A few of my port holes are crazed like the one in the image. Is there a way to clear that condition or does it need to be replaced? If replacement is the course where would I find something like that? It is ~16" wide by 5.5" tall.
Look at the porthole, is the glass removable from the framework? Next option would be to replace the complete porthole.
I just did my TaylorMade vents two 12x12’s. I ordered the lexan fro eplastic, cut them to fit and installed. You may want to see if that is in your scope of work