Very neat and nice! I am thinking about doing the same thing with some slight modifications:
1. I would like to use the rotary action of the servo post to rotate the throttle arm, so I do not have any any bellcranks in the system. Fewer moving parts. I think Zipp kits offers this hardware setup.
2. I would like to use a project box for my waterproof area. I can get one with a rubber lid gasket, and mounting lugs to mount it to raised plywood blocks on the floor. 4 screws to tighten lid.
Your rudder servo setup is very nice. Clean, straight, tough.. have some general questions:
1) In general, do you worry about getting water in your boat while running? Did you keep you pipe cooling vents open?
2) I notice that you kept some of your upper cross- frames intact. Were you concerned about the hull twisting?
J.B.