Search Results (1,477)

International shipping decarbonization has expanded beyond technical and operational regulation to include contested market-based bargaining. The proposed International Maritime Organization (IMO) Net-Zero Framework (NZF) combines a marine fuel standard with an economic compliance mechanism. Drawing on IMO submissions, voting records, official statements, and domestic and sectoral materials, this two-level game analysis examines why support sufficient to approve the draft for circulation in April 2025 did not translate into timely adoption later that year. The evidence suggests that the initial agreement space was not durable enough to support adoption on the planned timetable. At Level I, bargaining involved three linked dimensions: rule-making authority, responsibility allocation, and transition pathway design. At Level II, domestic, regional, and sectoral constraints included regulatory credibility and investment signals for the European Union; sovereignty and cost concerns for the United States; trade exposure and disproportionate impacts for trade-exposed emerging economies; ambition and revenue-supported transition for small island developing States; and fuel availability, fleet competitiveness, and legal certainty for energy exporters and open registries. A coalition sufficient at one procedural stage may therefore not remain sufficient at the next. A more durable agreement space would likely require an IMO-centered regulatory core, targeted enabling support, an ambition floor with compliance flexibility, and sequenced implementation and review. Full article

This paper mainly investigates the ice-impact resistance of PVC foam sandwich beams for polar ship protective structures through low-velocity impact experiments and nonlinear finite element simulations. An experimentally validated elastic–plastic coupled model, accounting for ice crushing and large structural deformation, was used to examine the effects of core density and face-sheet thickness distribution on the ice-impact response of sandwich beams. Results show that the upper face sheet undergoes local indentation and global bending, the lower face sheet mainly bends globally, and the foam core exhibits local compression and overall bending, while compressive deformation accompanied by ice crushing and spalling occurs at the front part of the ice impactor. Moreover, the effective structural stiffness decreased during plastic loading as local indentation and core compression developed, whereas the unloading stiffness was higher than the effective stiffness during plastic loading. Energy dissipation primarily comes from ice crushing, face-sheet plasticity, and core compression. Increasing core density reduces deflection and core compression but increases peak force. Among the three face-sheet configurations examined at a constant total thickness, the configuration with a thinner upper face sheet and a thicker lower face sheet produced a smaller final deformation of the lower face sheet. This study provides a useful reference for ice-resistant design of sandwich structures in polar ships. Full article

Owing to transportation, installation, grid-connection, and maintenance requirements, nearshore offshore wind farms are often located close to busy shipping routes, substantially increasing the risk of ship–offshore wind turbine (OWT) collisions. To enhance the impact resilience of OWT support structures against ship collisions, a novel honeycomb sandwich fender is proposed for tower protection. Nonlinear transient analyses were performed using ANSYS/LS-DYNA to simulate a 5000 t ship traveling at 2 m/s and colliding with a 4 MW OWT supported by a single-column tripod foundation. The effects of rubber and aluminum foam cores on the crashworthiness and protective performance of the fender were compared. The results show that the rubber core stores collision energy through recoverable large deformation and releases most of the stored energy during unloading, resulting in pronounced energy restitution and prolonged structural excitation. By contrast, the aluminum foam core dissipates 7.5 MJ through cell-wall buckling, progressive crushing, and plastic collapse, corresponding to 75% of the initial kinetic energy of the ship. Compared with the rubber-core fender, the higher initial stiffness of the aluminum foam increases the peak contact force by 23.1%, from 13.0 to 16.0 MN. However, its irreversible energy-dissipation mechanism reduces the maximum tower-top displacement by 40.0%, from 1.25 to 0.75 m, and decreases the residual tower stress after three successive collisions by 25.0%, from 200 to 150 MPa. These results demonstrate that, despite transmitting a higher peak contact force, the aluminum foam fender provides more effective overall protection under the collision conditions considered because of its greater irreversible energy-dissipation capacity. Full article

Anthropogenic noise from Australia’s expanding Blue Economy, including shipping, fishing, and offshore renewable energy development, may impact pinnipeds on land and at sea, as they rely heavily on sound for communication, environmental sensing, and predator avoidance. Effective noise management requires species-specific hearing data. We present the first aerial audiograms of two Long-nosed fur seals (Arctocephalus forsteri) between 100 Hz and 20 kHz, following a conditioned-response paradigm. Hearing tests were conducted inside an anechoic chamber at Taronga Zoo, Sydney. Both seals showed peak sensitivity at 3.2 kHz, with thresholds of 7 and 12 dB re 20 µPa. The younger female exhibited greater high-frequency sensitivity, while overall audiogram shapes were comparable to those reported for other (Northern) fur seals. Audiograms were overlain with spectra of common terrestrial noises and detection ranges were discussed. This study provides essential baseline data for developing auditory weighting functions, assessing the potential impacts of noise, and informing environmental management of coastal and offshore developments. Full article

