UK-based wind assisted propulsion system (WAPS) designer Anemoi Marine Technologies has completed the retrofit on another large vessel after installing five 35m units on the 400,000 dwt very large ore carrier (VLOC) ‘NSU Tubarao’.
The vessel, owned by bulk owner/operator NS United Kaiun Kaisha (NSU) and chartered by Vale International, is expected to reduce fuel consumption by 6% to 12% annually using WAPS. This marks the fourth VLOC installation of Anemoi rotor sails on vessels chartered by Vale. The completion of this installation means Anemoi has surpassed 1.6m dwt of vessel tonnage installed with its rotor sails.
The rotor sail installation on the five-year-old vessel, currently operating under a long-term charter to transport iron ore, was completed during scheduled drydocking in October 2025 at Zhoushan Xinya Shipyard in China. The rotor sails are deployed using a folding (tilting) mechanism for flexibility during cargo handling.
NSU has taken an industry-leading approach by combining rotor sails with advanced digital solutions that optimise power usage and vessel routing, enhancing fuel efficiency on NSU Tubarao and maximising the use of wind energy. Manta’s FuelOpt offers flexibility to the owner for power management of the main engine, including optimisation of fuel saved by the rotor sails, coupled with Napa’s voyage optimisation toolbox for voyage planning to maximise the benefits of favourable winds without compromising departure or arrival times.
During the scheduled special survey, NSU Tubarao was equipped with a new shaft generator designed to enhance efficiency. This upgrade not only improves the vessel’s own energy performance but also optimises fuel consumption when operating with rotor sails. Anemoi successfully integrated its rotor sail technology with the vessel’s shaft generator through advanced control system integration, ensuring seamless coordination between wind propulsion and onboard power supply. NSU’s forward-thinking approach to sustainable innovation means this installation is considered one of the most efficient WAPS retrofit projects to date.
Anemoi CEO Clare Urmston said: “The scale of this project shows the market’s growing confidence in wind power as a crucial enabler of lower emission shipping. Working with progressive partners like NSU, Vale and Class NK, we are able to advance rotor sail technology and show how optimising propulsion integration and navigation for wind assistance can deliver even greater benefits.” –
Toru Fujita, NSU Director and Managing Executive Officer, added: “At NSU we aim to support our stakeholders with the world’s most efficient ships. The rotor sails on NSU Tubarao, and the advanced systems that will help maximise its fuel-saving potential, are a perfect example of those efforts. We are pleased to have completed this successful installation, within the scheduled drydock, by strong collaboration of both Anemoi and the NSU team.”
NSU Tubarao is a 361m length overall, 65m beam VLOC delivered in September 2020. At 399,717 dwt, it is amongst the largest bulk carriers in the world. The five Rotor Sails onboard measure 35m tall and 5m in diameter, designed to maximise the Magnus effect that provides lift and thrust to significantly reduce engine propulsion demand in order to sail at a given speed.
Vale has set a target of a 15% reduction in scope 3 emissions by 2035, related to the value chain, of which shipping emissions are part, since the ships are not owned by the company.
Image: ‘NSU Tubarao’ VLOC (source: Anemoi Marine Technologies)
