Autonomous sailing robot completes Atlantic crossing after 127 days
A 1.2-metre autonomous sailing robot has crossed the Atlantic without human intervention, completing a 127-day voyage that tested its navigation, power management and ability to operate independently in open ocean.
C-Star PC13, developed by UK maritime technology company Oshen, crossed the finish line east of Barbados at 09:56 UTC on 13 September. It had departed Gran Canaria on 7 May and travelled 2,926 nautical miles (5,400km), navigating trade winds and busy shipping lanes.
The voyage won the Microtransat Challenge, a competition for autonomous boats in which vessels must cross the Atlantic without assistance. Once launched, teams cannot influence the boat’s decisions or change its course.
The rules also limit boats to 2.4 metres in length. The size restriction reduces the available area for solar panels, placing limits on the energy available for onboard computing and other systems.
PC13 uses autonomous navigation software developed by Oshen to continually assess factors including wind speed and direction, ocean currents and battery levels. The system can use that information to determine whether to hold position or sail towards a pre-selected destination.
Developing a system capable of operating for months without intervention has required multiple sea trials. An earlier attempt in 2023 ended after 20 days and 10km. In 2025, a modified boat launched from Plymouth spent 277 days at sea and travelled about three-quarters of the way across the Atlantic before losing its sail in heavy seas.
The vessels are also designed to collect environmental data. C-Stars can record up to two million data points a day, measuring variables including sea-surface temperature, air temperature, pressure, humidity, salinity and water density.
The technology was also tested in extreme conditions in 2025, when another C-Star entered the eyewall of Category 5 Hurricane Humberto. It survived waves reaching 10 metres and winds exceeding 240km/h while transmitting data.
PC13 encountered a developing low-pressure system associated with Storm Dolly during its crossing, but did not encounter a hurricane.
“We are thrilled to have finally completed the Microtransat,” said Anahita Laverack, Oshen CEO and co-founder. “Even in the final hours, after so many days at sea, we weren’t certain that PC13 would reach the designated finishing zone.”