In November 1916, the Imperial German Navy conducted an ambitious raid against the Russian forces in the Baltic Sea. With the aim of attacking Russian ships in the coastal waters of Estonia, a squadron was dispatched from Libau. The operation proved to be very costly, with seven ships sunk by Russian mines and only minimal damage caused to the port of Paldiski. In 2025, the Estonian Maritime Museum conducted a survey of three of the seven Imperial German Navy large torpedo boats sunk north of Hiiumaa island in Estonia. The aim was to identify the wrecks and determine the potential threat the wrecks may pose to the environment from the fuel oil the boats carried. The assessment was time critical as the wrecks had sunk more than a hundred years ago, and due to the location, any oil spill from the wrecks could potentially impact Estonia, Finland, and/or Sweden. The research concluded that all three surveyed wrecks could still contain substantial amounts of fuel oil, and although the wrecks are not leaking and the collapse of the wrecks is not considered imminent, the risk mitigation should be carried out as soon as possible; the possibility for successful oil removal diminishes every year as the wrecks corrode and disintegrate. Full article

Port-related maritime emissions constitute a significant source of urban air pollution and greenhouse gas emissions, particularly in rapidly developing coastal cities. Within this context, the present study quantifies ship-related emissions at the Port of Casablanca, Morocco’s largest and most strategically important port, and evaluates their associated environmental and socio-economic impacts. A bottom-up methodology was applied to estimate emissions from vessel operations between 2017 and 2021. The inventory integrates vessel characteristics, engine specifications, operational load factors, emission factors, and the duration of maneuvering and hotelling phases to estimate emissions of CO₂, SO₂, NO_x, CO, NMVOCs, PM, PM₁₀, and PM_2.5. The emission inventory was subsequently coupled with damage cost factors to assess the external costs associated with shipping emissions. The obtained results demonstrate that CO₂ was the dominant emitted pollutant, representing approximately 97% of total emissions, whereas NO_x and SO₂ accounted for 2% and 1%, respectively. Bulk carriers emerged as the principal emission source (44%), followed by container vessels (36%), with the highest emission levels observed during 2018–2019, coinciding with increased port operations. Furthermore, the integration of emission inventories with damage cost factors demonstrated that NO_x, although emitted in much smaller quantities than CO₂, exerts a disproportionately higher environmental and societal burden due to its impacts on public health and ecosystem quality. This study provides one of the first integrated bottom-up emission inventories and external cost assessments for a Moroccan port. The proposed framework supports evidence-based decision-making for sustainable port management and demonstrates the need for emission reduction strategies that simultaneously address climate change and air quality objectives. Full article

Accurate Estimated Time of Arrival (ETA) forecasting is essential for improving operational planning and decision-making in modern ports. While machine learning has significantly enhanced ETA prediction using Automatic Identification System data, the impact of data preprocessing on forecasting performance remains underexplored. This study investigates how AIS data preprocessing and machine learning model selection jointly affect ETA forecasting for short-sea shipping, using the Port of Sines as an empirical case study. A reproducible forecasting workflow was developed, integrating dataset construction, voyage selection, feature engineering, predictive modelling and performance evaluation. Three supervised machine learning algorithms, K-Nearest Neighbors, Random Forest Regression, and Multilayer Perceptron, were trained and compared under identical experimental conditions. The results show that forecasting performance depends not only on model selection but also on the quality of the modelling dataset. In particular, Random Forest Regression achieved the strongest and most consistent performance. It was found to be invariant to feature scaling, whereas scaling had a small negative effect on K-Nearest Neighbors and increased training variance for the Multilayer Perceptron. Although all three models achieved accurate ETA predictions, they exhibited different strengths regarding predictive performance, computational efficiency, and operational applicability. The proposed workflow contributes to the development of transparent and reproducible ETA forecasting methodologies and provides practical guidance for implementing AIS-based decision-support systems in short-sea port operations. Full article

