HAMBURG, 26 APRIL 2018

The European Commission granted an innovative project intending to develop a biomimetic hull coating that reduces the frictional resistance of ships. The AIRCOAT project promotes a groundbreaking technology that has a high potential to revolutionise the ship coating sector and to be a game-changer for reducing energy consumption and emissions of Europe’s waterborne transport. A team of ten European scientists and industry experts led by the Fraunhofer Center for Maritime Technologies and Services will receive a total grant of 5.3 million Euro to develop and demonstrate the AIRCOAT prototype.

AIRCOAT (Air Induced friction Reducing ship COATing) develops a passive air lubrication technology that utilises the biomimetic Salvinia effect. This effect enables trapping air while submerged in water. The project technologically implements this effect on a self-adhesive foil system. Applying a ship with such an AIRCOAT foil will produce a thin permanent air layer, which reduces the overall frictional resistance significantly while acting as a physical barrier between water and hull surface. Therefore, besides substantially reducing main engine fuel oil consumption and hence exhaust gas emission, the air barrier further inhibits the attachment of fouling and the release of biocide substances (of underlying coatings) to the water and mitigates the radiation of ship noise.

The three-year project starts on May 1st 2018 and receives a total grant of 5.3 million Euro from the European Commission within the Horizon 2020 framework addressing the topic Innovations for energy efficiency and emission control in waterborne transport. Besides the Fraunhofer Center for Maritime Logistics and Services (CML), the interdisciplinary project consortium includes the German partners Karlsruhe Institute of Technology (KIT), the City University of Applied Sciences Bremen and the Ham-burg Ship Model Basin (HSVA). It further includes Avery Dennison Materials Belgium, PPG Coatings Europe BV from the Netherlands, Danaos Shipping from Cyprus, the AquaBioTech group from Malta, the Finnish Meteorological Institute and Revolve Water from Belgium.

The project is a prime example for a biomimetic application where technology is learning from nature. Nature has developed the Salvinia effect, which allows the Salvinia plant, a fern floating on the water, to breathe also under water by keeping a permanent layer of air. Now, technology makes use of this natural phenomenon. The Salvinia effect was described and elucidated within the BMBF ARES project of the Universities of Karlsruhe (KIT), Bonn and Rostock and a project at the KIT funded by the Baden-Württemberg Foundation. These projects already demonstrated the feasibility of air coating under water and its potential for technological applications. One of the pioneers of aircoating, the Nanotechnology expert Professor Thomas Schimmel from the KIT, who is the scientific coordinator of the AIRCOAT consortium, comments: “After understanding the Salvinia effect we challenged ourselves and came up with a methodology to produce an artificial surface that imitates the Salvinia effect in the laboratory. Every day, when entering my lab, I am again amazed to see that an early prototype, which we put under water more than 5 years ago, is still covered with a permanent air layer – keeping dry under water for more than 5 years!”. Professor Schimmel soon realised the large potential of this invention for the shipping industry. He joined forces with the Fraunhofer CML and they together conceptualised the AIRCOAT project to bring the prototype to the next level and to show its industrial viability. They therefore formed a consortium consisting of leading scientists from applied physics and nanotechnology, from experimental and numerical fluid dynamics, biomimetics, innovative ship technology and ship emission modelling together with industry experts from marine coating, ecotoxicology, self-adhesive foil and container ship owner.

The consortium develops small-scale prototypes to optimise the surface characteristics of this new technology supported by experimental and numerical methods. They further produces large-scale pilots to demonstrate the efficiency and industrial feasibility in operational environments (laboratory, re-search ships and container ship). Finally, they will perform a full-scale validation process to investigate and demonstrate the economic and environmental benefit. AIRCOAT Project Coordinator Johannes Oeffner from the Fraunhofer CML comments: “The potentials of AIRCOAT are enormous. Initial esti-mates show that the AIRCOAT technology can reduce at least 25% of main engine fuel oil consumption and hence 25% of exhaust gas emission.” Major advantages to existing technologies is that the ship hull is passively lubricated and that the refit technology would be immediately applicable to the whole fleet. Through combination with latest self-adhesive foil technology AIRCOAT can revolutionise the maritime coating sector and become a ground-breaking future energy efficiency and emission reduction technology.

Within AIRCOAT the Fraunhofer CML receives a funding of 1.14 million Euro. CML will coordinate the project and use its expertise in applied maritime science to bridge the gap between research and industry to ensure the holistic AIRCOAT approach. CML will contribute to optimising the AIRCOAT surface structure via experimental and numerical methods and analyse results allowing transfer to larger scales and application to real ships. Besides developing a method to quantify and monitor the air layer, CML will further be part of assessing the economic and environmental impact of AIRCOAT.