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. Outboard runabouts, hydroplanes, and speedboat plans and kits for a variety of construction methods designed for the home boat builder.. Calmly float through the river with this sturdy, easy-to-build 12′ duck hunting jon boat. order plans and kits for this flat bottom garvey at bateau..