THE CRITICAL ROLE OF ACCURATE WIND MEASUREMENT FOR WIND ASSISTED SHIP PROPULSION Various types of mechanical sails for WASP - Rotor Sails (left), Wing Sails (right) Mechanical sails are currently used in wind prime applications, and wind for assisted propulsion both are devices which have been designed in such ways - and developed with such mechanical means - to automatically adjust their properties so that they maximise the delivered Thrust per square meter of Sail surface against the incoming winds, by arti昀椀cially elevating their aerodynamic properties, while working with the least human intervention, being semi or fully automated. In particular, the enhancement of aerodynamics is taking place through regulating the below parameters as applicable per di昀昀erent mechanical sail technology and type: • Rotor Sails: spinning RPM; • Suction Wing Sails: suction fan RPM, 昀氀ap positioning and Angel of Attack (AoA) orientation against the wind; • Wing Sails: 昀氀ap positioning and AoA orientation; and • Airborne Towing Kite: Height of 昀氀ight adjustment from the ship’s deck and positioning against the ship’s forward course. Mechanical Sails cannot automatically and e昀昀ectively adjust any of their functional parameters to deliver performance, without a means to accurately detect and interpret the current incoming apparent wind direction and wind speed on a moving ship. Therefore, a wind sensing system is probably the most important component of any given mechanical sail technology, no matter how advanced mechanics, software intelligence or other novel approach is incorporated to maximise performance. Without proper wind sensing, the performance is undermined and ultimately compromised. 7