If you’re looking for high quality boat plans and tutorials with easy-to-follow instructions that guide you through the entire boat building process without emptying. 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. We have power boat building designs of all types such as power cats, cruisers, and more. view jon boat deck plans & boat cabin plans for more details..