Investigation of mooring anchor installation deviations and GA-based correction strategies for a 15 MW FOWT in shallow water

Anchor installation deviations are often unavoidable during installation. For floating offshore wind turbines (FOWTs) in shallow water, such deviations threaten mooring safety due to the pronounced nonlinearity of catenary mooring systems in limited water depths. This study analyzes the effects of anchor installation deviations for a 15 MW semi-submersible FOWT at 50 m water depth, and proposes a genetic algorithm (GA)-based correction method to mitigate these effects. Fully coupled time-domain simulations are conducted under operational and extreme conditions, covering single-anchor and coupled multi-anchor deviation scenarios. A validated quasi-static mooring analysis code evaluates fitness within the GA framework. Radial anchor deviations significantly affect mooring line tension, while tangential deviations have negligible impact. Non-uniform coupled deviations induce severe stiffness asymmetry and load redistribution, with the most critical case increasing the maximum tension by over 40% and reducing the safety factor from 1.87 to 1.33, below the required 1.67 threshold. The GA-based correction restores system performance, reducing the restoring force deviation by 90.7% and recovering the safety factor to 1.68. This work provides an analysis and correction framework linking deviation impact analysis to mooring safety enhancement for shallow-water FOWTs.