Anemoi Secures DNV’s Approval for Wind-Assisted Rotor Sail Design

Wind-assisted propulsion systems developer Anemoi Marine Technologies has secured a Type Approval Design Certificate from classification society DNV for its Rotor Sail design.

The Type Approval Design Certificate (TADC) validates that Anemoi's 5x35m Rotor Sail design complies with DNV's technical standard (ST-0511) for Wind Assisted Propulsion Systems (WAPS).

In May 2024, Anemoi's 5x35m Rotor Sail was installed on the DNV-classed bulk carrier Berge Neblina, owned by Berge Bulk, representing the first commercial deployment of this product size.

Anemoi has also previously obtained a full Statement of Design Appraisal for the 5x35m Rotor Sail, and has additional installations planned for later this year and into 2025, including on the Sohar Max, a 400,000 DWT VLOC operated by Vale.

"This certification provides shipowners and operators with the assurance they need to invest in our 5x35m Rotor Sail solution, which has already been selected for upcoming installations on several vessels,” said Kim Diederichsen, CEO of Anemoi.

“Over the last few years WAPS technologies have continued to go from strength to strength, with the number of installations tripling in just the last year according to estimates from the IWSA. This growth has been built on innovation, safety, and trusted expertise.

“We are very pleased to build on the excellent collaboration with Anemoi with the presentation of this certificate. Together we are continuing to develop the technical standards and class notations that will enable the momentum behind WAPS to continue to build and enhance shipping’s drive to greater sustainability,” added Hasso Hoffmeister, Senior Principal Engineer at DNV Maritime.

Rotor Sails, also referred to as ‘Flettner Rotors’, are vertical cylinders that, when driven to rotate, harness the renewable power of the wind to propel ships.

These highly efficient mechanical sails capitalize on the aerodynamic phenomenon known as the Magnus Effect to provide additional thrust to vessels.