no big deal, unless they are mounted on the hull or utilise wheel steering, but even here, there are simpler methods.
regards,
Rob
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