Abstract: In the context of the growing emphasis on green shipping and increasingly stringent regulations governing international carbon emissions, wind-assisted ship propulsion (WASP) technology has re-emerged as a significant area of research within the maritime industry, serving as a critical pathway for reducing energy consumption and carbon emissions in shipping. Taking Flettner rotors and rigid sails as the core objects of investigation, this study aims to systematically explore the mechanisms of wind energy capture, the principles of thrust conversion, ship-sail coupling characteristics, and the rationale behind the adaptation of these sails to real-world ships. The primary objective is to comprehensively evaluate their application potential and engineering feasibility across different ship types, thereby providing robust theoretical support and practical references for facilitating the transition of this technology from conceptual validation to large-scale engineering application. Through a systematic classification and comprehensive analysis of current research results, it is evident that scholars primarily adopt research methodologies that integrate "numerical simulation, wind tunnel testing, and full-scale ship trials." Focusing on aspects such as wind energy capture, thrust conversion, ship-sail coupling, and engineering adaptation, this paper provides a comprehensive analysis of the aerodynamic performance, energy-saving benefits, and operational constraints of the two types of sails under varying sea conditions, apparent wind angles, and ship configurations. The overall research findings indicate that Flettner rotors, which rely on the Magnus effect, can achieve a peak lift coefficient of up to 17.97 under crosswind conditions. In contrast, rigid sails, optimized through multi-element airfoil design, exhibit significantly higher lift-to-drag ratios than traditional sail types within the optimal angle of attack range. Under specific operating conditions, both sail types can achieve energy-saving rates ranging from 5% to 30%. Specifically, Flettner rotors are particularly well-suited for ship types with stringent safety requirements, such as oil tankers and LNG carriers, whereas rigid sails offer greater energy-saving potential in bulk carriers and VLCCs. However, the performance of both systems is heavily influenced by environmental and operational factors, with clear limits on their operational adaptability. Furthermore, multi-sail arrays exhibit aerodynamic interference effects, necessitating layout optimization to minimize negative impacts. In summary, current WASP technology remains in a transitional stage toward engineering implementation. Future research efforts should focus on overcoming four critical challenges: the optimization of ship motion and sail coupling, stability control under strong wind conditions, the quantitative prediction of multi-sail interference, and the integration of full lifecycle economics. By enhancing system reliability, promoting multidisciplinary design optimization, and gathering long-term full-scale operational data, the ultimate goal is to facilitate the large-scale adoption of this technology within the global shipping industry, providing essential technical support for achieving the "2050 Net Zero Emissions" target.