Pedal Boat - By John Rogers. This streamlined pedal boat skims the water on a foot power engin not as fast as horsepower, but a lot cheaper. Its payload: one youngster. Its size: less than five feet long and only 48 pounds overall. It even boasts power brakes (just back pedal) and a full reverse shift (back pedal harder). Ready made water bikes costs can get very high, but you can build this one for the price of a piece of plywood and some standard bicycle parts. If a lake or ocean isn't handy, it's small and light enough to run in a swimming pool, stream or the nearest duck pond. The one piece hydroplane style hull looks sharp and is easy to build.