Response-Based Forecasting of Vessel Motion: From Physics-Based to Data-Driven Methods

Abstract The conventional approach to assess the operability of floating facilities has typically been based on wave height and not wave-induced responses, which often form the basis of the operating envelope. During the last decade, this paradigm has been challenged through the development and provision of response-based forecasting. The availability of reliable measured motion data from vessels has enabled probabilistic rather than deterministic predictions, through the application of statistical methods. This has transformed decision-making in the field, increasing the efficiency and safety of offshore operations. This paper reviews the motivation and development of response-based forecasting, from the perspective of the authors, reflecting on the various case studies which have served as validation and led to refinement of the models. Focus is directed towards semisubmersibles operating in regions where long-period swell is prevalent. In these environments the hydrodynamic resonances of the vessel can be excited linearly, leading to significant motions which can exceed operating thresholds. We first examine the key inputs to response-based forecasting and the sources of uncertainty inherent to forecasting long-period swell and the treatment of viscous damping in vessel hydrodynamic heave response. The probabilistic methods which have been developed to account for these combined uncertainties are then demonstrated and evaluated. The findings of the study are highly generalizable and applicable to vessels used for the installation, production, and decommissioning, of both conventional hydrocarbons and offshore renewables.