The whole thing was made pretty much with what we had laying around. The engine was a 5 HP B&S engine. It doesn't take much power, so you don't have to build stuff like a tank. The arms were something like 3x4" and I just bolted them to the side of the hull. The two sides of the wheels were 1x1" steel tubing. The wheel diameter was 4' and pretty close to 4' long. I drew the layout on a piece of plywood, cut the tubing and clamped it to the ply. Tack weld one side, flop it over and weld the other side and then flop it back and finish welding the first side. I welded the ends to a piece of pipe that had a 1" inner diameter. I drilled some holes in the pipe and then put a 1" steel shaft through the pipe, and that was supported by the bearings. I welded the pipe to the shaft through the holes I had drilled in the pipe. That kept the shaft all straight and true without warping it by too much welding. The paddle blades were 1x6" treated decking. We had a dock that we kept it at and a problem that develops with wood paddles is a few sit in the water all the time and get heavy with water and then the wheel gets out of balance. Paddlewheelers are always coping with too much weight in the stern, so keep that in mind.