Since the early 1990s, at least 60 “drug subs” have been captured. They’re sophisticated contraptions, with multiple crew members and GPS navigation—and their sole purpose is to sneak massive amounts of cocaine, heroin, and other illegal drugs into the country. They’re exceptionally good at their job. To combat this menace, Boston University engineering professor Greg McDaniel is building a swarm of autonomous microboats. These machines would travel around an area of open ocean independently, listening for suspicious sounds. If an individual drone hears a noise, it can alert its robotic colleagues and invite them to collectively hone in on a target. This research, supported by the Naval Engineering Education Consortium (NEEC) and the Naval Undersea Warfare Center (NUWC) Newport, could help detect narco-subs and other small underwater threats more reliably—making the concept particularly attractive to the US Navy.