The sail demonstrates China’s ability to compete in wind‑assisted ship propulsion, potentially lowering emissions and diversifying energy sources for global shipping.
Rotor sails, which harness the Magnus effect to turn wind into forward thrust, have become a focal point of the maritime industry's low‑carbon transition. Unlike traditional sails, these rotating cylinders generate consistent propulsive force even in variable wind conditions, allowing vessels to shave up to 10% off fuel consumption. The technology complements emerging hybrid and electric propulsion systems, offering a modular retrofit option for existing fleets while aligning with IMO’s 2050 decarbonisation targets.
China’s debut of a 5‑metre‑diameter, 35‑metre‑tall rotor sail marks a strategic leap in domestic wind‑assisted propulsion capabilities. By integrating ultra‑large composite moulding, lightweight structural design, and end‑to‑end assembly, Sunrui Composites has closed a critical innovation gap that previously forced Chinese shipowners to import foreign systems. This home‑grown solution not only reduces supply‑chain reliance but also positions CSSC’s subsidiaries as credible competitors alongside Finland’s Norsepower, Singapore’s Dealfeng, and the UK’s Anemoi Marine, intensifying global market dynamics.
Looking ahead, widespread adoption will hinge on rigorous sea‑trial validation, regulatory acceptance, and cost‑competitiveness. The Dalian land‑based tests aim to prove long‑term reliability and environmental adaptability, paving the way for commercial retrofits on bulk carriers and container ships. If performance data confirms projected fuel savings, rotor sails could become a standard auxiliary propulsion option, accelerating the shipping sector’s path toward net‑zero emissions while opening new revenue streams for composite manufacturers and marine engineering firms.
China has a new competitor in the rotor sails industry. The Luoyang Ship Material Research Institute – a subsidiary of the state-owned China State Shipbuilding Corporation (CSSC) – supervised the collaboration between its two subsidiaries Sunrui Environment and Sunrui Composites to develop a large-scale rotor sail, at its Dalian base, Liaoning province. “The launch of this rotor sail fully demonstrates the technological strength and industrial advantages of Sunrui Composites in the field of composite materials equipment for new energy ships. It also marks a leap forward in China’s large ship sail technology, filling a gap in domestic independent research and development and manufacturing of this type of equipment,” says Sunrui Environment.
The new rotor sail features an outer tube diameter of 5 metres and a height of 35 metres. It boasts comprehensive energy efficiency thanks to its lightweight design and refined manufacturing process. Its quality uniformity and dimensional consistency meet international standards. Based on the Magnus effect, this equipment converts wind energy into propulsion for ships through a rotating wind tunnel, making it a powerful tool for carbon reduction in the shipping industry.
Sunrui Composites has fully leveraged its expertise in composite materials and the manufacture of large structural components, achieving a breakthrough in a range of key technologies, including ultra-large cylinder moulding and lightweight structure design, and developing an integrated capability from basic component development to complete machine assembly and testing. The collaboration between Sunrui Environment and Sunrui Composites represents a practical achievement of complementary strengths and collaborative innovation among the Luoyang Ship Material Research Institute’s industrial units. Since the project’s inception in 2025, the two teams have worked together, integrating their respective technological knowledge in wind power and marine environmental protection equipment.
At the Dalian test site, six leaders from both companies took to the stage to cut the ribbon for the rotor sail’s completion, jointly witnessing the rollout of “the world’s largest rotary sail”, according to Sunrui Environment. Subsequently, Yu Jiangshui, general manager of Sunrui Environment, and Shi Junhu, general manager of Sunrui Composites, activated the testing equipment, officially commencing the next phase of land-based testing for the rotary sail. This comprehensive verification of the product’s long-term reliability, operational stability, and environmental adaptability lays the foundation for its future engineering applications.
In the era of low-carbon transformation in the global shipping industry, rotor sail technology has become a key development area of focus with broad market prospects. With this new large-scale rotor sail, Sunrui Composites enters an already busy arena. In December 2024, Norsepower, the major Finnish specialist of wind-assisted propulsion for the maritime industry, announced the opening of its first dedicated rotor sail factory in Dafeng, Jiangsu province. In May 2025, Singapore-based shipowner Hungze has signed a cooperation agreement with Dealfeng, a Chinese company specialised in the design and installation of wind-assisted propulsion systems. And in September 2025, Anemoi Marine Technologies, a British provider of wind propulsion solutions, opened a new rotor sail production facility in Jingjiang City, Jiangsu Province, in collaboration with local specialist Zhongfu Lianzhong Composites.

Six leaders from both companies took to the stage to cut the ribbon for the rotor sail’s completion, jointly witnessing the rollout of “the world’s largest rotary sail” (source: Sunrui Environnment)
Cover photo: The launch ceremony of the large-scale rotor sail was held at the test site in Dalian, Liaoning province (source: Sunrui Environnment)
Comments
Want to join the conversation?
Loading comments...