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.
Maritime security in the Gulf of Guinea is a challenge that straddles multiple players and sectors, and crimes like piracy cause disruptions to international trade and shipping. During the COVID-19 pandemic, the global shipping industry tried to keep maritime security on the agenda, while advocating for global security assemblages, specifically, transnational policing initiatives as part of the maritime security governance. Using the notion of narratives and assemblage thinking, it is argued that although global shipping and Ghanaian state agents agree on the problem, they differ on which maritime security governance infrastructure to deploy, resulting in tensions between the two parties.
This work extends an existing seakeeping tool (OceanWave3D-seakeeping) to allow for the efficient and accurate evaluation of the hydroelastic response of large flexible ships sailing in waves. OceanWave3D-seakeeping solves the linearized potential flow problem using high-order finite differences on overlapping curvilinear body-fitted grids. Generalized modes are introduced to capture the flexural responses at both zero and non-zero forward speed, but we focus on the zero speed case here. The implementation of the hydroelastic solution is validated against experimental measurements and reference numerical solutions for three test cases. The ship girder is approximated by an Euler–Bernoulli beam, so only elastic bending deformation is considered and sheer effects are neglected. Some controversy has long existed in the literature about the correct form of the linearized hydrostatic stiffness terms for flexible modes, with Newman (1994) and Malenica and Bigot (2020) arriving at different forms. We provide here a complete derivation of both forms (including the gravitational terms) and demonstrate the equivalence of the buoyancy terms for pure elastic motions.
This paper presents an assessment of the energy harvesting potential from wave-induced motions when producing electricity by linear generators installed on ships. The study estimates an upper maximum energy extraction potential by not considering the electro-mechanical coupling; neither is mechanical and electrical dissipation considered. The analysis of the harvested energy is made using simulated data in a case study investigating three different ships (by size). Specifically, the case study reveals that, in moderate to mildly severe sea states, the power harvested from the environment using linear generators may reach values around 1–2 kW/tons of seismic mass. Thus, it is unrealistic to imagine ship designs where linear generators are thought to provide a ship's necessary propulsion power but, on the other hand, they may serve to supplement the main engine for auxiliary power generation.
Background: Autonomous ships have the potential to increase operational efficiency and reduce carbon footprints through technology and innovation. However, there is no comprehensive literature review of all the different types of papers related to autonomous ships, especially with regard to their integration with ports. This paper takes a systematic review approach to extract and summarize the main topics related to autonomous ships in the fields of container shipping and port management. Methods: A machine learning method is used to extract the main topics from more than 2000 journal publications indexed in WoS and Scopus. Results: The research findings highlight key issues related to technology, cybersecurity, data governance, regulations, and legal frameworks, providing a different perspective compared to human manual reviews of papers. Conclusions: Our search results confirm several recommendations. First, from a technological perspective, it is advised to increase support for the research and development of autonomous underwater vehicles and unmanned aerial vehicles, establish safety standards, mandate testing of wave model evaluation systems, and promote international standardization. Second, from a cyber–physical systems perspective, efforts should be made to strengthen logistics and supply chains for autonomous ships, establish data governance protocols, enforce strict control over IoT device data, and strengthen cybersecurity measures. Third, from an environmental perspective, measures should be implemented to address the environmental impact of autonomous ships. This can be achieved by promoting international agreements from a global societal standpoint and clarifying the legal framework regarding liability in the event of accidents.
The International Maritime Organization employs technical and operational indicators to assess ship energy efficiency. Weather conditions significantly impact ship fuel consumption during voyages, necessitating the consideration of this influence in energy efficiency calculations. This study aims to design models for estimating the impact of weather components on fuel consumption and develop correction factors to cope with the weather effect on the fuel consumption of container ships for different sea states. Using model-based machine learning, the study analyzes noon reports and hindcasted weather data from two sister container ships. It quantifies weather-induced fuel consumption across various sea states, ranging from 2% to 20%, with an average of 7%–13% depending on the model used. Correction factors specific to each sea state are derived, and different approaches for their integration into energy efficiency indicators are proposed. This study advocates tailored weather correction factors for energy efficiency metrics tied to specific sea states, emphasizing the need for standardized weather impact assessments. Prior to any formal policy application, future work is needed to address the limitations of the present study and extend this approach to various ship types and sizes and different geographical regions.
This paper presents an assessment of three methods used for sea state estimation via the wave buoy analogy, where measured ship responses are processed. The three methods all rely on Machine Learning exclusively but they have different output; Method 1 provides bulk parameters, Method 2 yields a point wave spectrum and the wave direction, while Method 3 gives the directional wave spectrum in non-parametric form. The assessment is made using full-scale data from an in-service container ship in cross-Atlantic service. Training and testing of the methods are made using data from a wave radar, and the three methods perform well. An uncertainty measure, equivalently, a trust level indicator, based on the variation between the post-processed outputs of the methods is proposed, and this facilitates determination of estimates with small errors; without knowing the ground truth.
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.
The effectiveness of fouling release coatings (FRCs) may diminish over time in the seawater. Underwater cleaning of FRCs in service is crucial for biofouling control. This study investigated the effects of cleaning parameters (brush moving speed, cleaning force and frequency) on a silicone-based FRC (SiFR) aged for 2 months (A2-SiFR) and 13 months (A13-SiFR), simulating the short-term and long-term FRCs in service. Fouling resistance, re-fouling and cleaning efficiency utilizing a self-designed automated underwater cleaning system (AUCS) were examined. Moreover, coating surface characterization, including visual appearance condition, roughness, water contact angle were evaluated on the testing surfaces. Field testing at the CoaST Maritime Test Centre (CMTC) demonstrated that underwater cleaning exhibited positive effect on the long-term fouling control performance of aged FRCs. Besides, stronger cleaning force, slower moving speed and biweekly cleaning led to better fouling resistance. No significant damages were observed on A2-SiFR surface, while regular spiral and circular scratches appeared on A13-SiFR surface. The damages led to adverse effects on fouling resistance, re-fouling and cleaning efficiency of algae on the cleaned A13-SiFR surface, affecting the coating performance more than cleaning parameters. Despite these damages, the cleaned surfaces still exhibited a higher fouling resistance compared with the ones without cleaning.
Antifouling properties of unmodified kraft lignin for potential use in marine coatings were investigated. The study was based on preliminary findings that pointed toward lignin’s efficacy against seawater organisms during laboratory tests. Coatings were formulated that contained lignin as a filler and had a pigment volume concentration above the critical pigment volume concentration. This ensured direct interaction between lignin and seawater organisms, as the lignin particles remained incompletely wetted by the binder. Moreover, all formulations were waterborne to mitigate the release of volatile organic compounds. Despite the initial promise, the antifouling performance of the formulated lignin coatings during field experiments at the CoaST Maritime Test Center was limited, and the anticipated mechanism must be reconsidered. Additionally, it was found that high lignin concentrations, while facilitating organism interaction, compromised the coating's mechanical properties. Nevertheless, the waterborne coating formulation introduced here might provide a foundation for other researchers to further investigate lignin’s potential as a bio-based pigment or a filler in coatings.