Happy to return the favor m8
Off the cuff, dual rudder
One suggestion comes immediately to mind is to set the rudders similar to an elevon mode (rc plane) and I should think all that would be req'd is about 15 degree's if it can be set up on a switch with preset position, variable wouldn't be req'd. Another consideration is to have the control arm on the rudder's 1/3 or so offset to allow the water to assist easing strain on the servo's. Do you still have an experimental platform to give it a go, could be a rudimentary setup to test strength and degree? Hope that helps
Cheers
Just hit me, back to sailing days with a dagger board only sideways and at a slight forward incline angle to drive the bow down a tad at the same time. It can be variable or switch controlled to a preset depth and could be easily set with a direct attachment such as a bell crank or likewise to one servo. The dagger board slot placed inside the hull hidden and almost at the transom would alleviate all stress on parts associated and allow you to go back to one rudder. This method would maintain steering functionality and with minor structural strengthening it's very doable, I like it
