Instant access to 518 different plans – from small wooden boat plans to large sailboat plans – free boat plans. 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 designs that are simple to build, rugged and seaworthy.. Boat plans for power, sail and small boats. free boat plans. boat kits and supplies plus the best boat building technical support..