If the high cost of factory-built flats boats is crimping your fishing style, then build our flats flyer. you’ll get a flats boat exactly the way you want it at a. Manufacturer of shallow water, catamaran flats boat with hand laminated fiberglass hull, patented catamaran design, and self bailing. located in rosenberg, texas.. Welcome to spira international home-built boat plans. spira international offers a wide variety of different power, rowing, and sailing skiffs, dories, and other boat.