Objectives With the gradual reduction in Arctic sea ice extent and the continuous expansion of polar shipping routes, navigation activities in high-latitude regions have increased significantly. However, polar vessels are exposed to extremely harsh environmental conditions, among which marine icing and accidental hull damage represent two of the most critical threats to navigation safety. Ice accretion on ship superstructures and decks not only increases displacement but also causes non-uniform mass distribution, leading to upward and forward shifts of the center of gravity and a substantial degradation of stability. When hull damage and subsequent flooding occur under icing conditions, the combined effects may dramatically increase the risk of capsizing. Existing studies have primarily focused on either marine icing or damaged stability independently, while systematic investigations into their coupled influence remain limited. To address this gap, this study conducts a comprehensive stability assessment of a polar vessel under combined ice accumulation and asymmetric damage conditions.

Methods An ice accretion prediction model based on spray icing theory is first established. Both wave-generated spray and wind-driven spray, which are the dominant sources of marine icing during polar navigation, are considered. The model incorporates mass conservation and energy balance principles, accounting for sensible heat flux, latent heat flux, evaporative heat flux, and radiative heat flux during the icing process. A freezing coefficient is introduced to quantify the proportion of impinging spray droplets that freeze upon impact. The DTMB 5415 ship is selected as the reference vessel. Model validation is conducted by comparing the predicted freezing coefficient with published results, showing good agreement. Parametric studies are then performed to investigate the effects of wind speed and ambient temperature on ice accretion under different icing durations (6 h, 12 h, and 18 h), which are representative of continuous severe weather conditions encountered by polar research vessels.Based on the predicted ice mass distribution, the variations in ship displacement, center of gravity, trim, and draft are calculated. Static stability analyses are carried out for both intact and damaged conditions. The ship is subdivided into 16 watertight compartments, and an asymmetric midship damage scenario involving the No.9–No.10 compartments on the starboard side is adopted. Righting arm (GZ) curves are computed to evaluate the effects of icing duration and damage on static stability, with reference to the requirements of the IMO International Code on Intact Stability. Furthermore, dynamic stability is assessed using the ultimate dynamic inclination angle, which reflects the maximum heel angle a ship can withstand under combined wind and wave excitation. The corresponding maximum allowable wind speed is determined by analyzing the dynamic stability curve with a resonance angle of 20°, in accordance with stability assessment standards.

Results The results demonstrate that wind speed and ambient temperature are the dominant factors influencing ice accretion. Ice accumulation increases almost linearly with wind speed due to enhanced spray generation and increases rapidly with decreasing temperature as the freezing coefficient approaches unity. After 6 h, 12 h, and 18 h of icing, the total ice mass reaches 700.056 t, 1 526.124 t, and 2 213.192 t, respectively, causing the ship’s center of gravity to shift significantly forward and upward. For intact ships, increasing icing duration leads to a continuous reduction in the maximum righting arm, the angle of vanishing stability, and the area under the GZ curve. The intact ship fails to satisfy IMO static stability requirements after 18 h of icing. For damaged ships, stability deterioration is more pronounced: under 12 h of icing, the maximum righting arm decreases to 0.071 m, far below the IMO criterion of 0.2 m at a heel angle of 30°.Dynamic stability analysis further reveals the severe impact of combined icing and damage. For the intact ship without icing, the ultimate dynamic inclination angle is 64.8°, corresponding to a maximum allowable wind speed of 33.1 m/s. In contrast, for the damaged ship under 6 h of icing, the ultimate dynamic inclination angle decreases to 62.1°, and the maximum allowable wind speed drops sharply to 16.0 m/s, representing a reduction of more than 50% in wind resistance capability. These results indicate that the synergistic effect of ice accumulation and hull damage significantly compromises both static and dynamic stability, posing serious risks to polar navigation safety.

Conclusions This study provides a systematic assessment framework for evaluating the stability of polar vessels under combined icing and damage conditions. The findings offer valuable references for polar ship design, operational risk assessment, and the development or revision of stability criteria for ships operating in ice-prone regions. Future work should focus on incorporating time-domain flooding processes and transient damage scenarios to further improve the accuracy and applicability of stability evaluations for polar vessels.