The prediction of wave loads acting on a ship in small and moderate seas has almost become a matured technology in the field of naval architecture. However, shiploads in abnormal waves are rarely examined, both numerically and experimentally, because of the difficulty associated with the generation of the abnormal waves embedded in real deterministic waves. In this paper, a practical engineering numerical tool is used to analyse the effect of slamming and green water on the distribution of the vertical bending moment (VBM) peaks of a containership in abnormal waves. The experimental and the numerical simulations are conducted for two kinds of ship models. First one, with an extended bulwark for which no green water is observed and the second one without the extra bulwark for which severe green water shipping is observed. The numerical tool is based on a 2D time domain (TD) method, and the hydrostatic and hydrodynamic forces are calculated for instantaneous wetted surface. The radiation forces are represented by means of convolution integrals based on Cummins formulation. The hydrodynamic coefficients are also calculated for the exact wetted surface for each time instant. The ship is tested in the well-known abnormal wave ‘New Year wave’ and ‘North Alwyn wave’ for two ship speeds. The experimental results measured in the wave tank are compared with the numerical results. In order to compare the time series, the measured incident wave profile is used in the numerical simulation. © Springer Nature Singapore Pte Ltd. 2019.