Portlights
I believe the ome was dow corning 795, a very tenacious silicone seal. Remove gently, and bring a razor blade to cut away the sealant that has not failed. Do NOT fight with this sealant, as you will break the parts. I believe that this material is available from Hunter Marine. Call them after the weather down there has stabilized,and I'm sure they can inform you as to tooling , cleanup, etc. Hope this helps, Jim