In 2010, the Defense Advanced Research Projects Agency, or DARPA, announced that they were building a 132-foot autonomous boat to track quiet, diesel-powered submarines. The program was dubbed Anti-submarine Warfare Continuous Trail Unmanned Vessel, or ACTUV.

To little notice, the system earlier this year passed a critical test, moving much closer to actual deployment and potentially changing not just naval warfare but also the way humans, ships, and robotic systems interact across the world's waters.

In six weeks of tests along a 35-nautical-mile stretch of water off of Mississippi, testers at engineering company Leidos and DARPA put the ACTUV's systems through 100 different scenarios. The test boat, equipped with nothing more than off-the-shelf radar components, a digital area chart and some proprietary software, was able to complete an autonomous trip without crashing into rocks, shoals, or erratically behaving surface vessels. In future tests, the ship will tail a target boat at one kilometer's distance.

Most importantly, the tests showed that the robot boat could execute a difficult military mission without violating the maritime laws outlined in the Convention on the International Regulations for Preventing Collisions at Sea. They also provided a critical proof-of-concept for machine-learning systems at sea, showing that big robots can, indeed, navigate the open seas along with cruise ships and shrimp boats.