Anemoi awarded DNV Type Approval for 5x35m rotor sail design

Anemoi Marine Technologies Ltd (“Anemoi”), a leader in wind-assisted propulsion systems, was awarded a Type Approval Design Certificate from classification society DNV for its Rotor Sail design measuring 5 metres in diameter and 35 metres in height.

The Type Approval Design Certificate (TADC) was retrospectively presented to Anemoi during a special ceremony at SMM in Hamburg, Germany, on 5 September 2024. The certificate validates that Anemoi's 5x35m Rotor Sail design complies with DNV's technical standard (ST-0511) for Wind Assisted Propulsion Systems (WAPS) .

Kim Diederichsen, CEO of Anemoi, said: "We are delighted to have received this important Type Approval from DNV, which is a testament to the rigorous design and engineering work undertaken by our team. 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."

Hasso Hoffmeister, Senior Principal Engineer at DNV Maritime: “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.”

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.

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 capitalise on the aerodynamic phenomenon known as the Magnus Effect to provide additional thrust to vessels. By leveraging wind energy, Berge Neblina will see increased efficiency by reducing the power required from the main engine while maintaining speed, therefore substantially reducing fuel consumption and resulting in less greenhouse gas emissions.

The technology is being increasingly embraced by ship owners, primarily in the bulker and tanker sectors, who are aiming to achieve net-zero shipping emissions. Rotor Sails have emerged as a preferred technology to augment and enhance the energy performance of vessels. Rotor Sails are a compact technology, which offer a large thrust force to propel ships with minimal impact on visibility, stability and port operations, helping them comply with pivotal international emission reduction benchmarks such as the Carbon Intensity Indicator (CII) and EEDI/EEXI.