An empirical identification of a representative case of ship grounding in Swedish waters and estimation of resultant consequences

The study examines grounding risk in Swedish waters using a multi-source, exposure-based analytical framework integrating accident data from Transportstyrelsen with operational activity data that the Swedish National Road and Transport Research Institute, VTI calculated based on HELCOM’s AIS data and supplementary environmental and economic datasets. The analysis is based on 292 grounding incidents involving passenger ships, dry cargo ships and tankers over the period 2011-2023. Grounding frequency, exposure-normalised rates and consequence profiles are assessed to identify underlying risk patterns and representative scenarios. Results show that grounding incidents are concentrated in coastal and archipelagic areas and are dominated by passenger ships, which show consistently higher grounding rates relative to distance travelled, operational time and fleet size. Dry cargo ships display lower and more stable rates, indicating grounding occurrence proportional to operational exposure. While most incidents result in minor consequences, insurance data reveal increasing claim severity over time. Tanker groundings, although rare, represent the highest potential for severe environmental and economic impact. The findings demonstrate a difference between grounding frequency and consequence severity, highlighting the limitations of relying only on absolute accident counts. By integrating exposure-based metrics with consequence analysis, the study provides a strong assessment of grounding risk. The results support the need for differentiated risk management strategies targeting high-frequency operational risks in coastal waters and preparedness for low-probability, high-impact events in environmentally sensitive regions.