In response to bottlenecks such as excessively long discharge distances,low efficiency in clay transport,and insufficient system stability in the large-scale and long-distance development of port and waterway dredging projects,the research on the optimal layout design and construction control technology of relay pump vessels to enhance the feasibility and economy of clay transport under ultra-long discharge distances is conducted.On the basis of a “main vessel+booster pump vessel” combination mode and construction data from similar soil conditions in Northern Chinese ports,the variation patterns of discharge pressure with filling distance under 16 different combinations are analyzed.A critical value model for the maximum spacing and minimum spacing between the booster pump vessel and the main vessel is built,with pump inlet pressure and total discharge pressure loss as boundary conditions.A universal calculation formula applicable to different combinations and filling distances is derived.Rapid calculation of the optimal vessel layout distance on the basis of soil conditions is achieved.During construction,intelligent control of the cutter is implemented to stabilize slurry concentration at around 25%,and a “6+1” steel pipe-rubber sleeve combination is adopted to reduce local resistance losses.After systematic optimization,the pump inlet pressure of the booster pump vessel in the project's ultra-long distance clay transport conditions is increased by approximately 77.8%.The findings establish a reusable calculation model for vessel positioning in long-distance clay dredging construction,providing a reliable design basis and technical references for projects with similar geological and operational conditions.