Rubrail extrusion
You didn't specify the aluminum or rubber extrusion, I'm assuming you are talking about the aluminum. I replaced both on my '72 27. After trying various ways, I cut the aluminum at the bow, and just worked the rubber in. Before I cut it, I tried what was recommended by the yard.They said to mount (screw it in) a few feet before the bend and force it around, fastening each screw as I worked it. This I found impossible to do without damaging the extrusion. I finally gave up and cut it. It worked fine, and one wouldn't know it was cut without looking.As an aside, that was the easy part. Fitting the rubber in was tedious and time consuming. Heat, and soapy water really helped.I was very pleased with the end result..did a lot for the overall appearence of the boat. Good luck.