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. 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.. All power boats 16′ long and under. tech support. the best technical support: we will help you succeed! all our plans and kits come with full technical support..