Objectives In the context of global carbon reduction, in order to meet the environmental require-ments of the design and construction of polar ships, this paper studies the impact of brash ice on the optimal design of polar expedition cruise ships when navigating across oceans and designs the most optimal energy-saving hull lines.

Methods In view of the transoceanic characteristics of polar expedition cruise ships, the navigation region-based weighting method is used to quantify the evaluation and analyze the impact of brash ice on resistance and propulsion efficiency. An analysis is carried out of the performance of the propeller in broken ice channel through the coupling calculation of the computational fluid dynamics-discrete element method (CFD-DEM), an optimization model with the goal of combined self-propulsion power is established, and optimization calculations are performed for the parametric model of the whole ship at the designed speed.

Results The calculation results show that the optimized ship hull meets the requirements of displacement and effectively reduces navigation power in open water and broken ice channel with a combined self-propulsion power reduction of 9.71%.

Conclusions The results of this study verify the feasibility and rationality of optimization based on the weighting method, and can provide references for the optimization design of hull form and thrusters of polar expedition cruise ships.