An enormous ore carrier has become the largest vessel yet to harness the wind, another baby step in the industry’s efforts to cut its fuel bills and carbon emissions.

The Sohar Max — with a capacity of 400,000 deadweight tons — recently had five, 35-meter-high rotor sails retrofitted at the COSCO Zhoushan shipyard in China. They’re expected to be able to cut the vessel’s fuel consumption by as much as 6%, and carbon emissions by up to 3,000 tons a year.

“There’s definitely an uptick in the adoption of wind propulsion and not just rotor sails, but other technologies too,” said Nick Contopoulos, chief production and partnerships officer at Anemoi Marine Technologies, which produced the sails.

Shipping is under regulatory pressure to cut emissions, with some rules already in force and others in the pipeline. Rotor sails are still relatively rare for vessels, and the success of wind technologies in general will ultimately depend on whether they’re able to save shippers money. The business case is likely to significantly improve if shippers are forced to move away from oil to cleaner — though more expensive — alternative marine fuels.