Research On Optimal Number Of Anchorage For A Port Based On Queueing Theory

With the growing volume of international transport of goods, gradually expanding the size of the port, the ship's arriving frequency is increasing. However, ships usually can not immediately be alongside as soon as they arrive at the port, usually need anchorage for some time. So a large number of anchorages are required.However, the construction of the anchorage spends a lot of navigable waters and some money, so we should construct the anchorage as little as possible when meet the port need. So, how should we take such a standard? First, we need to calculate the least number of anchorages under the normal operation of the port, which is the optimal number of the anchorages for the port. Then, Arrange the anchorage for the port, based on the optimal number of the anchorage and whether the port is going to expand, considering the special circumstances required for the ship taking refuge.In this thesis, the author established a model to calculate the optimal number of anchorages by queueing theory, based on ranking the anchorage position. According to the model to calculate the optimal number of anchorages in every rank, and then sum, the result is the optimal number of anchorage for the port. Because the different ship requires different water depth to anchor, and limited by the ship's tonnage and type, a ship can not be optional for berthing in the harbor. However, the requirement of the ship to the anchorage water depth depends on the ship's tonnage and type. Therefore, we can statistic a certain tonnage, a certain type of ships' arriving information and service time by ranking the anchorage position, and get the number of the available berth for this rank ship. Then, using those elements calculates the number of anchorage this rank ship required based on the model. Compared with using all arriving ships' information and all the berth of the port as the elements of the model, this method can minimize the error.After established the ship anchor queueing model, the author verified the model using the oil tanker and bulk chemical tanker special anchorage of Dalian Xingang. The author modified the model according to the anchorage need of the ship off the berth. Then the result is consistent with the actual.