DARPA, the organization used by the military to develop new technologies (from its website: to make pivotal investments in breakthrough technologies for national security.), recently released photos of an autonomous vessel that it built called the Anti-Submarine Warfare Continuous Trail Unmanned Vessl (or ACUVD). It is specifically designed to track diesel submarines.
Click here for the DARPA website that describes how it works.
Here is a time lapse of it under construction – it gives a hint as to what is inside.
https://www.youtube.com/watch?v=Xgef3jmeY_Q
Link up a few of these babies on SKYNET and we’re all set!