This is not the only occurrence. Another boat had a similar problem, though not as lengthy. I don't recall if it penetrated all the way through. This area is a casting that is welded into the hull plating. Had to pass wicked tough NDT as it is SubSafe stuff. This may be a case of fatigue due to work hardening or such. The casting contains the 'scope penetrations.
Watched the boys in the yard lift off USS Hartford's sail today. Pretty neat!
"If you ignore the problem long enough, it will go away. Even flooding stops eventually!"