Anemoi Marine Technologies Ltd, an industry leader in wind-assisted propulsion systems, has announced that it is collaborating with Hafnia Limited, Guangzhou Shipyard International (GSI), and DNV to develop the integration design of Rotor Sails suitable for installation on 50,000 dwt Medium-Range (MR) tanker vessels.
The companies signed a Joint Development Project (JDP) in April 2025 to develop a new generation of efficient and environmentally friendly Rotor Sail vessel designs to increase the efficiency of MR tankers within the wider global fleet.
As part of the project, Anemoi and Hafnia will undertake several engineering studies to establish specifications related to how Rotor Sails can be safely and efficiently installed on the deck of MR tankers, alongside additional electrical and control system layouts for these vessels. In addition, the studies will include calculations to examine how Rotor Sails can improve the Energy Efficiency Design Index (EEDI) and Energy Efficiency Existing Ship Index (EEXI) values of existing and future MR tankers.
GSI will apply its naval architecture and marine engineering principles to develop essential technical documentation for the new Rotor Sail’s design integration, while DNV will undertake an Approval in Principle (AiP) assessment to ensure that the design is feasible and verifies that no significant obstacles exist to prevent the design from being realized based on current and foreseeable regulatory and class requirements.
Rotor Sails, also known as ‘Flettner Rotors’, are vertical cylinders that harness the renewable power of the wind to provide additional forward thrust and improve the energy efficiency of the vessel. This energy saving technology is increasingly being sought after by ship owners and operators as a cost-effective and immediate solution to reduce the carbon emissions and fuel consumption of their vessels, as well as helping meet international emission reduction targets.
Photo from signing ceremony, which took place at GSI offices on 14th May. Left to right: Nick Contopoulos – Chief Production & Partnerships Officer of Anemoi, Jesper Kristiansen – General Manager Technical of Hafnia, Huang Jun – Chief Engineer of GSI and Mr Shao Guang Chi – Station Manager of Guangzhou Station at DNV Maritime.