Post #61
http://www.x-h2o.com/index.php?threads/my-1st-superjet.103772/page-4
"The overall sponsons is 14.5" x 1.25" measured by the area exposed under the bond rail." Same size as a SXR sponson.
I made a mistake when I made them so I had to drill a hole in my bond rail. I made them the right length to use the stock bond rail holes but then when I shaped the back of the fin it became too short. A rounded tail or a bit longer and I wouldn't have had to drill another hole. Be sure to measure your stock SXR holes if it has them so you don't have to drill.
These worked just fine on my superjet. They had some flex so aluminum would be better. I'd probably use something like 1/8" or 3/16". My glass ones were super thin. 3 layers of biax under 15 lbs compression. Steps are in the post.