<p>Damage to the ship can threaten its overall strength, which in turn affects the structural safety of the hull and its subsequent use. Recognizing ongoing damage immediately and effectively is crucial. This paper examines a method based on curvature modes to identify ship damage. The effectiveness of this method is investigated when the ship experiences simultaneous and successive damage. The ship is simplified as a hull girder with free boundary conditions. Six different damage cases are analyzed through numerical simulations and experiments. Results show that the curvature mode index can effectively identify two separate damages when the ship is damaged in two locations simultaneously. Additionally, when the ship is subjected to continuous attacks, the curvature mode index can accurately detect new damage without being affected by existing damage. The proposed method offers a novel approach to double damage identification in hull girders, providing valuable insights for real-time ship safety assessment.</p>