Rotor Sails Set to Revolutionize MR Tankers in Bold Green Shipping Push

How Anemoi, Hafnia, and GSI Are Betting on Wind Power to Slash Emissions

The shipping industry’s race to decarbonize has taken a turn toward the past—with a high-tech twist. Anemoi Marine Technologies, Hafnia, Guangzhou Shipyard International (GSI), and DNV are collaborating to retrofit 50,000 dwt MR tankers with rotor sails, a century-old concept reengineered for the age of carbon accountability. The joint development project (JDP), signed in late 2023, aims to create scalable designs that could cut fuel consumption by up to 30% on select routes. “This isn’t just about compliance; it’s about reimagining propulsion,” says a Hafnia spokesperson.

“Rotor sails are the low-hanging fruit of maritime decarbonization—simple physics, immediate impact.” — Anemoi engineer

At the heart of the project are Anemoi’s vertical cylindrical sails, which harness wind energy via the Magnus effect. The JDP will focus on optimizing installation layouts for MR tankers, including electrical integration and control systems. Hafnia and Anemoi will lead engineering studies to quantify EEDI and EEXI improvements, while GSI handles naval architecture and technical documentation. DNV’s role as independent verifier through an Approval in Principle (AiP) assessment adds crucial industry validation. “The MR segment is ideal for this tech—their trading patterns match wind-optimized routes,” notes a DNV representative.

Hafnia’s Green Gambit

For Hafnia, the rotor sail initiative dovetails with its aggressive decarbonization strategy. The company made waves in 2023 by ordering dual-fuel methanol MR tankers from GSI and acquiring the 49,800 dwt Ecomar Gascogne, a vessel already equipped with energy-saving features. Rotor sails—specifically Anemoi’s tiltable Wind Assisted Propulsion System (WAPS)—offer a complementary solution. “Methanol solves the fuel question; wind solves the consumption question,” explains a Hafnia project lead. Early estimates suggest the systems could pay for themselves within five years at current fuel prices.

The industry is watching closely. MR tankers account for nearly 40% of the global product tanker fleet, and their mid-size profile makes them prime candidates for rotor sail retrofits. With IMO’s tightening EEXI and CII regulations, the pressure is on. “This partnership proves wind assistance isn’t just for niche operators anymore,” argues an Anemoi executive. As the JDP progresses toward 2024 sea trials, one thing is clear: the age of fossil-fuel-only propulsion is ending—one spinning cylinder at a time.