Wind propulsion technology provider Norsepower has completed factory acceptance testing for 18 rotor sails destined for a new fleet of ro-ro vessels operated by French shipowner LD Armateurs.

According to the company, the final two Norsepower Rotor Sails for the vessel series completed factory acceptance testing on 1 April at Norsepower’s China factory. All units for the project have now passed pre-delivery testing and received on-site class certification from Bureau Veritas, clearing them for shipment.

The project marks the first cooperation between Norsepower and LD Armateurs, together with Airbus, and will see 18 rotor sails installed across three new-generation low-emission ro-ro vessels.

With six rotor sails fitted on each vessel, the series is expected to represent the largest number of mechanical sails ever installed on a single ro-ro ship.

Norsepower said the fleet is projected to achieve about 50% lower CO₂ emissions by 2030 compared with 2023.

The sails for the project will also be equipped with the Norsepower Sentient Control system, which uses machine learning algorithms and real-time force measurement to optimise sail operation and improve aerodynamic efficiency.

Installation of the first rotor sails is due to begin later this year at Wuchang Shipbuilding Industry Co., Ltd. in China.

Rotor sails operate on the Magnus effect, where rotating cylinders create aerodynamic lift when exposed to wind, providing auxiliary propulsion that reduces main engine load and fuel consumption.