We consider the Tramp Ship Routing and Scheduling Problem (TSRSP) in which we plan routes for a fleet of tramp shipping vessels operating on a combined contract and spot market. Earlier research has been fragmented due to variations in the side constraints studied. Hence we present the first unified model that can handle speed optimization, chartering costs, bunker planning, and hull cleaning. The model is solved by column generation, where the columns represent the possible routes of a vessel, while the master problem keeps track of the binding constraints. The pricing problem is solved efficiently using a time–space graph and several dominance rules. Real-life instances with up to 40 vessels, 35 geographic regions, and four months planning horizon can be solved to optimality in less than half an hour. The optimized routes increase earnings by 7% compared to historical schedules. Furthermore, policy-makers can use the model as a simulation of a rational agent behavior.
A multidisciplinary and -national team of Ghanaian and Danish researchers engage in a three year research project financed by the Danish Ministry of Foreign Affairs in order to address the question how communication, gender, and sustainability affect the cluster performance of the Port of Tema in Ghana. We approach the question from different angles ranging from quantitative survey datat to longitudinal anthropological observations and qualitative multilayered interviews with port workers, politicians, port officials, domestic and foreign investors, and representatives from the surrounding communities.
Due to limited access to domain knowledge and domain-relevant benchmark data, the Container Stowage Planning Problem (CSPP) is notably under-researched. In particular, previous models of the CSPP have lacked two key aspects of the problem: lashing forces and paired block stowage. The former may reduce vessel capacity by up to 10%, and the latter is NP-hard. The Representative CSPP (RCSPP), which captures all critical aspects of the problem is formulated. The presented RCSPP incorporates overlooked constraints such as paired block stowage and lashing, along with an innovative method for estimating lashing forces, all while maintaining simplicity. A heuristic method, STOW, has been developed to identify solutions for the RCSPP using a specially designed benchmark suite based on real-world scenarios. STOW algorithm is an advanced search heuristic employing a diverse range of solution modification strategies, each tailored to address specific aspects of stowage optimization. Feasible solutions were successfully identified for all instances within the benchmark suite. Our initial findings emphasize the importance of accurately modeling lashing forces and employing paired block stowage. Results show that removing the lashing constraint can increase the number of containers stowed by over 7% on average, while disabling paired block stowage can result in nearly a 5% increase.
Danish seine is an active fishing gear targeting demersal species, such as European plaice (Pleuronectes platessa, hencefort referred as plaice), a commercially important fish species in the North Sea, Skagerrak, Kattegat, and Baltic Sea. Danish seining is a relevant fishery in relation to exemption from the European Union landing obligation. Trials were conducted from a commercial fishing vessel during the summer with high air temperatures and sea salinity and marked salinity and temperature gradients (pycnocline). Video equipment was used to observe fish entering the seine. Captured fish were individually tagged and housed in livewells for ten days to observe short-term survival. Reflex impairments and external injuries were assessed after capture and at the end of the observation periods using reflex action mortality predictor (RAMP) and catch-damage index (CDI) methodologies. We found that plaice entered the seine late in the towing process and that 87 % of the assessed fish survived, after 10 days of observation. There was a significant difference in short-term survival curves for fish that had been subjected to more than 30 min of on-deck during the catch-sorting process relative to those that had remained on deck for 30 min or less. The association between the time on deck and RAMP scores after capture was also significant. External injuries were primarily minor bruises, fin fraying, and net marks and changed little from after capturing to the end of the observation period.
The interest in sustainability in the maritime industry has been on the rise. Attention has shifted from how to develop and comply with environmental regulation and labour standards to a more integrated view on sustainable maritime transport that aims at incorporating sustainability in maritime firm strategies. The liner shipping industry, which has been at the forefront, plays a crucial role in global supply chains, with its commitment to sustainable maritime container transport gaining recognition. In particular, procurement relationships stand out as an area where sustainability can exert the most significant impact. Ocean transport is among the most widely outsourced services globally both by shippers and by freight forwarders. Unlike bulk transport, container ocean transport is always outsourced, as shippers do not use their own vessels. Yet, the selection criteria that logistics firms use regarding sustainability when choosing ocean transport service providers and the role of sustainability in value creation among shippers/freight forwarders and ocean transport providers have been scarcely explored.
