Research Progress on Underwater Ship Propulsion in the Context of Green Transition—Energy Efficiency and Noise Reduction

Underwater propulsion technology is a core field within naval architecture and marine engineering, where decades of research and practice have yielded significant advancement. As the maritime industry moves toward sustainability in response to climate and ecological concerns, new priorities have emerged—particularly for energy efficiency, emission reduction, and noise suppression. These priorities are closely intertwined in the pursuit of sustainable propulsion. Considerable progress in these areas is documented in existing reviews, which offer in-depth discussions of either energy efficiency or noise issues. A systematic synthesis that integrates both aspects within the context of current industry trends and technological developments remains lacking. This paper reviews recent advances in underwater propulsion from the dual perspectives of efficiency enhancement and noise suppression. Furthermore, it examines the synergies and trade-offs between energy efficiency and noise reduction through a hydrodynamic lens, aiming to provide a comprehensive, multidimensional perspective for the future optimization and design of underwater propulsors.