An autonomous, underwater military system is the goal of DARPA in this age when figurative piracy hasn’t complete replaced the literal kind. From Wired:

“DARPA, the Pentagon’s research agency, has recently revealed its plans to boost the Navy’s response to threats in international waters by developing submerged unmanned platforms that can be deployed at a moment’s notice.

Hydra, named after the serpent-like creature with many heads in Greek mythology, would create an undersea network of unmanned payloads and platforms to increase the capability and speed the response to threats like piracy, the rising number of ungoverned states, and sophisticated defenses at a time when the Pentagon is forced to make budget cuts. According to DARPA, the Hydra system ‘represents a cost effective way to add undersea capacity that can be tailored to support each mission’ that would still allow the Navy to conduct special operations and contingency missions. In other words, the decreasing number of naval vessels can only be in one place at a time.”