I removed the nuts from the studs inside the hull
, moved the copper strapping out of the way and realized that there was not much separating the water
from the inside...
There was, however, a neat trick used when these were originally mounted. A nylon or marelon bushing fit over the bolts on the inside of the hull. They applied a sealant
underneath this bushing and then tightened the nut. When I pulled this off, I had a gasket
formed of 4200 underneath this bushing. There is a trademark name "Wonderseal" on these and I guess they're made specifically for this purpose. I show two of them, the one on the right is inverted to show the groove where the sealant
forms its own o-ring around the bolt.
After pulling these off, I was able to tap the bolts out / down with a hammer. Came out extremely easy.
So all that remained between the ocean and the people tank was the bushing and a caulking seal.... how comforting!