Swimming in the lake is an essential part of the cottage experience but the brothers need a swim raft….the ultimate swim raft. Andrew and Kevin retreat to the drawing board eager to fix the situation. They quickly come to the conclusion that their new swim raft will need to be self-propelled so that it can be moored both at the shore as well as in the middle of the lake where the swimming is prime. Together with their engineer pal Walker, the boys decide to build the Ultimate Swim Raft, complete with benches, a cedar pergola, a hammock, a solar-powered motor, a trap-door cooler, a retractable anchor.