Ship arrival patterns at the port of Sines: A comparative analysis of ETA and ATA

Accurate vessel arrival predictions are fundamental to efficient port operations, yet their reliability remains poorly understood. This study examines 15 years of arrival data from the Port of Sines (2009–2023) to assess the accuracy of Estimated Time of Arrival (ETA) predictions and their operational implications. The analysis of vessel movements reveals that precise on-time arrivals occurred in only 1.77 % of cases. While 56.93 % of vessels arrived ahead of schedule, delayed arrivals were disproportionately severe, averaging 6 h and 52 min late. The data shows 1,623 instances of extreme delays exceeding 24 h, highlighting significant forecasting challenges. Terminal specific analysis demonstrates marked variation in performance: The Container Terminal recorded the highest average delay (+10:26 h) and was the only facility where late arrivals outnumbered early ones. It was found that vessels with frequent port calls exhibited substantially better punctuality, indicating that operational knowledge improves scheduling accuracy. These timing discrepancies translate directly into extended anchorage periods, generating measurable economic costs and environmental impacts through increased fuel consumption and emissions. Better forecasting accuracy could significantly reduce the operational inefficiencies that currently outbreak container shipping operations.