Smart ‘man overboard’ detection deployed on North Sea rig

An AI-powered system that can automatically detect and track persons overboard at sea has been deployed on an oil rig for the first time.


Developed by Edinburgh-based Zelim, Zoe is a person in water (PIW) detection system to aid search and rescue operations at sea. It uses a suite of cameras and sensors to monitor the area around a vessel, raising alerts if someone falls overboard. Once someone is in the sea, Zoe’s software can then track them with around 97 per cent accuracy to a distance of over 330m. According to Zelim, the system has been trained on a dataset of over 4.9 million maritime rescue images across a wide range of ocean conditions. 

Zoe was deployed on the jack-up rig Valaris Stavanger in February 2024. Zelim installed a tailored solution that includes seven infrared and optical cameras placed around the vessel, allowing the entire rig to be monitored. Following an initial trial period, Valaris will evaluate the suitability of the system for use on other assets in their fleet.

“The North Sea is a harsh weather environment that can change quickly,” said Glen Spearman, offshore installation manager onboard Valaris Stavanger.

“If someone ends up in the water, the alarm is raised and one person acts as a spotter to maintain visual contact. We are totally reliant on line of sight. Zoe gives us a 360-degree view from the rig at any one time. It could reduce our response time and improve the chances of successful rescue in the event of a person overboard.”

With Zoe, a PIW situation triggers an automatic alert to the radio operator, who can see a 10-second clip of when the alert was triggered whilst simultaneously viewing live footage. The system continues to track the PIW, increasing their chances of successful rescue. Zoe also logs the position of the vessel and the person overboard at the point of detection for mayday call geo-location, as well as providing the radio operator with a mayday script and actions checklist.

“Zoe has been designed and developed in collaboration with the US Coast Guard,” said Doug Lothian, chief technology officer at Zelim.

“The system has been through extensive testing in adverse conditions and given a 96.8 per cent successful detection rate up to 337 metres, which is above and beyond standard requirements. Valaris was involved with us on this project with hands-on experience of their work environment, which meant we quickly understood their specific customisation requirements.”

Alongside Zoe, Zelim is also developing hardware solutions to aid search and rescue operations, including a rescue ‘conveyor’ called Swift and an unmanned rescue vessel known as Guardian.