Hull form optimization with a new three-dimensional deformation strategy

As a variant of the Lackenby method, the shifting method is widely used for global geometric deformation in hull form optimization. However, similar to the traditional approach, it is confined to longitudinal transformations, limiting adjustments in beam or draft, particularly for complex geometries like bulbous bows. Its effectiveness also diminishes when hull sections exhibit minimal longitudinal variation. To overcome these limitations, this paper proposes a three-dimensional shifting method enabling deformation in length, beam, and draft directions, with numerical validation confirming feasibility. Subsequently, an efficient Computational Fluid Dynamics (CFD)-based optimization minimizes the total calm-water resistance of the Series 60 hull at Froude number equal to 0.3. Combining four deformation parameters from the three-dimensional shifting method and a Kriging surrogate model built via Sobol sampling, the optimal hull can be obtained by a single-objective genetic algorithm. Results demonstrate that the proposed method achieves comprehensive three-dimensional deformation control with few variables, yielding a 7.3% reduction in total resistance.