To address the limited endurance of Unmanned Surface Vehicles (USVs) in time-varying sea conditions, this study investigates global energy-efficient path planning that balances obstacle avoidance and energy efficiency. First, based on ship seakeeping theory, an energy consumption model incorporating wave height, wave period, speed, and wave-encounter angle is constructed to represent the impact of dynamic sea states on resistance. The model is assessed through formula–program consistency verification, a multi-factor input ablation on a physics-constrained benchmark, and external trend validation against published towing-tank added-resistance data. Second, the planning problem is modeled as a Partially Observable Markov Decision Process (POMDP). Built upon the Soft Actor-Critic (SAC) algorithm, a Bimodal Spatio-Temporal Feature Fusion Network (BSTFN) is proposed to achieve deep fusion of spatial perception information and historical temporal sea state sequences for decision-making. Furthermore, a composite reward function is designed, integrating energy consumption penalties, heading guidance, and smoothness constraints. Simulation results demonstrate that the proposed method effectively utilizes favorable encounter angles to avoid high sea state regions. While maintaining high task success rates, it significantly reduces average energy consumption, effectively enhancing the endurance and robustness of USVs in complex dynamic environments. Full article

The structural safety of a marine remotely operated vehicle (ROV) launch and recovery system (LARS) under extreme sea conditions determines the reliability of underwater exploration. To address the susceptibility of traditional rigid frames to local yielding and dynamic instability under transient high-frequency impacts from a mother ship, this study conducts structural dynamics simulation and vibration reduction optimization for a heavy-duty ROV LARS. A spatial finite element model was established, introducing boundary conditions that decouple the static gravity field from the transient inertial mass. Mechanical responses under eight typical operating conditions were systematically evaluated. Results indicate that the rigid frame experiences significant limitations under a 1 g horizontal transient impact, with peak stress reaching 195.38 MPa and deformation exceeding 20 mm. Consequently, a non-invasive vibration reduction strategy using viscoelastic damping boundaries is proposed, alongside an equivalent buffer dynamics model. Verifications demonstrate that this flexible damping constraint prolongs collision momentum transfer time and dissipates impact kinetic energy. Post-optimization, maximum transverse and longitudinal von Mises stresses decrease by over 37%, and transient deformation is reduced by over 64%. This study addresses the weight penalty of traditional strengthening designs, providing a mechanical reference for the lightweight design and impact protection of heavy-duty marine equipment. Full article

With the rapid expansion of offshore wind farms into deeper waters, large-scale wave-compensated transfer gangways have become critical equipment for ensuring safe personnel transfer between maintenance vessels and wind turbines. However, the increased mass and inertia of large gangways introduce significant control delays in hydraulic actuation, data acquisition, and compensation calculation processes, which severely degrade compensation accuracy and threaten operational safety. This paper proposes a predictive active wave compensation control scheme based on Back Propagation (BP) neural network to address this challenge. First, a ship vertical-plane kinematic model was established to derive the mapping relationship between ship motions (roll, pitch, heave) and gangway end-point positions. The impact of 3–5 s control delays on gangway stability was systematically analyzed, revealing that uncompensated delays can cause end-point deviations exceeding 4 m. Then, an optimized BP neural network model was constructed for short-term ship six-degree-of-freedom (6-DOF) motion prediction, with key parameters (input duration, hidden layer nodes, random seed) tuned to achieve high prediction accuracy. Finally, the proposed predictive control scheme was validated through numerical simulations. The results demonstrate that the scheme can reduce the maximum end-point deviations by more than 80% for delays up to 5 s, effectively mitigating the adverse effects of control delays. This research provides a technical solution for improving the safety and reliability of large offshore transfer gangways. Full article

Maritime transport emits a range of atmospheric pollutants, including sulfur oxides (SO_x), nitrogen oxides (NO_x), particulate matter (PM), and volatile organic compounds (VOCs), which contribute to air pollution and are associated with adverse environmental and public health impacts. To mitigate these impacts, the International Maritime Organization (IMO), London, UK introduced the global sulfur cap (IMO 2020), which entered into force on 1 January 2020, limiting the sulfur content of marine fuels to 0.50% m/m. This study systematically reviews the environmental and public health impacts of shipping emissions following the implementation of IMO 2020. A systematic literature review was conducted in accordance with PRISMA 2020 guidelines using Scopus, Web of Science, PubMed, and supplementary sources. Following a structured screening process, 67 studies published between 2020 and 2025 were included and analyzed through descriptive, bibliometric, and thematic synthesis approaches. The reviewed studies consistently reported substantial reductions in sulfur dioxide (SO₂) emissions, sulfate aerosols, and shipping-related particulate matter following IMO 2020. These reductions were associated with improved air quality in major maritime and port regions and reduced population exposure to harmful pollutants. However, the reviewed evidence also identified ongoing challenges, including emissions of ultrafine particles and volatile organic compounds, secondary pollutant formation, contamination associated with scrubber washwater discharge, and reduced sulfate aerosols contributing to positive radiative forcing. Overall, the reviewed evidence suggests that sulfur-related air pollution generally declined following the entry into force of IMO 2020, although these observations should be interpreted alongside other concurrent developments that influenced global shipping activities during the study period. This review synthesizes current evidence on the environmental and public health impacts of IMO 2020, identifies emerging knowledge gaps, and provides an evidence base to support future shipping emission policies and research. Full article

