Find a variety of fishing boat design plans for all power boats 16′ long and under. our power boat building plans make it very easy to construct your own!. This boat is easy to build using our downloadable boat plans. our boat plans are available for instant download so you can start building right away.. 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.