It's quite rigid I think (purchased from DRMarine last year).
I did this job on my O'day 25. The biggest mistake I made was leaving the rigid rub rail coiled in the shipping box for about 6 months. The rail took a set in the coiled position. It was impossible to straighten out.
I had to wait until warm weather, find a vacant dock and stretch out the rub rail and screw it down to the dock and let it sit for several weeks in the sun until it straightened out.
While waiting I filled all of the old screw hole with thickened epoxy. I then went back and pulled out every other deck to hull joint screw, put a dab of 3M4200 on the screw and put them back in. Then I went around the hull and did the remaining screws.
By the the time the rigid rail had straightened I was out of time and had the yard install the rest.
Doing all this work did solve a lot of water leaks I had around the hull so the work was worth it.