Ship-Berth Link Performance Measures in Sea Port Terminals - General Analytical Approach

The ship-berth link is one of the most important links in both the seaport terminals and the inland port terminals. As it is known, the ship-berth link capacity and throughput depend directly on the ship inter-arrival time intervals distribution, the size of ships, the kind and variable groups of cargo, ship service time distribution at berths and other traits of ship and terminal as a whole system. The service of a ship depends on the productivity of the cargo handling equipment and immediate states of all other terminal links and nodes (storage area, receiving and delivery system, etc.) in given terminals. Theoretical optimal capacity and throughput of ship-berth link, same as the whole terminal, could be found with the help of different analytical and experimental methods. However, in the practice and for real cases of terminal operations, the ship-berth link throughput performance is not most often equivalent to optimal throughput according to the expectation of port authorities and terminal operators. On the other hand, there are differences between a seaport and an inland port in ship arrival patterns within the ship-berth link. Single ships are predominant in seaports and they arrive with different sizes of loads in some time periods. Moreover, these variable groups of loads require single service. In an inland port/terminal, the kinds of arriving ships can be in the form of single ships and in groups (batches or bulk) as pushed or pulled tows of barges. Also, predominantly each barge requires single service at a berth within the terminal. In both cases, there is an analogy between the arrivals in variable groups of loads and the number of barges in tow. It means that the methodologies for the determination of ship-berth link capacity and throughput have to take into account these differences of ship arrival patterns in sea and inland terminals.