The SB Met, built by Norwegian company Offshore Sensing AS, reached the finish line of the Microtransat Challenge for robotic boats on Aug. 26, two and a half months after setting off from Newfoundland, according to preliminary data.

It's a milestone that shows the technology for unmanned boats is robust enough to carry out extended missions that can dramatically cut costs for ocean research, border security, and surveillance in rough or remote waters. They're part of wider efforts to develop autonomous marine vessels such as robotic ferries and cargo and container ships that could be operating by the end of the decade, outpacing attempts to commercialize self-driving cars.