Real-time flying shape detection of yacht sails based on strain measurements

The flying shape detection of boat sails whilst racing may offer valuable insight into the sail design and performance. This paper describes a monitoring system based on fiber optic strain gauge sensors used to reconstruct in real time the form of a sail. For this purpose, a developed and implemented algorithm converts strain measurements into curvatures and integrates those in order to identify the sail deformed shape and the most significant parameters used in its characterization. Experimental studies are carried out in laboratory to validate this concept using a glass-fiber-reinforced polymer (GFRP) pultruded profile and fiber Bragg grating (FBG) sensors fixed and deformed on a calibrated board reproducing common configurations of the sail shape. It is shown that 5 instrumented sections along the beam using 10 FBG sensors are required to evaluate the profile of deformed sails, leading to maximum errors in the estimations of the sail parameters lower than 5%.