Multi-step optimization with operational scenarios for hull form and propulsor design for pod-driven cruise ships

With the increasing demand for reducing CO2 emissions by the International Maritime Organization (IMO), controlling a ship's energy consumption at the design stage is crucial for proposing a 'greener' design. Some efforts have been made to consider the Energy Efficiency Design Index (EEDI) and the Energy Efficiency Operational Index (EEOI); however, the latter remains highly complex and contentious. In this study, a multistep optimization analysis method was developed to integrate EEDI and EEOI evaluations during the design stage to meet low emission requirements. Additionally, an Efficient Operational Scenario Analysis Method (EOSAM) was established to consider operational energy efficiency. This method was applied to optimize the hull and propulsor design of a pod-driven cruise ship. By accounting for operating conditions in both calm water and wave scenarios, and utilizing high-fidelity computational fluid dynamics simulations and model test validation, the delivered power was reduced by up to 7.1 % compared to the original design, and the EEOI decreased by an average of 16.7 %.