through-hulls

Hello to all, My first post here. I am in the process of buying an old boat and it was hauled out of the water yesterday. Ive attached a couple of photos below of the hull which is going to be pressure washed today for a better view and for the surveyor to look at. There is a circular patch...

I've not found much previous online regarding my question... This has 3 through-hulls on each side of boat, one along the top of the fixed keel (facing out), and the other 2 up higher on the bottom of the body (facing down), but all UNDER the water line. As I've removed the old bilge pump and...