What technology has the U.S. Defense Advanced Research Projects Agency proposed to fight terrorists and pirates?

A new network of unmanned vehicles in the air, on and below the water would give the military the flexibility and speed to monitor large reaches of sea with the option to respond quickly if necessary. The project, called Hydra, would include construction of underwater shelters housing drones equipped with sensors and communications equipment. When called upon, the underwater drones would leave their shelters and continue on to their missions, whether below or above water.