Build a flat bottom jon boat plans . these plans are to build a flat bottom fishing jon boat. fisherman who like to work the shallow backwaters and weed patches on lakes and rivers will find this flat-bottom scow-type boat an ideal craft.. Factor in building material and weight when selecting plans to build a fast flat bottom boat. while aluminum and fiberglass are the lightest materials, equating to greater speed potential, they are also the most expensive, and potentially more difficult to work with because it requires welding, molding and shaping skills.. The alumacraft 14′ flat-bottom jon boat features a 1-piece hull and 6 extra-wide ribs..