Prior to removal, my portholes were originally screwed into the fiberglass hull from the inside. My plan is to re-attach by bolting through the hulll from the outside with the bolt head and washer resting directly on the fiberglass (with the appropriate sealant).
Does anyone see any problems with this installation other than drilling 40 holes in my boat? Why were they secured from the inside with screws in the first place? That seems like a really weak installation as a force from the outside could (and did) easily push the porthole in.