Articles, columns, and homebuilding projects. by and for backyard boat builders.. 9 . 9 cartopper 9; airolite; skin on frame plans; geodesic airolite boat designs. 9 explorer; ken simpson; paddle or row; ply plans. Updated: march 12, 2017. added the arrow to the new design idea page. added the simple duckboat to the plans page. (free) thank you for your interest in my portable.