Channel scheduling for ports

Shipping channels are often a constraint to port capacity due to the significant capital cost and environmental impact of channel dredging. Channels can be narrow in places which constrains the capability of vessels passing in opposing directions. Capacity impacts of channel operations are significant in tidally restricted ports, where deep draft vessels are only able to move through the channel during narrow windows around high-tide in order to maintain sufficient under-keel clearance. There has been much research to-date around berth allocation and sequencing, but in channel constrained ports the value of these existing approaches can be compromised. This was demonstrated during the project through discovery of specific examples where berth allocations are sub-optimal when not integrated with channel scheduling. In this project a mathematical model and associated algorithms were developed to optimise the scheduling of channel movements and furthermore, to integrate the channel scheduling and berth allocation/sequencing problems. The approach was evaluated on an extensive range of scheduling problem instances, it was successfully applied to problems of practical scale, and demonstrated savings in vessel waiting times (up to 60% in some instances) through mathematical optimisation compared with widely practiced rules of thumb.

Considering the high cost of demurrage for queuing vessels (up to AUD40,000 per day per vessel), any reduction in waiting times through schedule optimisation directly translates into significant financial benefit to port operators. Ports periodically require large CAPEX projects ranging from AUD100M to more than AUD1B to expand infrastructure in response to trade growth. Reduced waiting time translates into improved berth and channel utilisation, possibly delaying or avoiding the need for large CAPEX projects, another significant cost benefit of optimised scheduling.