I just found plans for a small and I hope simple Paddlewheel model.

The plans are from Radio Control Modeler Magazine (RCM).

The boat is 16.5" length 6" beam, small DC moter, 2 ch RC, build-up
balsa and plywood, one sheet 34.75"x60.75.

To get plans follow below:

www.rcmmagazine.com
In banner click "RCM Plans"
Click "here" under RCM Plans page
Click "View by Catagory"
Click Power Boat
Click PL-993 "POHO"

Weird name but a cute boat, I have ordered plans and expect it to be
my first RC PaddleWheeler.