Maritime transport contributes 2.9% of global greenhouse gas emissions, traditionally evaluated through operational fuel cycles while neglecting lifecycle impacts. This study redefines merchant ship recycling as a strategic front-end pillar for global decarbonization by assessing Embodied Carbon Trade-offs. Utilizing a mixed PRISMA systematic and semi-systematic methodology of literature from 2019–2025, we analyzed bulk carriers, container ships, and tankers across six thematic clusters. Our findings demonstrate that scenarios involving the potential decommissioning of up to 22.2% of the global merchant fleet exceeding 20 years of age could significantly mitigate lifecycle emissions by displacing primary iron-ore smelting with circular electric arc furnace marine-steel recovery. Crucially, this environmental dividend is non-linear and bound by regional energy matrices; under deeply decarbonized grids, this technological displacement can theoretically yield an upper-bound 72% emissions reduction, whereas fossil-heavy power supplies significantly diminish net mitigation margins. Practically, this research provides an operational roadmap for shipowners and regulators navigating the Hong Kong Convention and carbon border mechanisms. This work concludes that sustainable shipbreaking has the potential to function as an economically viable, strategic reservoir of low-carbon raw materials essential for achieving international net-zero targets throughout the entire shipping structural lifecycle. Full article

Repeated-impact tests were carried out on a typical stiffened panel using both a wedge-shaped ice indenter and, for comparison, a rigid steel indenter under identical conditions. The tests were performed on a drop-weight impact system under a mass-loaded configuration, and the impact force, deformation response, and failure characteristics were recorded. Numerical simulations were additionally conducted to analyze the structural response and damage evolution. Progressive permanent deformation was observed under both impact types, whereas ice impact produced stronger fluctuations and a more scattered peak-force history. The differences between the two impact modes are clarified, providing a reference for the impact-resistant design and safety assessment of ships designed for ice-covered water. Full article

The crashworthiness of stiffened hull plates is essential for improving ship safety under collision and grounding loads. In this study, the impact resistance and energy-absorption mechanism of a U-shaped stiffened hull plate subjected to a wedge-shaped impact are investigated through drop-weight tests, nonlinear finite-element simulations, and analytical derivations. The experimental results show that the specimen experiences local indentation of the face plate, folding of the U-shaped stiffener webs, and crack propagation along the stiffener direction. The maximum residual deformation reaches 112 mm, and the failure mode is governed by the combined effect of face-plate stretching, web folding, and tearing near the contact or welded region. A finite-element model is established in ABAQUS and validated against the experimental deformation mode and force–indentation response. Furthermore, an analytical model based on the plastic upper-bound theorem is proposed to predict the instantaneous structural resistance. The total resistance is decomposed into contributions from the face plate, inclined webs, cap plate, and the tearing correction term. The analytical prediction agrees reasonably with the experimental and numerical results, with a peak collision force of approximately 620 kN at an indentation depth of about 124.5 mm. The proposed method provides a practical reference for rapid resistance prediction and crashworthy design of U-shaped stiffened hull plates. Full article

This article examines maritime piracy as a non-traditional security threat to global energy supply chains, focusing on its impact on the stability and resilience of maritime energy transport. As a significant share of oil and liquefied natural gas is shipped through vulnerable sea routes, piracy poses risks that extend beyond regional crime to global economic and geopolitical consequences. Using a comparative case study methodology based on secondary data from the ICC International Maritime Bureau, IMO GISIS, and ReCAAP, the study analyzes four key regions—the Somali coast, the Gulf of Guinea, the Red Sea corridor, and the Strait of Malacca—representing distinct piracy threat profiles, and examines their effects on critical energy chokepoints and the resulting economic and strategic disruptions. Through selected case studies and a review of current mitigation strategies, the paper highlights the need for coordinated international efforts to protect maritime energy security. Full article