The U.S. Navy submarine admirals are being less silent about operations against China than they were about the covert operations against the Russians during the Cold War. In the 1990s the U.S. allowed some details of these submarine espionage operations to go public and it turned out they were very important, especially since the Russians never caught on. Now that everyone knows about that the American submarine community is being rather more open about what (in general) current plans mean for China.
One tactic involves U.S. nuclear subs carrying a dozen or more torpedo sized UUVs (unmanned underwater vehicle) to be launched from torpedo tubes (and sometimes recovered for reuse as well) to perform electronic warfare (mostly jamming) and reconnaissance (electronic and the more conventional forms). The advantage of this approach is that the sub can launch these devices then quietly move away while some UUVs jam enemy sensors for a while then, before the Chinese can pinpoint their location and attack, switch off and silently move away. The UUVs can, when finished, go to a prearranged location and wait underwater until the sub comes by to pick them up. The subs can also release buoys that rise to the surface and listen or jam. For the listening devices the sub comes by after a while and collects the data. These buoys can also be used to send data collected back to navy headquarters via encrypted satellite link. That will enable the Chinese to spot them but the buoys can either self-destruct or simply sink in deep water. The navy has also tested UAVs launched from torpedo tubes, for reconnaissance or jamming.
This submarine based electronic warfare and reconnaissance effort is nothing new. A decade ago it was known that the U.S. Navy was very interested in UUVs and some of these ideas can be traced back to the 1990s or earlier. It was often a matter of waiting for the tech to catch up with the ideas. News of some of the development work has been released.
For example, back in 2007 it was announced when an American sub made its first successful launch and recovery of a UUV while submerged. The UUV was an AN/BLQ-11 long-term mine reconnaissance system (LMRS), which contained sonars that enabled it to search for naval mines, or anything else. In effect the LMRS can scout ahead for the SSN, or simply search an area. The LMRS is about the size of a torpedo, and is launched and recovered via a torpedo tube. It is then recovered via an 18.5 meter (60 foot) robotic arm. This system worked the first time out, and the process was repeated two days later. The UUV was designed to be used on Los Angeles and Virginian class subs.
The LMRS can operate for 40 hours, and up to 135 (eventually over 200) kilometers from the submarine. Cruising speed is about 7 kilometers an hour, with a top speed of 12 kilometers an hour. It can operate from 3 to 61.5 meters (ten to 200 feet) beneath the surface. In addition to GPS, the LMRS has side scan sonar, forward-looking sonar, hunting and docking sonar, acoustic communications and range pingers. The UUV is battery powered and uses a thrust-vectored pumpjet for movement and maneuvering. Previous UUVs were wire (fiber optic cable) controlled, while LMRS can carry out missions by itself. Each LMRS (two UUVs, the recovery arm, and other gear) costs over $100 million. At the time the navy planned to buy about a dozen systems. This, it turned out, was only one of many UUV designs for submarines. Details on most of the other ones were apparently kept secret.