In spite of the considerable development in the field of marine protective coatings, there is still significant room for improvement. Very long lasting (20+ yrs) coating systems that offer reliable protection against corrosion/biofouling or corrosion/cavitation, and which also avoid the need for supplementary cathodic protection are not available. The need for such coatings is acute in the case of static offshore structures, where dry docking is not an option. The growth part of this market relates to new build structures ranging from offshore wind turbine foundations to ocean energy devices.The SMEs proposing the ACORN project are interested in an alternative, highly differentiated and patentable technical solution to the above problem. The project will develop a new, patentable and long-lasting solution to the problem of marine biofouling, offering specific advantages for static offshore structures such as wind turbine towers and ocean energy generators. The new technology could also be extended to shipping in the longer term.ACORN will take advantage of the proven long-term corrosion resistance of thermally sprayed aluminium (TSA) to provide a matrix coating with a proven life of 20+ years in the sea. Into this porous TSA matrix, the ACORN research team proposes to introduce islands of environmentally friendly antifouling substances which can then be gradually exposed at the active surface of the coating as the TSA corrodes away at 10µm per year.This will result in an entirely new, non-paint, approach to the long term protection of offshore structures. In addition to this, the project will also develop and prove a corrosion and cavitation-resistant coating with a 10+ year design life, suitable for tidal energy generators.