My dad is fiddling with a Billings Boats Dana 200 kit. He found it on a shelf and decided a little boat would make a change from bigger projects.
Needless to say, I got roped in to help with the technical stuff, and of course, despite the kit being suitable for RC, according to the box, you are on your own trying to fit the stuff.
Drive is easy, rudder less so. There's not a lot of space to fit everything so we had to build the rudder and post from the (static) wooden version and some brass tube.
To rotate the rudder, I cut a 4BA thread in the top of the post and made an arm up from a bit of brass. This is soldered to the nut and the screwed on to the post. It's help in place with a drop of superglue on the top.
The servo just squeezes under the deck and the whole thing is a bit tight. The linkage hooks through the arm, retained by a bent bit of wire fitted through a hole drilled in the fat wire.
It all works though, so now I just need to wire the boat up.