A packed audience heard two contrasting but complementary perspectives on the rapid rise of wind-assisted propulsion.
On the second day of this year’s Propulsion and Future Fuels conference in Hamburg, a packed audience heard two contrasting but complementary perspectives on the rapid rise of wind-assisted propulsion. The panel, moderated by Gavin Allwright, secretary of IWSA, featured a number of speakers including Lauren Eatwell, head of WindWings at BAR Technologies, and Dr Uwe Hollenbach, senior principal engineer at DNV Maritime Advisory, offering both a technology developer’s insight and a class society’s view on verification, modelling and risk.
Eatwell began by tracing BAR Technologies’ origins back to the British America’s Cup team. The highly advanced simulation environment developed for racing yachts – where towing tanks and wind tunnels are prohibited – became the foundation for the company’s commercial maritime activities. By 2017 it was clear that the same tools that refine elite sailing performance could be translated into merchant shipping, and BAR Technologies was established to do exactly that. The company now works across wind propulsion, hull and appendage optimisation, underwater foiling technology and aerodynamic superstructures. For the Hamburg audience, Eatwell focused on the firm’s WindWings systems.
The technology is already operating at full scale. The Pyxis Ocean, launched in 2023 in partnership with Cargill and Mitsubishi-owned Mitsui O.S.K. Lines, carries two 37.5-metre three-element wings. The Newcastlemax Berge Olympus followed with four wings, making it, by thrust, the most powerful sailing vessel in the world. As BAR shifts into industrial production with new manufacturing partner China Merchants, fleet rollout is accelerating, with more than 20 additional wings scheduled for delivery next year and smaller variants being introduced for vessels with tighter space or crane constraints.
The three-element wing configuration emerged from extensive simulation, not assumption. BAR’s team combined velocity prediction programmes, CFD, drivetrain modelling and ten years of real-world weather data. Thousands of simulated passages allowed them to determine the apparent wind conditions experienced across typical global routes and to design a wing capable of delivering the highest average fuel benefit. According to Eatwell, a three-element profile provides both the most efficient lift and the greatest controllability across the headwind-dominated apparent wind angles seen at commercial ship speeds. Adding further elements yields diminishing returns.
BAR now has sufficient operational data to benchmark simulated predictions against reality. Eatwell detailed the rigorous on/off testing developed with DNV to isolate the effect of the sails on shaft power and fuel consumption. By selecting time periods with consistent wind and wave conditions and comparing stabilised power readings with the wings engaged and disengaged, both BAR and DNV have been able to verify results at a high level of confidence. In moderate apparent winds, fuel savings align closely with predictions; the first voyages of recent installations have reported up to 12 tonnes of fuel saved per day, reinforcing trust in the statistical performance models that underpin BAR’s customer guarantees.
Eatwell closed by emphasising the importance of standardisation. With design approval already secured from Bureau Veritas, Lloyd’s Register and DNV, and type approval progressing, the company is working across the industry to harmonise simulation methods, testing protocols and performance reporting to ensure transparency and comparability as wind propulsion scales.
Dr Uwe Hollenbach offered the class society and modeller’s view of the same emerging landscape. Although speaking in his DNV capacity, he drew on the operational challenges faced by wind-assist providers and shipowners. He described the current market as analogous to a car showroom: all buyers want fuel savings, but each measures value differently. Some are primarily motivated by regulatory compliance and index ratings, while others are driven by operational fuel expenditure, trading patterns or vessel flexibility. A single “sticker value” cannot capture every operational profile, and therefore accuracy, fairness and consistency in ratings and verification are essential if regulations are to achieve their intended effect.
Hollenbach highlighted two distinct customer archetypes emerging in the market. Some owners want quick, practical add-ons to save fuel without major design changes; others are prepared to commit to radically different vessel concepts with large wind installations and smaller engines, targeting 50–60% wind contribution without sacrificing schedule reliability. Such designs push both aerodynamic and hydrodynamic modelling into new territory. Interaction effects between sails, superstructures and hulls become far more complex, requiring coordinated work between technology developers, designers, shipyards and class societies.
For emerging wind-assist manufacturers, Hollenbach noted, a central challenge is trust. High-performance prototypes may show promise in simulations and wind tunnel testing, but no operator has yet accumulated years of data on some of the newest concepts. This is where regulatory frameworks, structured testing programmes and third-party verification become vital. Through joint industry projects with partners such as MARIN and national initiatives in France, DNV and other organisations are building shared modelling approaches, aerodynamic and hydrodynamic libraries, and validation methods that will support a more mature and comparable marketplace.
He also pointed out a commercial reality that often gets lost in the complexity: the cost of fuel that is not burned is zero, and the wind remains free. Upfront capital expenditure can deter owners, but once installed, a portion of a vessel’s propulsive energy becomes permanently immune to fuel price volatility and carbon costs.
Ideas shared by the pair included collaboration being essential for wind propulsion to scale meaningfully. Whether through BAR Technologies’ industrial partnerships or the research alliances described by Hollenbach, every successful project depends on integrating aerodynamic expertise, hull design, ship operations and regulatory compliance.
