ABSTRACT An improved depth-contour points generation algorithm under navigation safety constraints based on possible shallowest sounding and interpolation is proposed. An improved brain storm optimisation (BSO) for ship path planning with grounding alert using interpolated Delaunay triangulation is designed. The initial clustering centre selection method is improved to overcome the sensitivity of the initial value generated by the k-means algorithm. The clustering algorithm of the random walking centroid is used to improve the efficiency, stability, randomness, and diversity of the iterative process and prevents convergence to the local optimal solution. The tide height with grounding alert is considered in path planning to ensure that real-time water depth is deeper than the safe water depth threshold. The curve interpolation method is used for points protruding into shallow water, while the linear interpolation method is used for points protruding into deep water.