SPAC to Improve Port Performance for Seaports with Very Long One-Way Entrance Channels

Abstract

Very long one-way traffic (VLOWT) entrance channels have become bottlenecks for China’s seaports. However, the high costs and complexity of channel expansion make it impractical to expand a typical channel to a two-way traffic channel. Therefore, to improve port performance a ships-passing anchorage (SPAC) is proposed, which provides a temporary mooring for lower-priority ships to wait until other ships traveling in the opposite direction pass beyond the SPAC. To explore the feasibility of building a SPAC and to determine its dimensions, the annual average turnaround time, average waiting time, and average waiting time/average service time ratio were chosen as the performance measures of port service. Then, considering randomness and dynamics in ship operations, a model to simulate ships moving in and out of a harbor through a VLOWT channel with a SPAC was developed, and the port performance was calculated. Finally, the proposed model was applied to a cargo-import port with a VLOWT channel. The results show that a SPAC improves port performance and effectively saves dredging costs, and that the simulation model is an efficient tool to determine proper SPAC design.