RE: Pontoon Boat and trailer 1:10 scale
Back in 1993 Andy Zigan came out with plans for a 1/8 scale R/C model of a 24' Pontoon boat and used an MRP outboard for power. The pontoons were made of 3" Irrigation pipe and turned wood plugs for the front and rear of the pontoons.
I happen to have the plans but never got around to building one of the pontoon boats.