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

• Only 1.77 % of vessels arrived exactly on time at Sines over 15 years. • The Container Terminal exhibits more extreme delays, with distribution skewed beyond ± 100 h. • Vessel familiarity and cargo type influence punctuality, with time-sensitive cargo performing better. • The port experiences significant issues with vessel arrival predictability, with over 14% arriving with delays exceeding one day, highlighting systemic coordination and forecasting gaps. • The variables with the greatest impact on arrivals are the number of ETAs and the continent of the port from which vessels last departed prior to arriving in Sines. 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.