Shipping giant Maersk is trialling a rotor sail from British company Anemoi Marine Technologies on one of its container ships, as the industry looks for ways to cut fuel use and greenhouse gas emissions. The device will be fitted to the Maersk Labrea, an 8,700 TEU Lima-class vessel, with installation scheduled for mid-2027 followed by testing on regular North and South Atlantic routes. The move comes as the International Maritime Organization pushes shipping firms to slash emissions substantially over the coming decades.

Rotor sails, also known as Flettner rotors, work very differently from traditional sails, using the Magnus effect: a spinning cylinder moving through the air generates a pressure difference that produces thrust, easing the load on a ship's engines. Anemoi will design and build a sail measuring 5 metres in diameter and 35 metres high, and provide engineering support to integrate it with the vessel's systems. The company says ships fitted with three of its rotor sails have achieved average net fuel and emissions savings of 9.1%, rising to as much as 21% on some voyages. The IMO wants the sector to cut emissions by at least 20% (versus 2008 levels) by 2030, 70% by 2040, and reach net zero around 2050.