The increasing demand for renewable energy has amplified the need for subsea structures, which needs safe installation through splash zone crossings. To ensure safety, dynamic analyses of splash zone effects are essential. Although there are various modeling approaches, full-scale validation is still lacking. In addition, a structured framework for selecting the most reliable modeling approach under different conditions has not yet been established.

This study evaluated three approaches, a stationary frequency-domain model, a stationary time-domain model, and a transient time-domain model, by comparing simulated roll and pitch simulated responses with full-scale measurements from three different subsea template installations. Simulations were performed using both wave rider buoy (WRB)-based and forecast-based wave spectra to assess the influence of environmental data sources.

The stationary models consistently produced conservative results, overestimating measured responses. However, the stationary frequency- and time-domain models showed strong mutual agreement on both roll and pitch during the three installations. Forecast-based simulations systematically underestimated responses compared to WRB-based simulations. The transient model, when combined with WRB-based wave spectra, reproduced measured responses more closely in terms of spectral energy and significant amplitudes. The transient model, when combined with forecast-based wave spectra occasionally underestimated both spectral energy and significant amplitudes.

The stationary models overpredicted responses, because they assumed steady-state resonance at a fixed draft. Since the stationary frequency-domain and time-domain models showed strong consistency, both can be considered validated against each other. The transient model, as an extension of the stationary time-domain model, captured the dynamic responses more realistically and showed good alignment with measurements, although high-order effects, such as slamming and quadratic viscous damping, were not included. Overall, the stationary models are conservative for transient load cases, while the transient model provides a more accurate prediction of dynamic splash zone responses. Further research is recommended on high-order effects, which may become governing near resonance and in low-energy sea states.