Chinese submarines cruise South China Sea

（China Military Online）  08:47, January 25, 2013  

The depth sensor finally read 200 meters. Luo Zuyun, captain of the submarine, said that in this depth we could eliminate the threat from satellite-sounding and the natural noises of the sea with a positive sound velocity gradient could drown out those of the submarine, therefore, the submarine could remain undiscovered in the sea.

Upon its arrival at the predetermined sea area, the submarine started the drill of laying underwater mines. In recent years, the flotilla has completed actual-troop live-ammunition drills on such subjects as underwater torpedo salvo, underwater over-the-horizon missile attack, underwater concealed mining and blockade and great depth navigation, and joint military exercises on such important subjects as joint attack and joint blockade in cooperation with surface ships and aviation force.