Shroud chain plates

Hi, one of the three screws attaching the port shroud chain plate to the hull of my Dart 20 no longer has anything to screw into inside the hull. I am planning on installing an inspection port so I can access the inside of the hull and make repairs. What would be a good location of the inspection port, for example, near the chain plate, or half way between the front beam and rear beams, or something else.
Thanks,
Dan