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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Simulation-based investigation of ship response patterns in bi-chromatic following seas in support of model tests</title>
      <link>https://trid.trb.org/View/2607065</link>
      <description><![CDATA[The aim of this qualitative study was to numerically investigate surging and surf-riding in bi-chromatic following waves in order to facilitate a model test. The demand to evaluate the robustness of the existing theory was identified as a research gap. The focus of this study is the ship’s instantaneous surge velocity under bi-chromatic following wave conditions, which is referred to herein as the ship’s response. The study, carried out in a bi-chromatic wave, reveals new phenomena in ship’s response that cannot be found in the monochromatic wave conditions and shows the qualitative difference between regular and irregular waves. Characteristic response patterns have been observed and classified with the intention to be investigated in the experimental study on the towing tank in the nearest future. The results obtained, represent progress toward a deeper understanding of the surf-riding phenomenon in bi-chromatic following waves. Future work will include developing the simple single-degree-of-freedom mathematical model used in this study. It will be based on the comparison of the results of towing tank experiment and the numerical study.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2607065</guid>
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    <item>
      <title>Insights into the dynamics of cumulative broaching in regular stern-quartering waves</title>
      <link>https://trid.trb.org/View/2649733</link>
      <description><![CDATA[The paper discusses the dynamic instability that is known as cumulative broaching. This is a mechanism of yaw instability of ships in following/quartering seas where a significant deviation from the intended course occurs without observing any precedent surf-riding phenomenon. It is believed that cumulative broaching can occur irrespectively of a vessel's size and for speeds that are not particularly close to the celerity of the encountered wave. Earlier research, based on the linear horizontal-plane ship motion theory, has established that cumulative broaching is triggered by parametric yaw instability. For predicting the inception of parametric yaw, a simple analytical criterion was proposed, and steps were taken towards its validation. In the present study, a nonlinear ship maneuvering model is employed to investigate the dynamics of cumulative broaching, with focus on understanding how the build-up of parametric yaw can lead to the dynamic jump phenomenon associated with broaching. Then, the effect of different environmental or ship parameters towards avoiding such behavior could be assessed. The main investigative tool is a numerical continuation algorithm, effectively combined with the nonlinear surge–sway–yaw ship motions model for regular stern quartering waves.]]></description>
      <pubDate>Fri, 03 Apr 2026 12:12:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2649733</guid>
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    <item>
      <title>Hybrid modeling and online prediction of 4-DOF ship maneuvering motion in disturbed waters</title>
      <link>https://trid.trb.org/View/2594975</link>
      <description><![CDATA[This study aims to address the challenge of obtaining accurate and effective identification models online to predict four-degree-of-freedom (4-DOF) ship maneuvering motion in complex and dynamic maritime environments. Traditional offline modeling methods often rely on static datasets and fail to adapt to the continuously changing environmental and operational conditions encountered during actual navigation, resulting in limited prediction accuracy and robustness. To overcome these limitations, a hybrid modeling and online update (HMOU) framework based on data-driven is proposed to achieve dynamic prediction of ship motion states. Within this framework, an online modeling method is developed by integrating the enhanced proximal policy optimization (E-PPO) with the long short-term memory (LSTM) neural network to improve both accuracy and efficiency. Specifically, the standard PPO algorithm is enhanced with four enhancement components to strengthen the agent's ability to learn ship dynamics from limited data, and a lightweight LSTM structure is designed to reduce computational complexity. Based on training datasets collected in calm waters and disturbed waters characterized by wave effects and sensor measurement noise, nonparametric benchmark models for each response variable are first constructed using E-PPO through offline modeling. Subsequently, the uncertainty model is dynamically built by applying a sliding window and an online update mechanism to capture unknown dynamics and benchmark model errors. Finally, the HMOU model formed the offline E-PPO benchmark and online LSTM-based uncertainty models achieve the long-term online prediction of ship maneuvering motion. Taking the SR-108 container ship as the case study, simulation experiments including standard zigzag and turning circle maneuvers are carried out in calm and disturbed waters. The effectiveness of the algorithm improvements is verified in comparative experiments and ablation studies, and the advantages of the E-PPO method are emphasized by comparing the performance in different conditions. Experimental results on turning circle data and zigzag long-term series data with multi-maneuvers demonstrate that, compared to the offline E-PPO benchmark models, the optimal HMOU model reduces the root mean square error (RMSE) by 18.7 % and 25.2 % in turning circle and zigzag tests, respectively, which validates that it has better predictive accuracy and adaptability in the dynamic environment.]]></description>
