Hull form reconstruction from insufficient data conforming to hydrostatic constraints

Classification societies perform stability analysis based on offsets submitted by shipyards and verify the results. However, in many practical situations, the hull form data required for hydrostatic evaluation is insufficient. This commonly occurs during the stability reassessment of retrofitted or damaged ships, or when original design data are limited due to confidentiality or unavailable from foreign shipyards. As a result, classification societies are often required to reconstruct the hull form using only partial information. To address this issue this study proposes a reverse-engineering method that regenerates hull forms by introducing a novel interpolation approach with area constraints so that hydrostatic requirements are inherently satisfied. Specifically, waterlines are generated at each draft level with their area constrained to match the and this guarantees the correct displacement. By maintaining waterline consistency across drafts additional hydrostatic constraints such as the , , are simultaneously satisfied. This mathematically grounded perspective that treats the -based area as a governing constraint provides a new way to couple hydrostatic data with geometric reconstruction and move beyond manual adjustments. The proposed method was validated on three ship types, and the results demonstrated its effectiveness in producing reliable hull forms for performance analysis while significantly reducing both time and dependency on expert judgment. • This study proposes a reverse-engineering method to reconstruct hull forms from coarse geometry. • Waterlines are generated at each level with their area constrained to match the waterplane coefficient ( ). • To suppress wiggles, section lines are optimized by minimizing fairness and constraint terms, resulting in smooth and realistic curves. • Validated on a container ship, a bulk carrier, and a twin-skeg hull form, confirming that the hydrostatic data ( , , , ).