THE CRITICAL ROLE OF ACCURATE WIND MEASUREMENT FOR WIND ASSISTED SHIP PROPULSION INTRODUCTION The shipping industry has an environmental and commercial imperative to decarbonise. The regulatory framework developed by the IMO (International Maritime Ogranisation), the European Union and other Shipping Nations projects a gradual phase-out of GHG emissions from ships, with the IMO aiming at 70% reductions by 2050, while ongoing negotiations may bring a zero-emissions requirement by the same year. It is not only about imposing carbon levies to penalise polluter ship owners and operators: it is also about introducing carbon footprint per fuel energy spent (FuelEU Maritime[1]) and fuel lifecycle GHG intensity (IMO[2]), which will necessitate a large improvement of ship performance both by means of energy e昀케ciency and of low or zero carbon fuel/energy usage. The exploitation of Winds in the oceans for propulsion is an old concept, but still available as an abundant, inexhaustible source of energy with no price 昀氀uctuations. The traditional Sails that were once used for ship sailing and trading were comprised of large soft material surfaces which could be deployed when the wind was blowing, tightened, and twisted through ropes to develop a stable and e昀昀ective aerodynamic surface, with the mast turned to orientate appropriately with the incoming winds. This requires continuous human e昀昀ort and elaborative training for the decision making on the Sail adjustments and the assumptions around about the wind conditions surrounding the vessel. Modern ships though, having large displacements, are carrying relatively heavy cargo’s compared to the historical wind sailing ships, and require higher trading speeds, thus increased propulsion power, a combination of performance features which turned the shipping community to rather opt for more powerful internal combustion engines and mechanical propelling systems. Since the early years of the Millennium, a new breed of sailing systems for shipping were devised and developed for adoption and, with the primary aim to reduce high fuel costs for such high-power demand by improving energy e昀케ciency: the Mechanical Sails; Airborne Towing Kite during [3]; and the Flettner Rotor Sail[4]. MODERN SAIL OPTIONS Rotor Rigid wings Soft wings Soft Ventilated foil 70% BY 2050 6