Added Strength Under Cap

[crsavage1]

I am interested to see what advice you get. Have a similar issue where my cap needs some added strength in the corners. I have included the underside of mine which is in the aft corners where my enclosed transom is. Curious if yours look anything like this?

For reference, this is a picture of the underside of my cap. This is the corner of the transom and port side with the open hole being one of the thru-hulls that I took out. There is serious spider cracking in the corners that will need ground out and fixed, but I think the real issue is the lack of support for the cap in the first place.