Sponson Sides

This is a pretty straight-forward operation. If you have enough clamps, you can install the sponson sides with only a few screws.

Once you have cut the first piece to size (leaving some extra for trimming after it's installed), clamp it in place and then drive in 3 or 4 screws, say at frames 2, 3 and 4. These will allow you to quickly get the piece back in its proper location during final installation.

After the glue has dried, plane the plywood flush with the chine.

Spray Rails

Spray rails are located 1.5 inches above the chine, and extend forward almost to frame 2. You can make it longer if you like, but this seemed long enough to me. Install with screws driven from inside the sponson, except at the transom where you will go the other way.

I also added a carriage bolt at the forward end -- the rail is just starting to go around the curve of the boat and so seems under particular stress here. They started to separate on my last boat.