Not to mention the Soviet Navy tried that whole sodium cooling system in such boats as the alpha and that turned out to be a blunder. I do happen to know some specifics (obviously can't discuss them) but the main thing is that the Seawolf was a good design in theory and on paper but was built a bit late in the game for what she was designed for. They did however take the lessons learned from Seawolf design and construction and applied them when they built Virginia...I think over the next few years you will see that she is a good class as well.
