Maersk Is Putting a 115-Foot Sail on a Container Ship
Maersk has signed a deal to install a rotor sail on one of its container vessels, marking the carrier’s first move into wind-assisted propulsion for its ocean fleet. The 115-foot-tall unit, designed by London-based Anemoi Marine Technologies, will be retrofitted onto a 984-foot, 8,700-TEU Lima-class ship, with installation due in mid-2027. The vessel is expected to operate on Maersk’s north and south Atlantic voyages while the sail is piloted, with the system then tested in commercial service.
Rotor sails are tall, spinning cylinders that harness wind to supplement engine power. Here’s the scale of the bet: Anemoi typically installs three to five of them per vessel and says each unit saves roughly one ton of fuel per day, cutting about three tons of CO2 emissions. Maersk is starting with one sail on one ship: a measured trial rather than a fleet rollout.
The sail fits into a broader, fuel-agnostic efficiency strategy at Maersk. In 2025, the carrier added 10 dual-fuel methanol vessels and completed fuel-saving retrofits on 230 owned ships and 150 time-chartered vessels. That work pushed its ocean Energy Efficiency Operational Indicator to a record low of 10.8 grams of CO2e per ton-nautical mile. By 2027, Maersk expects 25 dual-fuel ships in service, with a longer-term target of 25% of its fleet capable of running on lower-emission fuels. The stated end goal: net-zero emissions by 2040.
Maersk isn’t the only carrier testing wind. Earlier this year, CMA CGM began rotations of the sail-assisted Neoliner Origin, a ro-ro vessel calling the Port of Baltimore. Wind assist is moving from concept to commercial service.
What does this mean for your operations? Not much yet. This is a carrier-side efficiency pilot, one sail on one ship, with installation due in mid-2027 and commercial testing to follow. The bigger signal is the pattern. Maersk isn’t alone: CMA CGM’s sail-assisted vessel is already in rotation, and Maersk’s own pilot follows in 2027, on top of its dual-fuel fleet and fuel-saving retrofits. The EEOI figure Maersk reports, a measure of CO2-equivalent emissions per ton of cargo moved one nautical mile, is the kind of carrier-level data worth knowing when you compare ocean partners.
For now, file this under watch and wait. The real story arrives once the sail has some Atlantic crossings behind it.