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To meet the specific depth requirements for laying cables in wind power projects, a new kind of undersea jetting sled has been designed. This jetting sled uses hydraulic scouring for soil penetration. The paper uses numerical simulation to compute the flow field within a specified trench and analyzes the soil penetration ability of the jetting sled by examining the distribution of shear stress on the trench walls. Initially, a single-phase flow model is used to calculate four steady flow conditions at different distances between the jetting sled and the front wall of the trench. The results reveal that as the distance increases, the area of the front trench wall affected by shear stress significantly reduces, with the top area being particularly resistant to damage. However, the soil at the bottom of the trench continues to be affected by the converging flow. Further calculations were carried out on steady flow conditions at 4 different distances for 2 different nozzle installation angles. The results show that as the angle increases, the efficiency of shear damage on the front trench wall increases. Lastly, 2 unsteady flow conditions were simulated to observe the changes in the pathline within the trench and to determine the time it takes for the flow field to achieve dynamic equilibrium. This information is used to estimate the operational speed of the jetting sled. The simulation results suggest that the jetting sled is capable of excavating a trench of the specified depth at an operational speed of 900 meters per hour.