<p>Herein, we investigate the effect of cracks at cutouts at the intersections of longitudinal stiffeners and transverse frames in ship hull structures on their fatigue life. In particular, we investigate the effects of the cutout geometry, crack location, initial crack length, and crack orientation on fatigue life by conducting numerical simulations. Initially, we analyzed a large-scale panel (4 800 × 9 600 mm) with transverse frames and stiffeners containing cutouts under hydrostatic pressure; in the analysis, we employed shell elements to identify the stress concentration zones. Subsequently, we developed a detailed 3D solid-element model and simulated crack propagation based on Paris’ law using the extended finite element method (XFEM) implemented in ANSYS software. The simulation results were validated using existing numerical and experimental data to ensure accuracy. Our results showed that for the same crack length and force applied to various hull frame cutouts, the obtained fatigue lives were different; this is attributed to the complex stress distribution around cutouts. Additionally, the orientation and location of cracks significantly affect the crack growth rate. These findings indicate the need for design modifications to mitigate stress concentration and improve the durability of ship structures.</p>