Abstract: In the context of the widespread promotion of green shipping concepts and the increasingly strict regulations governing international carbon emissions, Wind-Assisted Ship Propulsion (WASP) technology has re-emerged as a significant research hotspot within the maritime field, serving as a core pathway for ship energy saving and emission reduction. Taking Flettner rotors and Rigid sails as the core objects of investigation, this study aims to systematically clarify the wind energy capture mechanisms, thrust conversion laws, ship-sail coupling characteristics, and the logic of real-ship adaptation for these two types of sails. 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 concept verification to large-scale engineering application.Through a systematic classification and comprehensive analysis of current research results, it is observed that scholars predominantly adopt research methodologies that combine "numerical simulation, wind tunnel testing, and full-scale ship testing." Focusing on aspects such as wind energy capture, thrust conversion, ship-sail coupling, and engineering adaptation, this paper comprehensively analyzes 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, relying on the Magnus effect, can achieve a peak lift coefficient of up to 17.97 under crosswind conditions. Meanwhile, Rigid sails, through multi-element airfoil optimization, demonstrate lift-to-drag ratios that are significantly superior to traditional sail types within the optimal angle of attack range. Under specific operating conditions, both types of sails are capable of achieving energy-saving rates ranging from 5% to 30%. Specifically, Flettner rotors are particularly suitable for ship types with rigorous safety requirements, such as oil tankers and LNG carriers, whereas Rigid sails exhibit higher energy-saving potential in bulk carriers and VLCCs. However, the performance of both systems is significantly influenced by environmental and operational parameters, with clear boundaries for operational adaptation. Furthermore, multi-sail arrays exhibit aerodynamic interference effects, necessitating layout optimization to mitigate adverse impacts.In summary, current ship WASP technology remains in a transitional stage toward engineering implementation. Future research efforts need to prioritize breaking through 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 improving system reliability, promoting multidisciplinary design optimization, and accumulating long-term full-scale operational data, the ultimate goal is to promote the large-scale application of this technology in the global shipping system, providing essential technical support for the shipping industry to achieve the "2050 Net Zero Emissions" target.