UK-based wind-assisted propulsion provider Anemoi Marine Technologies, Singapore-based tanker owner Hafnia, China-based shipbuilder Guangzhou Shipyard International (GSI), and Norwegian class society DNV have embarked on a collaboration to develop the integration design of rotor sails suitable for installation on 50,000 dwt medium-range (MR) tankers.
The JDP was signed in April 2025 and aims to develop vessel designs that incorporate Rotor Sails to improve the energy efficiency of MR tankers in the global fleet.
Under the agreement, Anemoi and Hafnia will conduct engineering studies to determine how Rotor Sails can be installed on MR tanker decks, including work on the electrical and control systems for these vessels.
The project will also evaluate the impact of Rotor Sails on the Energy Efficiency Design Index (EEDI) and the Energy Efficiency Existing Ship Index (EEXI) of both existing and new vessels.
GSI will contribute naval architecture and marine engineering services to produce technical documentation for the integration of the Rotor Sails.
DNV will perform an Approval in Principle (AiP) assessment to confirm that the design is technically viable and meets regulatory and class requirements.
Rotor Sails, also known as Flettner Rotors, are vertical cylinders that use wind to provide additional thrust and improve vessel energy efficiency.