Hi George,
I made calculations for hull stiffness, based on frame/stringer spacing and hull thickness. According to those calculations (with my stiffener location which is not the same as stock SC), the center stringer was not required.
I made the PVC pipe center stringer to provide a little stiffness, plus its a drainage to the bilge for the rest of the compartments. Its made from a 4" piece of drain field PVC (light weight), its then covered in two layers of 1708. My project hull did not have a liner.
I added frames to my boat, between the stringers, which adds a lot of stiffness. If I had replaced the original liner, I would not have been able to fit in the frames. In that case I would have definitely replaced the center stringer as original. Hope that helps
BTW, something is wrong with my image tags in the above post, i tried several different ways to do it, but no luck. Im a little new to this thread posting thing, so maybe I will figure it out
