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. Boden boat plans professionally designed ocean proven. thousands of boden designs have been built from the stock plans available. many have completed world circum. Free plans: absolutely free plans (links to free online boat plans) ariawood boat works (plywood punts, jonboats and one-sheet boats) architectura navalis mercatoria.