The aim of this project is to investigate the performance of a novel wind-capturing device that would allow the installation of wind turbines in deep sea, leveraging floating spar-like platforms to prop the towers. The project envisages the simulation, with high-fidelity computational tools, of a floating offshore wind turbine concept that comprises the use of a vertical-axis double-rotor structure. Offshore wind has not yet reached economic profitability due to the high costs of installation and maintenance, and further research is required to lower the Levelised Cost of Energy (LCoE) of wind energy; previous investigations suggested that scaling up the wind turbine could reduce the LCoE by up to 23%. The Counter-Rotating vertical-Axis Floating Turbine (CRAFT) would permit the installation of power generators of up to 40MW, reaching a total tower height of 400 m, with an additional boost on the power production per area of the wind farm. CRAFT device, conceived by World Wide Wind AS (Norway), is an innovative design for the exploitation of offshore wind resources, and it allows widening and optimizing the usable sea area by increasing the installing depth, possibly to hundreds of meters. The research group has experience in the use of Computational Fluid Dynamics (CFD) methods applied to wave energy converters, including a high level of complexity within their simulation by embedding power take-off systems and anchoring systems. CRAFT will be simulated in ordinary and extreme sea conditions (combination of wind and sea states) to provide a first proof of concept, thus building up a useful set of information towards the realizations of the first physical tests, which would be then possibly followed by the first pilot plant.