A numerical analysis is tried how the “waves” and “boundary layer-wake” interacts. External potential flow around a hull is modeled by modified Guilloton method. Viscous flow is modeled by integral boundary layer-wake method. The displacement thickness concept is used to match the viscid-inviscid calculations. Results are compared with experiments and followings are obtained. Stern wave generation and boundary layer-wake growth depend on Froude number. The displacement thickness aft of the stern end increases and the wave resistance reduction due to the boundary layer-wake is remarkable at the speed from hollow to hump.