Navy

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

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.

A neon green stripe on his sonar screen indicated that the Shang was only a few thousand yards off the U.S. sub's bow.

"Sonar contact!" he yelled to 15 officers and crew in the dimly lighted control room. "All stations, analyze!"

Within seconds, the 377-foot-long Mississippi banked right and gunned its nuclear-powered propulsion system for one of the Navy's most difficult maneuvers: sneaking up behind another submarine and shadowing it without being detected.