Objectives A practical computational method based on Neumann-Kelvin（NK）theory is proposed for rapid calculation of wave-making resistance.

Methods The boundary integral equation is discretized and solved using the Kelvin source Green’s function. The numerical computations of wave-making resistance, sinkage, trim and freesurface elevation for the Wigley and S60 hull forms are conducted using a self-developed Fortran program. The results are compared with experimental data and other numerical results to analyze the influence of waterline integration and different calculation methods. Furthermore, taking the KCS container ship as an example, the study investigates the differences in grid sensitivity and computational accuracy when applying the pressure integration method and the wave pattern analysis method to solve the wave-making resistance for hulls with complex geometries.

Results The results show that omitting the waterline integration term in NK theory yields relatively accurate results, with significantly improved applicability at medium to high speeds. The wave patterns along the hull sides exhibit low sensitivity to grid density, allowing convergent results to be obtained with relatively coarse grids. For hulls with complex geometries, the wave pattern analysis method for calculating wave-making resistance ensures computational accuracy while significantly reducing grid requirements and lowering computational costs.

Conclusions This study provides a simplified and rapid practical tool for ship resistance evaluation and hull form optimization.