Optimization of a single-point buoy mooring system for a novel hexagon-shaped floating unit via surrogate model-based particle swarm optimization method

Over the decades, various mooring systems have been developed and implemented to address the diverse application requirements of offshore floating platforms. Achieving cost-effectiveness while ensuring operational safety remains a critical challenge in mooring system design. Aimed at a novel hexagon-shaped floating unit (HSFU), a cost-effective single-point buoy mooring (SPBM) system, consisting of two mooring lines and a buoy, is proposed here by utilizing the weathervane effect. To evaluate the effectiveness of the proposed mooring system, an accurate time-domain analysis was performed via SESAM software, considering the time-dependent feature of the buoyancy provided by the buoy. To find an optimal mooring configuration, an optimization framework integrated with the response surface model (RSM) and Particle Swarm Optimization (PSO) algorithm was established, aiming to minimize the total cost of the SPBM while considering safety and serviceability constraints. The optimized SPBM system exhibited improved cost-effectiveness and enhanced performance compared to the initial design, with the total mooring cost, surge range, and mooring line tension reduced by 7.5%, 17.5%, and 8.9%, respectively. Additionally, when compared with an optimized catenary single-point mooring (CSPM) system, the optimized SPBM provided comparable motion responses while reducing the total cost by 59.2%. These findings indicate that the proposed SPBM system offers a technically feasible and cost-effective mooring solution for offshore floating structures.