Over the past two decades, a number of methods have been proposed for solving maritime collision avoidance problems. Most of these works take a single ship's perspective and focus on one-to-one or one-to-many situations. To more complicated many-to-many situations, less attention has been paid. To deal with the many-to-many collision avoidance problem, this paper proposes a distributed coordination strategy which consists of two phases: firstly, predictions of ship trajectories are made based on ship dynamics, giving different candidate rudder angles, and potential collision risks that may be caused by each rudder angle selection are evaluated based on calculations of collision risk parameters; secondly, an optimization strategy is adopted to find the most efficient collision avoidance plan for the ships, namely, the rudder angles that each ship should take, and the corresponding operation time for rudder steering, with the overall objective to minimize the sum of time that each ship spends in avoiding collisions with the other ships. Simulation experiments are carried out to evaluate the effectiveness of the proposed method, as well as the corresponding communication and computation costs.

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The performance of ship rudders affects ship maneuvering, including, but not limited to, turning ability, yaw checking ability, and course-keeping ability. Previous empirical formulas for the rudder forces did not properly address the impacts of the rudder profile and the interaction between rudders in case there are more than one. To take these factors into account during the selection of rudder configurations, the regression formulas of rudder hydrodynamics that were formulated based on a series of RANS simulations and presented by Liu et al. (2016, 2017b) are applied in this study. With a more accurate estimation of rudder hydrodynamic coefficients, the impacts of rudder configurations on ship maneuvering and resistance are studied with an integrated mathematical model introduced by Liu et al. (2017a) through maneuvering simulations. The impacts of rudder configurations, more specifically rudder profiles, the spacing between twin rudders, and the spacing among quadruple rudders, on ship maneuvering and resistance are summarized. This can be used as a guide for designers to quickly assess their design choices. Accordingly, a design flow is proposed for naval architects to choose a proper rudder configuration, especially for large seagoing ships and inland vessels which commonly have multiple-rudder configurations.@en

With the trend towards less-polluting and sustainable transport solutions, the European Commission aims to strengthen the competitive position of inland waterway transport, and to facilitate its integration into synchromodal logistic chains. To stimulate inland waterway transport, it is essential to ensure smooth containers transshipments from seaports to hinterland and vice versa. Currently, inland vessels usually spend unnecessary long times in the port area due to insufficient terminal and quay planning with respect to the sailing schedules of the vessels. Coordination among multiple vessel operators and multiple terminal operators is required in order to improve the efficiency and reliability of inland waterway transport within the port. For this, four recently proposed classes of coordination strategies from our earlier work are reviewed. Two levels of cooperativeness, including partially-cooperative and fully-cooperative, as well as two types of interaction, including single-level and multi-levels are considered. The proposed coordination strategies are compared and evaluated from a methodological perspective and from an information needs perspective. Our results provide insights for vessel and terminal operators in the ways in which they can cooperate with each other: vessel operators can decide to what extent they would like to coordinate their actions based on the information requirements of each coordination strategy; terminal operators can estimate information that should be made available during different coordination phases. Moreover, our results also provide insights for policy makers or practitioners to determine the most suitable coordination strategy under different circumstances.@en

Inland vessels are often used to transport containers between large seaports and the hinterland. Each time a vessel arrives in such a port, it typically visits several terminals to load and unload containers. In the Port of Rotterdam, the largest port in Europe, there are 77,000 inland vessels that have moored in the port in 2014 for transporting cargo. With the significant growth of containerized cargo transportation over the last decade, large seaports are under pressure to ensure high handling efficiency. Due to this development and the limited capacity at terminals, the inland vessels usually spend longer time in the port that originally planned. This leads to low utilization of terminal resources and congestion in the port. This paper proposes a novel two-phase planning approach that could improve this, taking into account several practical constraints. Specifically, we take into account the restricted opening times of terminals, the priority of sea-going vessels, and the different terminal capacities and sizes. In addition, we also consider the option for inland vessels to carry out additional inter-terminal transport tasks. Our approach is based on the integration of mixed-integer programming (MIP) and constraint programming (CP) to generate rotation plans for inland vessels. In the first phase, a single vessel optimization problem is solved using MIP. In the second phase, a multiple vessel coordination problem is formulated using CP; three large neighborhood search (LNS)-based heuristics are proposed to solve the problem. Simulation experiments show that the proposed LNS-based heuristic outperforms the performance obtained with a state-of-the-art commercial CP solvers both regarding the solution quality and the computation time. Moreover, the simulation results indicate significant improvements with shorter departure times, sojourn times and waiting times.

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This paper addresses two coordination problems that exist in the waterborne transport in large seaports, the long time of stay of inland vessels and insufficient terminal and quay crane planning with respect to their sailing schedules. A novel coordination model is proposed and tackled using logic-based Benders decomposition and Large Neighborhood Search. In addition, a closed-loop perspective is taken, in which possible disturbances that may occur are considered. Simulation results show that our approach can scale to real-world sizes and provide better schedules for inland vessels within the port. The potential of using inland vessels for inter-terminal transport is also extensively investigated.

