Limitations and Practical Applicability of SEMIS Methodology in Intact Stability Assessment

This paper applies the SEMIS (Simple Evaluation Methodology for Intact Stability) approach to a 13593 DWT general cargo vessel for stability assessment using only metacentric height (GM). SEMIS estimate key stability parameters through regression models and compares them with IMO Intact Stability Code criteria. Analysis of 1314 loading conditions of investigated ship shows that SEMIS method provides quick and generally accurate evaluations of stability for typical GM ranges (GM>0.30 m). However, results reveal notable discrepancies for low-GM states (GM<0.30 m) especially in context of weather-related criteria. SEMIS in low GM condition may incorrectly classify compliance and may underestimate critical stability parameters. These findings indicate that while SEMIS is a practical supplementary tool, its application should be limited to preliminary checks rather than final compliance verification. Additionally, we can determine the GM value associated with the critical weather criterion. At this point, the b/a ratio reaches its peak, while for lower GM values it decreases significantly, remaining a nonlinear function alongside other stability parameters.