Aboard a U.S. nuclear sub, a cat-and-mouse game with phantom foes

Los Angeles Times – America’s most advanced nuclear submarine was slicing through the water off Hawaii last month, 400 feet under the surface, when a sonar operator suddenly detected an ominous noise on his headphones. It was a faint thump … thump … thump — the distinctive sound of a spinning, seven-bladed propeller on a Chinese attack submarine called a Shang by the Pentagon and its allies.