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

Methods The boundary integral equation is discretized and solved using the Kelvin source Green's function. Numerical computations of wave-making resistance, sinkage, trim, and free-surface elevation are performed for the Wigley and S60 hull forms using a self-developed Fortran program. The results are compared with experimental data and other numerical results to analyze the effects of waterline integration and different computational approaches. Furthermore, taking the KCS container ship as an example, this study examines the differences in grid sensitivity and computational accuracy between the pressure integration method and the wave pattern analysis method when calculating the wave-making resistance of hulls with complex geometries.

Results The results show that omitting the waterline integration term in the NK theory yields reasonably accurate predictions, with significantly improved applicability at medium to high speeds. The wave patterns along the hull sides exhibit low sensitivity to grid density, enabling convergent results to be achieved 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 computational costs.

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