Pronounced flexibility of modern container ships can cause falling into resonance with the encounter frequencies of ordinary sea spectrum causing consequently the occurrence of springing. In order to adequately capture such physical phenomena, hydroelasticity methodology for ship structure design has to be applied including the proper definition of the restoring stiffness, being one of the main hydroelastic analysis components. This paper deals with three current restoring stiffness formulations – the consistent one with distributed mass, the consistent one with lumped masses, and the complete one. Formulation of the restoring stiffness via the finite element method is developed as a very useful approach for practical utilization of the hydroelasticity methodology. The validity of the new developed approach is checked on the case of a regular barge. The hydroelasticity of one real life container ship is evaluated and the influence of different restoring stiffness formulations is considered
