Currently, skilled contractors are replacing all seacocks and thru hulls. Once the thru hulls were removed they determined that the caulking used 35 years ago had long since passed its servicable life span, and water had seeped into the fiberglass core surrounding these holes. During removal of these thru hulls, some of them basically fell out once unbolted. Fortunately we decided to go ahead with this project.
Right now these holes in our boat are being cut larger to remove any softened glass, new mat is being epoxied in, and brand new holes, drilled. Some of them, since there were 9 total, have been left glassed over to reduce the number of holes in the boat. Our third bathroom was converted into a walk in closet space so the holes for that are no longer needed. And while writing this I sent a text to our boat guy to check our transducers as well. Probably have to replace those to be safe.