And fix it they did, apparently. Ummm because I've participated in exercises with them, and been onboard them while they submerged? USS Cheyenne is the newest Los Angeles class attack sub. I've been on/exercised with at least three other LA boats, and they were definitely submerged. Perhaps you should aim for a little perspective, that some problem you heard about with a single submarine that made it non-diveworthy is considerably different than a fleet of submarines that have systemic maintenance and reliability problems. The US hasn't lost a submarine since 1968, the Russians have lost three since then and had numerous other problems. Sure, but anecdotes =/= truth.