The offshore photovoltaic (PV) systems confront numerous challenges in marine settings, such as wave motion, salt spray corrosion and partial shading. This research develops a multi-physics framework that combines electrical modeling, hydrodynamic analysis and fault mechanisms. A single-diode model dynamically calibrated simulates PV behavior under environmental changes. The JONSWAP wave spectrum is used to measure platform tilt dynamics, thus determining critical overturning thresholds when tilt angles surpass 90°. Salt spray-induced resistance degradation and probabilistic fault models show long-term performance degradation due to corrosion. Results indicate that wind speed increases power dispersion (15–140 W at 20 m/s, with an IQR-speed correlation R2 of 0.82). Moreover, wave induced tilt fluctuations combined with dynamic shading result in multi-peak IV/PV curves, reducing maximum power point tracking efficiency. Dynamic fault injection identifies wave-shading coupling features, facilitating the creation of a multi-physics fault database. The combination of JONSWAP-based tilt modeling and adaptive electrical corrections enhances anti-overturning design criteria and intelligent fault diagnosis strategies. This provides crucial insights for improving offshore PV system reliability in complex marine environments.