The Republic of the Marshall Islands (RMI) Maritime Administrator has awarded an Approval in Principle (AiP) to Anemoi Marine Technologies (Anemoi) for their Rotor Sail systems following a review of two bespoke configurations of the wind-propulsion technology.

Rotor Sails, also known as “Flettner” rotors, are vertical cylinders that harness the renewable power of the wind to provide additional forward thrust to the vessel and thereby improves its energy efficiency, along with a reduction in carbon emissions.

The RMI Maritime Administrator’s AiP was issued after undertaking a comprehensive review of a 210,000 deadweight ton (DWT) Newcastlemax bulk carrier designed by Shanghai Merchant Ship Design & Research Institute (SDARI), thereby validating Anemoi’s four Rotor Sails (measuring 5 meters (m) x 35 m) with a folding deployment system and six Rotor Sails (measuring 5 m x 30 m) with a bespoke rail deployment system.

The review also included a technical assessment of how the installation of Rotor Sails in both configurations will impact the vessel’s Energy Efficiency Design Index (EEDI) calculations, with an estimated improvement of 20% for the rail system and 17% for the folding deployment system for the vessel’s EEDI.

Anemoi Rotor Sails have been installed on board a number of RMI flagged vessels. Installation of Anemoi’s rail deployment system was completed in June 2023 on the 82,000 DWT TR Lady Kamsarmax bulk carrier. The 400,000 DWT Sohar Max very large ore carrier is scheduled for completion in mid-2024 with Anemoi’s folding deployment system. The Rotor Sails on both of these vessels will provide additional forward thrust, improve their energy efficiency, and reduce their total carbon footprint.

Ship owners are increasingly turning to Rotor Sails as an energy saving technology to ensure their vessels meet critical international emission reduction targets, including EEDI/Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII). The installation of three Anemoi Rotor Sails on board TR Lady is expected to save more than 10% on fuel and emissions annually, while the inclusion of Rotor Sails onboard Sohar Max is expected to reduce CO₂ equivalent emissions by up to 3,000 tonnes per year.