Wooden boat plans developed by a boat design expert & naval architect. all boat plans come with free 3-d computer models & free master boat builder course.. 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. Boat plans: boat plans from 36 designers and counting. sail, row, power, paddle—we are sure you will find the perfect boat..