Intact stability analysis of an Aframax Tanker Vessel

In this study, an intact stability analysis of an Aframax tanker vessel was performed to address stability-related risks under different operational loads. The research focused on evaluating stability performance, IMO compliance, and the significant impact of free surface effects (FSE). These are areas often oversimplified in previous studies. Unlike earlier works, this research integrated computational modeling with empirical operational data, creating a coupled framework that simultaneously analyzes wave-tanker interactions and hull deformations, which is a gap identified in recent literature. Results indicated the ballast condition had the highest effective metacentric height (GM) of 2.90m, maximum righting lever (GZ) of 2.42m, and dynamic stability ratio of 1.48. The partial load condition was most affected by the impact FSE, causing a 17.7% reduction in GM (from 3.45m to 2.84m) and a 14.3% decrease in righting energy. All loading conditions exceeded IMO A.749 (18) criteria, with the ballast condition surpassing the minimum required area under the GZ curve (0–40°) by over 48%. The full load condition, while compliant, showed the lowest stability margins. This study provides a validated, operational stability framework that supports real-time decision-making and tank management. Recommendations include optimizing tank-filling sequences to reduce FSE, implementing condition-specific speed and wave height limits, and enhancing crew training. These findings contribute directly to improved maritime safety, operational guidelines, and vessel design standards.