The Chinese Navy is making growing investments in unmanned surface and underwater systems, aka “drones.” They are experimenting in building autonomous UUVs of all shapes and sizes, looking to make them work together with each other, and Chinese warships too. The China State Shipbuilding Corporation (CSSC), which builds virtually all Chinese Navy warships, has proposed an “Underwater Great Wall” of sensors, positioned on the seabed floor, to listen for enemy submarines.