: And when I build another one I will do as you did Rehd.

Adding internal bracing (rectangular pieces perpendiular to the lenght) every 2' is a must to prevent racking/ flexing. You can see Rehd did this in his strongback picture in his post, "Probably a Do-Over".

I like a bullet proof SB myself. You can see an example of my SB in Steve's picture post, "North Star 2nd Fill Coat".

I use an extenal, full lenght SB so I can lock the stems in place. I use the cheapest CDX 1/2" plywood and just cut a 4' X 8' sheet into 6" widths, make 8' real box beams (not the open bottom like Ted Moores) with internal bracing every 2'. The CDX plywood (exterior cheap) is never flat but once I assemble the pieces they cancel each other out.

Because I make a variety of lenght boats I have beam sections in different lenghts, 4', 5', 6', and 8's. I join the sections with an internal nesting 4' section and sheet rock screws. All my box beams are just screwed together on the edges.

I've used the same box beams for over ten years and they're still solid as a rock.

Rob