The paper employs the Second Generation Intact Stability Criteria (SGISC) Vulnerability level 2 to investigate the vulnerability of the MARIN series of fast displacement ships to surf-riding. Additionally, the paper examines the influence of different options for ship resistance and wave surge force calculation on the outcome of the vulnerability assessment. The results indicated the limiting size of the ships in the series for which the surf-riding became the design constraint. Furthermore, it is shown that while the ship resistance estimation method might not have a considerable influence on the surf-riding vulnerability assessment, the impact of accounting for effects of diffraction in the wave surge force could be significant.