Bolt-On Chine

The design of spray rails is, like everything else, a subject in its own right.
People get PhDs and publish professional papers on these subjects.
I'm not one of them, but I have read enough to know that there are fast spray rails and slow spray rails. Since we are usually talking about motorboats, ones that save fuel and ones that don't.
Hobie Cat rolled lip hull deck joints are not designed as spray rails. Rolled lips were developed as a cost effective way to assemble fiberglass boats with polyester based putty.
This stuff was pretty weak compared to "real glue" so you needed large bond areas to get adequate sheer properties. Thus the rolled lip hull deck joint.
They clearly knock the spray and water that run up the topsides away, but they most likely absorb more energy than they shed. If you took a Hobie cat and cut the rolled lips off and arranged to have a flush hull deck joint, the boat would be significantly faster.
SHC