## 3 Hydrodynamic Characterization of Designed Hulls
In the data collection system architecture, six load cells located near the possibly highest loads were used to estimate the overall forces and moments transmitted by the sails and rig to the hull. The proposed GPS-aided inertial navigation test system computes the yacht attitude and boat dynamic. To acquire the angular rate, acceleration, and local magnetic field, gyroscopes, accelerometers, and magnetometers were arranged on the three primary axes, respectively. A GEMAC23554 analog inclination sensor installed beside the inertial navigation system was used to calculate the heel and trim angle. Furthermore, NMEA-GPS provided navigation data (wind speed and direction, boat speed, and depth). An ultrasonic 3D anemometer set on the yacht bow was used for the addition of wind measurement. Additionally, time of flight (TOF) technology was used to measure the 3D geometry of the sail flying shape, and MEMS sensors and pressure pads were used to estimate the sail pressure. All the obtained signals were collected and synchronized using data recording equipment. The majority of hydrodynamic tests are conducted in a towing tank environment, where the wave conditions are different from actual sea waves. In 2016, [PERSON] et al. [76] measured wave-induced motion and bending moment tested at a basin with realistic extreme seas on a cruise ship. In the experimental program, resistive wave sensors measured the wave-induced motion, and strain gauges calculated the vertical bending moment of the model. [PERSON] et al. [77] comprehensively proposed a comparative analysis between a small-scale laboratory seakeeping test and a large-scale seakeeping measurement test with realistic sea waves of a 72,000-ton class ship. In this research project, advanced onboard remote control and an experimental telemetry system were developed to realize seakeeping measurement at sea near the shore of the bay of Huludao, China. The project focused on measurement of wave data, navigational information, global motions and loads, accelerations, impact pressures, and visual recording (green water on deck, wave run-up, and slamming). The sensors used in the small-scale laboratory tests included wave probes, strain gauges, pressure sensors, accelerometers, rotary potentiometers, and data collectors. For the large-scale measurement systems, an anemometer, wave buoy, and tachometer measured the ocean environment. A fiber optic sensor was needed for the real-time hull stress monitoring and evaluation system. Then, sailing trace, position, speeds, and motions were calculated by a GPS/INS system. The radio control and telemetry system were developed to allow the conduction of large-scale model trials in sea conditions. As seen from the result, the proposed large-scale experimental test has tremendous significance for the future development of a large-scale seakeeping measurement technique. In 2019, [PERSON] et al. [78] proposed full-scale measurement onboard The Princess Royal research vessel to estimate the effect of biofouling growth on hydrodynamic performance. An automated sensor system was placed onboard the research vessel to acquire high-quality and quantitative hydrodynamic performance data. The results prove the effectiveness of the proposed method. In 2020, onboard measurement using several sensors installed on a bulk carrier ship was also investigated in depth by [PERSON] et al. [79]. This study proposed a data-driven approach to predict added resistance and shaft horsepower using big data from onboard sensor measurement and the NOAA database. For input features, various sensing methods and protocols were used to collect the input data. A GPS sensor was used to measure ship velocity, and a draft sensor was used to calculate the draft of the vessel. An RPM indicator and echo sounder were then used to determine the RPM and sea depth, respectively. To measure the tide, wave height, and wind vector, a Doppler sensor, accelerometer, and anemometer were installed onboard, respectively.