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.. The 15′ row catamaran now comes with sail and rig details. so there are now three possible ways of propulsion: oars, outboard and sail. see 15′ row catamaran page for. Free plans: absolutely free plans (links to free online boat plans) ariawood boat works (plywood punts, jonboats and one-sheet boats) architectura navalis mercatoria.