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During the past decade, inland vessels have gained importance in container transport because of their reliability, low environmental impact, and major capacity for increased exploitation. Although inland vessels are crucial in container transport between terminals in the port and the hinterland, in a large seaport like the one in Rotterdam, Netherlands, only 62% of the inland vessels leave the port on time. The other vessels have to stay in the port area for a longer time than planned. This situation leads to uncertainty in waiting times of vessels at terminals and low utilization of terminal quay resources. A two-phase approach is proposed that integrates mixed-integer programming (MIP) and constraint programming (CP) to solve the problem by generating optimal rotation plans for inland vessels. In the first phase, the single-vessel optimization problem is formulated on the basis of MIP and solved with state-of-the-art MIP solvers. In the second phase, the multiple-vessel coordination problem is formulated on the basis of CP, and a large neighborhood search–based heuristic is proposed to solve the problem. Commercial CP solvers are also used for comparison. Simulation results show that the proposed large neighborhood search–based heuristic outperforms the commercial CP solver with regard to both the solution quality and the computation time. Moreover, simulation results with respect to departure time of the last vessel, total sojourn time, and waiting time show significant improvement with earlier departure times and shorter sojourn times and waiting times.@en

Large seaports usually contain multiple terminals serving container vessels, railways, trucks and other modes of hinterland transportation. Every time an inland vessel enters a seaport, it visits several terminals for loading and unloading containers. A vessel rotation is the sequence in which a vessel visits the different terminals in a large seaport. Currently, in a seaport like the port of Rotterdam, around 40 % of the inland vessels have to spend a longer time in the port area than originally planned, due to the low utilization of terminal quay resources and uncertainty of waiting times at different terminals. To better utilize the terminal resources in the ports, as well as to reduce the amount of time inland vessels spend in the port area, this paper first proposes a new model in which inland vessels coordinate with each other with respect to the arrival, departure time and the number of inter-terminal containers carried, besides their conventional hinterland containers, with the aim to prevent possible conflicts of their rotations. Then, a logic-based Benders’ decomposition approach is proposed to minimize the total time the inland vessels spent in the port. We compare the performance of the proposed approach with the performance of a centralized approach on the aspects of the runtime, solution quality, and three logistical performance indicators. Simulation results show that the proposed approach generates both faster optimal and faster high-quality solutions than the centralized approach in both small and large problem instance.@en

Seaports are crucial nodes in international trade and transport. Some of the cargoes arriving at seaports are transshipped to other ports, while others are transported to inland destinations. Every time an inland container vessel enters the port, it calls at many different terminals spread over the port area. Two coordination problems exist in the planning of inland vessels in large seaports: firstly, the long stay in the port and secondly, the insufficient terminal and quay planning with respect to the sailing schedules of sea-going vessels and inland vessels. To solve these problems, this thesis aims to improve the reliability and efficiency of inland vessel transport in seaports. To achieve this, efficient handling of inland container vessels in large seaports is required. This could improve the efficiency and reliability of inland waterway transport from seaports to hinterland and vice versa. Meanwhile, this could also contribute to enhancing of the inter-terminal transport in large seaports, as a potential solution for alleviating congestion on roads. Moreover, efficient handling of inland vessels could facilitate flexible planning of transport over water, so that this transport mode can be better integrated into the synchromodal transport chain. Therefore, three classes of automatic coordination methods are proposed in this thesis for seaports with different sizes: for small seaports, a partially-cooperative coordination method with single-level interaction based on distributed constraint optimization is proposed; for medium-sized seaports, a partially-cooperative coordination method with multi-level interactions based on MIP, coordination rules and constraint programming, is proposed; for large seaports, a fully-cooperative coordination method with multi-level interactions based on Benders decomposition and large neighborhood search is proposed. With the proposed methods, firstly, the vessel operators can decide to what extent they would like to be coordinated, either partially-cooperative or fully-cooperative; secondly, terminal operators can also use these methods to estimate how much time each inland vessels spends at the terminal, in order to determine the schedules of terminal operations; thirdly, whenever real-time disturbances or accidents happen, the previously generated rotations might be no longer optimal, the proposed methods can take into account these disturbances and generate new and better rotations for vessel operators based on the up-to-date information. Simulation results demonstrate that the proposed approach can significantly reduce the round-trip time the inland vessels spend in the port, as well as reducing the time they spend waiting at container terminals. Moreover, from the perspective of using inland vessels also for inter-terminal transport (ITT) in seaports, vessel operators can use the proposed methods to decide whether they are willing to cooperate to take extra ITT containers based on the possible extra round-trip time and waiting time that they may spend. Moreover, terminal operators can also estimate how much extra ITT containers could be transported by the incoming vessels during different times of a day, so that they can plan the ITT containers to be transported by inland vessels accordingly. To conclude, this thesis investigates the operational planning of inland vessels in seaports. This thesis shows the potential of the proposed new approaches for improving the efficiency and reliability of inland vessel transport in seaports.@en