Abstract: To reduce the mooring system cost of floating Oscillating Water Column (OWC) wave energy converter arrays while maintaining energy-capture performance and safety under extreme sea conditions, this study investigates the comprehensive performance of three-device shared-mooring arrays based on a floating cylindrical OWC device. First, a frequency-domain hydrodynamic model is established using AQWA. The PTO damping and the viscous damping are identified using Fluent, and the corrected damping parameters are introduced into an equivalent OWC model in OrcaFlex. Subsequently, physical model tests and numerical simulations are compared to verify the accuracy of the corrected equivalent model in describing the dynamic response and energy-capture performance of floating OWC devices. On this basis, an independently moored array and three shared-mooring arrays are constructed and compared in terms of motion response, mooring tension, energy-capture performance, and economy. The results show that, under operating sea conditions, the center-node shared-mooring configuration (Array-3C) achieves an average output power P_\textarr of 95.86 kW, which is 8.73% higher than that of the independently moored array (Array-3A, 88.16 kW). Meanwhile, the number of anchors is reduced from 9 to 6, and the total mooring line length is reduced from 909 m to 567 m. In addition, the annual energy production E_\textarr of Array-3C reaches 839 733 kWh, exceeding that of Array-3A (772 306 kWh). Considering overall performance in terms of motion stability, energy-capture efficiency, economy indicators, and safety under extreme sea conditions, Array-3C demonstrates superior integrated performance, indicating that rational design of shared-mooring configurations can enhance the engineering applicability of floating OWC arrays.