This article delves into value creation via quality improvement and sustainability practices in ocean freight transport. Employing a case study of an ocean carrier, alongside interviews and survey data, it explores how liner shipping companies can leverage high-quality and sustainable operations to enhance service for their clients and create logistics value. A novel aspect of this study is the application of sustainable supplier management concepts to maritime logistics, highlighting how shippers’ sustainability requirements in sourcing ocean freight services shape procurement relationships and how shipping companies can employ sustainable procurement strategies for value creation.
The Nordic countries are ranked among the most gender equal countries worldwide. Equality, political, and civil rights, leading to the high participation of women in the workforce, have paved the way for this egalitarian view. However, women remain the minority in managerial positions in general, and they are also strongly underrepresented in many male‐dominated sectors of the blue economy. The aim of this article is to introduce and discuss gender equality in the blue economy, and to assess the status of gender research in the Nordic context. To achieve this, a purposive interdisciplinary literature review resulted in three encompassing themes on how women’s participation is hindered, overlooked, and undervalued. Using these themes as an analytical lens, we propose that the underlying mechanisms are similar within fisheries, aquaculture, and maritime transportation in how they affect women’s participation. Still, there is a lack of statistics and research within parts of the blue sector. To move forward, there needs to be a shift in focus from policy to practice. One starting point could be to implement current knowledge, e.g., regarding workplace design and tailoring equipment to fit a diverse workforce. We call for scaling up best practices and evaluating policy performance and effectiveness. These are prerequisites for sustainable recruitment and retention of the blue sector workforce and the only way forward for countries aspiring to be truly gender equal.
As ocean space increasingly is used for production purposes, such as for the production of food and feed, renewable energy and resource mining, competition for space becomes a concern. A spatial solution to this is to co-locate activities in a multi-use setting. Next to the direct (financial) costs and benefits of multi-use and the societal cost and benefits, there are other factors, in the realm of legal aspects, insurance, health and safety issues and the overall governance of multi-use, that determine whether multi-use can be implemented successfully. This includes transaction costs that arise when for example non-adequate regulation, governance and insurance schemes are in place. Based on the analysis of five case studies across Europe these combined/collective transaction costs of multi-use are analysed and suggestions how to reduce and/or overcome these transaction costs are presented.
Shore power is an important green technology used by ports to reduce carbon emissions. This paper investigates how to design subsidy strategy for promoting the installation and utilization of shore power. However, while installation subsidies may promote the installation of SPI in ports, resulting in a reduction in ship emissions, utilization subsidies may attract more ship visits, which may increase the total emissions of a port. Therefore, subsidies for shore power utilization and installation should be optimized to minimize the cost to government (comprising the environmental costs of ship emissions, the cost of utilization or installation subsidies, and carbon taxes) and maximize the profit for ports (including profit from original and new ships, utilization and installation subsidies, and carbon taxes). Using the Stackelberg game methodology, we discuss five cases to give a comprehensive analysis of the design of different subsidy policies, including no subsidy, SPI-utilization subsidy undertaken by port, SPI-utilization subsidy undertaken by port and government, carbon emission tax policy considering SPI-utilization subsidy, and SPI-utilization and SPI-installation subsidies undertaken by port and government. Managerial insights are generated according to the theoretical analysis and numerical experiments results, which can give references to the government and port operators.
This study investigates how the recognition and exploitation of entrepreneurial opportunities influence small business performance via interactions with firm-level innovation capability and learning orientation. We frame the study within the maritime-sector context and seek to contribute to the understanding of how the interplay between opportunity recognition, exploitation, innovation capability and learning orientation affects the entrepreneurial performance of local businesses when there is a technological policy change. The study further frames its arguments from a dynamic capability perspective and tests its arguments with data from 284 local businesses operating in the Port of Tema. Findings reveal that opportunity exploitation and learning orientation as well as their interplay have a positive and significant effect on entrepreneurial performance. The study consequently presents local micro-entrepreneurial reactions to macro-level policy changes within the maritime sector – an issue that has largely remained uninvestigated in the African business literature due to maritime blindness.