We aim to revolutionise load calculations on offshore structures using novel fluid mechanics to develop fast reduced-order engineering models. While the focus of this work will be examining the impact of extreme wave loading on the foundation systems supporting fixed offshore wind turbines, the ideas and tools generated will be more broadly applicable. We will develop a computationally fast method to be used by practicing engineers in industry to model long-term cyclic loading, leading to more efficient designs of offshore structures, reducing construction cost whilst preserving function and reliability.