Bruce roberts official web site powerboat plans power boat kits for steel boats or aluminum boat designs, cut to size boat kits, part built boats or complete boats.. 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..