Quantifying operational variability across ship types and size classes in the North and Baltic Seas

Kurzfassung

This study quantifies operational variability across major ship types and size classes in the North and Baltic Seas using one year of AIS data. A framework of twelve operational metrics is developed to capture key dimensions of ship operations and aggregated into variability scores at ship-type and size-class level. Results reveal clear structural differences: cargo segments such as container, vehicle, and bulk carriers exhibit low variability and highly standardized operations, while passenger and service vessels show pronounced heterogeneity. Variability generally decreases with vessel size, indicating increasing operational standardization. Decomposition analysis identifies engine performance and energy use as primary drivers of variability, followed by routing and loading, while speed plays a minor role. Sensitivity analyses confirm robustness across weighting schemes. The findings provide empirically grounded reference values for improving fleet-level emission and compliance models and support more realistic assessments of maritime decarbonization strategies.