This study examines the hydrodynamic loads affecting semi-displacement vessels, particularly the influence of slamming and whipping on global hull girder strength. As vessel speeds increase, dynamic lift supports a portion of the hull, facilitating entry into the semi-displacement speed regime. While potential flow codes are commonly used for motion and load predictions, they fail to account for viscous dynamic lift, limiting their effectiveness at higher speeds. Hydroelastic experiments and Computational Fluid Dynamics (CFD) offer high-fidelity solutions but are often cost-prohibitive. To address this gap, the authors investigate the effect of adjusting vessel sinkage and trim in potential flow models based on physical model test data. Two numerical simulations—one unmodified and one incorporating trim tabs and fins—were compared across three Froude numbers (Fr = 0.25, 0.45, and 0.75) representing displacement, semi-displacement, and semi-planing regimes. This paper presents a qualitative comparison of motions, and vertical bending moments. The findings contribute to improving hydrodynamic load predictions and optimizing semi-displacement vessel designs for higher speeds and structural efficiency.