Wasn’t there a sub not long ago that ran into an underwater mountain and the Navy’s plans were to cut off the nose, and weld a new one into its place?
I think I’d have second thoughts about that around now.
The hull is cut up and rewelded all the time. Not a big deal.
That was the USS San Francisco. The problem is that the damage was not limited to the front section of the boat. The impact caused buckling along the entire hull, and the boat will probably be scrapped.