The Wind-Powered Future of Tankers: How Rotor Sails Are Revolutionizing MR Fleets

Harnessing the Wind for a Greener Shipping Industry

In a bold move to slash emissions, Anemoi Marine Technologies, Hafnia, GSI, and DNV have joined forces to design rotor sails for 50,000 dwt MR tankers. This collaboration marks a significant step toward decarbonizing the shipping sector, leveraging an old concept with modern engineering. The joint development project (JDP), recently signed, aims to create eco-friendly rotor sail designs tailored to enhance the efficiency of medium-range tankers. If successful, this could set a new standard for wind-assisted propulsion in commercial shipping.

“Rotor sails represent a pragmatic yet transformative solution—bridging the gap between fossil fuels and zero-emission futures,” says a Hafnia spokesperson.

Engineering the Details

The project will kick off with rigorous engineering studies to evaluate rotor sail installation, electrical systems integration, and their impact on key regulatory metrics like EEDI (Energy Efficiency Design Index) and EEXI (Energy Efficiency Existing Ship Index). GSI, a key player in tanker construction, will handle technical documentation, while DNV brings its expertise to the table with an Approval in Principle (AiP) assessment to verify the design’s feasibility. This meticulous approach ensures the technology meets both performance and safety benchmarks before hitting the open seas.

Hafnia’s Decarbonization Push

For Hafnia, the initiative aligns with its broader strategy to cut emissions and improve fuel efficiency. The company has already made waves with its 2023 order of dual-fuel methanol MR tankers from GSI and the recent addition of the 49,800 dwt Ecomar Gascogne to its fleet. Rotor sails—also known as Flettner rotors—could further solidify Hafnia’s position as a sustainability leader. These cylindrical structures harness wind power to generate additional thrust, reducing reliance on traditional fuels and slashing CO2 output by up to 30% in optimal conditions.

“Wind-assisted propulsion isn’t just a backup plan; it’s a cost-effective bridge to a cleaner industry,” notes a DNV engineer.

The Rise of Rotor Sails

Once a niche technology, rotor sails are gaining traction as a practical, scalable solution for emissions reduction. Their ability to integrate with existing vessels—without requiring a full retrofit—makes them an attractive option for shipowners eyeing compliance with tightening environmental regulations. As the JDP progresses, the maritime world will be watching closely. If Hafnia’s bet pays off, rotor sails could soon become a common sight on tankers worldwide, proving that sometimes, the oldest energy source—wind—holds the key to a greener future.