bound4blue, ITER conduct wind tunnel testing to enhance eSAIL

Spanish cleantech engineering company bound4blue has collaborated with the Institute of Technology and Renewable Energies (ITER), a Tenerife-based energy institute, for aerodynamic tests at the ITER wind tunnel facilities, focusing on optimizing suction sail systems for large vessels.


The tests were carried out throughout October 2023.

As informed, the testing campaign confirmed system improvements, showcasing bound4blue’s commitment to advancing clean propulsion technology and cost-effective propulsion solutions in the maritime industry.

The ITER wind tunnel provided ‘an ideal environment’ for fine-tuning and enhancing the performance of these propulsion systems, according to bound4blue.

bound4blue has been at the forefront of research and development in propulsion systems using suction sails, combining the advantages of rigid sails and flettner rotors while mitigating their drawbacks. The company’s modernized suction sail, named eSAIL, converts wind into direct propulsion for vessels, allowing shipowners and operators to reduce their environmental footprint and cut fuel costs.

In 2021, ITER collaborated with bound4blue in preliminary tests, studying the suction sail profile, pressures, and speeds to determine optimal configurations. As the research evolved, new needs emerged, leading to a detailed evaluation of the suction area to optimize its performance.

For this latest campaign, ITER played a pivotal role in constructing the test model and integrating various suction area configurations. Precision instrumentation, including high-precision pressure measurements with scanners and a fan simulating suction sail operating conditions, was employed to gather crucial data.

The results of this testing campaign allow bound4blue to confirm improvements in their systems and validate existing theoretical calculations.

“In our quest to constantly improve, we wanted to focus on a single but crucial detail in the complex aerodynamics of a suction sail, the suction area. The facilities at ITER are perfect for this, and we could not have done it without the incredible help and dedication from the ITER team. The data gathered allows us to validate our internal tools with the ultimate goal of improving the performance of the eSAIL,” Alberto Llopis, Lead Aerodynamics Engineer of bound4blue, said.

In September this year, eSAIL was selected by French maritime firm Louis Dreyfus Armateurs (LDA) for installation on its RoRo vessel Ville de Bordeaux.

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What is more, Norwegian shipping company Odfjell decided to install the eSAIL system on a chemical tanker, making it the first tanker vessel in the world to harness this groundbreaking technology.

The technology has also been implemented on Amasus’ general cargo ship EEMS Traveller, Marubeni’s Panamax bulk carrier Crimson Kingdom and La Naumon, the first theater vessel in the world.