The effective power of a design representative ship type is a pivotal parameter for determining the hydraulic parameters of rapids abating.Addressing the issues in current engineering design where the high dispersion of operational power data and dimensional discrepancies between existing vessels and typical ship-types lead to a lack of unified criteria for main engine power determination,a study on the determination method of effective power based on regulatory constraints is conducted.By incorporating the mandatory minimum design speed regulations for different navigation zones and utilizing an improved power regression prediction model,a standardized calculation workflow transitioning from standard principal dimensions to statutory minimum speed and subsequently to effective power is established.Taking the 1 000-ton-class typical ship-type in the reservoir head of the Wudongde on the Jinsha River as a verification case,the results indicate that the effective power required to meet the minimum speed requirement of the J1 navigation zone is approximately 415 kW,corresponding to a rated main engine power range of 1,012-1,092 kW.This aligns closely with the actual configurations of high-power vessels recently commissioned in this reach.The proposed methodology effectively mitigates the uncertainties associated with traditional empirical analysis methods in determining ship dynamic parameters and provides a technical foundation for the scientific determination of hydraulic parameter navigation in rapids and regulation scales