Welcome to spira international home-built boat plans. 13′ lightweight duck boat; 11′ ultralight stitch and glue boat;. Free plans for stitch and glue boatbuilding. many good free plywood contruction stitch and glue boat plan. stitch and glue plans are built boats. duck punters. Spira international wooden boat plans. larger stitch & glue boats: 13′ marsh rat mini duck boat 16′ rail bird poling skiff.