Wind assisted propulsion system (WAPS) develper bound4blue has achieved another milestone, with an ABS review of its proprietary force matrix methodology for calculating Pwind values adding to the classification society assessments of bound4blue’s methodology.
The company says this gives shipowners added confidence when quantifying regulatory and financial benefits of its eSail suction sails, helping accelerate adoption and streamline compliance.
bound4blue’s approach aims to deliver both confidence and speed. The innovative methodology combines advanced CFD modelling with wind tunnel validated tools to generate vessel-specific aerodynamic force matrices. As such it avoids the need for expensive and time-consuming full-scale testing, while still accounting for both sail-to-sail and ship-to-sail aerodynamic interactions. This ensures each installation is assessed according to its unique configuration and operating characteristics.
Achieving reliable calculations is an increasingly important regulatory step for shipowners looking to embrace clean, readily available and proven wind power. Verified Pwind values can be used within EEDI and EEXI calculations, while helping to determine FuelEU Maritime’s Wind Reward Factor. While such methodologies do not indicate factors such as fuel savings or hydrodynamic performance, they do shed light on reduced compliance costs, strengthening the overall business case for wind propulsion.
José Miguel Bermúdez, CEO and co-founder, bound4blue, said: “In a transitioning, and increasingly complex, industry, third party reviews deliver both certainty and transparency for shipowners considering suction sail installations. That is a vital factor in accelerating the adoption curve for advanced wind propulsion technology. Independent review from leading class societies such as ABS gives stakeholders confidence that the aerodynamic methodology behind our Pwind calculations is robust, credible, and suitable for regulatory use. This creates a clear pathway to compliance, making it easier for shipowners to capture not only the environmental benefits of wind propulsion, but also the significant financial advantages available through today’s regulatory frameworks.”
The review indicates that bound4blue’s methodology can be applied with confidence across future projects. While each WAPS force matrix remains specific to an individual vessel and installation, the underlying process has undergone expert third-party assessment, unlocking reduced project development and approval timelines for future eSail installations.
Alberto Llopis, Head of Aerodynamics, bound4blue, added: “The focus of this review is the generation of accurate aerodynamic polars and force matrices that represent how eSail systems perform under different wind conditions. Our methodology combines sophisticated CFD calculations and in-house tool development with extensive wind tunnel validation to provide insights into complex aerodynamic interactions. We’re delighted to have worked with ABS, as we continue in our quest to build confidence and credibility for wind power amongst shipowners, financiers, charterers and other key stakeholders.”
Michael Kei, ABS VP Technology, said: “ABS is committed to supporting the safe adoption of innovative technologies that help the industry comply with evolving regulations. We are pleased to work with bound4blue on their technology, helping provide a clear and consistent framework for evaluation of wind-assisted propulsion systems and supporting informed decision-making across the industry.”
The methodology used by bound4blue to determine force matrix from the combination of RANS-based CFD simulations, wind tunnel model tests, and potential-based interference analysis for multiple installation of eSail was reviewed in accordance with applicable IMO regulations and ITTC guidelines. bound4blue has won a number of high-profile contracts and installations for its autonomous, suction sail technology.
eSails are claimed to generate forward thrust up to seven times greater than conventional rigid sails of the same size. By harnessing wind as a clean energy source, they ease engine loads, reduce fuel consumption and decrease GHG emissions, supporting both regulatory compliance and financial performance. The mechanically simple, non-ATEX units are suitable for a range of vessel types, including tankers, bulkers, ro-ros, cruise vessels, ferries, gas carriers, and general cargo vessels. The company has deployed eSail systems on 11 ships, with seven more in its order book, representing more than 50 eSails.
Image: Top down CFD result of vessel with 4 eSails showing flow field variations due to sail-to-sail and ship-to-sail interference (source: bound4blue)