      <pubDate>Wed, 24 Sep 2025 15:31:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2594975</guid>
    </item>
    <item>
      <title>Experimental exploration of surf-riding in bi-chromatic following waves – results for the 1/64 scale ship model</title>
      <link>https://trid.trb.org/View/2594459</link>
      <description><![CDATA[Surf-riding is a dynamic phenomenon leading to broaching-to that may result in a collision or lead to a large angle of heel, possibly even capsizing. While the phenomenon of surf-riding in regular waves is well understood, the same cannot be said fully for irregular waves. This research conducted at Gdańsk University of Technology explores the phenomena that are intended to replicate cases presented in recent theoretical works. The paper includes a comparison of calculations and experimental results carried out mainly in a qualitative manner, though with an attempt to compare them quantitatively as well. First, the experiments run in a 40 m towing tank using a 1/64 scale ITTC A2 purse-seiner have confirmed the feasibility of reproducing surf-riding in monochromatic waves, even in such a short tank. Furthermore, the results obtained in this study for bi-chromatic following waves constitute the first experimental confirmation of a number of characteristic phenomena for the considered two-component irregular wave that contribute to the broader concept of surf-riding in irregular waves.]]></description>
      <pubDate>Wed, 24 Sep 2025 15:31:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2594459</guid>
    </item>
    <item>
      <title>Measuring noise from ships underway : final report of the SHIPNOISE project</title>
      <link>https://trid.trb.org/View/2598654</link>
      <description><![CDATA[In the project SHIPNOISE we have developed a measurement station for both airborne and underwater noise from ships underway. The airborne noise levels indicate that there is a risk to exceed recommended indoor low-frequency noiselimits for dwellings positioned up to several hundred meters from the passing ships, although the effect on public health is uncertain. The underwater noise recorded at the SHIPNOISE measurement locations is strong enough to have an environmental impact on harbour porpoises, fish and also to some extent on invertebrates. During ship passages, thresholds for several different effects are exceeded. Harbour porpoises, herring and salmon are likely to avoid or escape the area when a loud ship passes. These effects are far more common at Böttö than at Lurö. Cod reproduction is also likely to be affected, again more at Böttö than at Lurö. The noisiest ships may even cause temporary hearing damage to porpoises at Böttö.]]></description>
      <pubDate>Fri, 12 Sep 2025 10:19:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598654</guid>
    </item>
    <item>
      <title>Numerical investigation of scale effects on cavitation and underwater radiated noise</title>
      <link>https://trid.trb.org/View/2598651</link>
      <description><![CDATA[Recent research efforts to reduce shipping noise emissions have been motivated by the growing awareness of its adverse effect on marine life. At this moment, there is a need for reliable noise assessment methods to support in designing more silent vessels. While sea trial measurements and model scale tests provide valuable data, they cannot be used during the early stages of ship design. Numerical methods, on the other hand, offer the tools for the assessment of noise emissions during these early stages. However, there is currently no well-established, consistent, and reliable approach for the prediction methods. In addition, the lack of research on scale effects on cavitation limits the ability to make informed design decisions. In this research work, the objectives focus on the assessment of scale effects on cavitation and the development of reliable tools for predicting underwater radiated noise from ships. Studied cases include a cavitating hydrofoil and a propeller operating in-behind condition. Results show that scale effects are more significant for the propeller case due to the interaction with the wakefield. At full scale, cavitation is less pronounced, which leads to significant differences in both pressure pulse levels and underwater radiated noise. In addition to scale effects, the impact of the domain/tunnel size on cavitation is investigated. Results indicate that blockage influences the wakefield upstream of the propeller, leading to less cavitation when using a larger computational domain. For the noise assessment, it is demonstrated that using the Ffowcs Williams-Hawkings acoustic analogy for hydroacoustic applications can produce inconsistent results. An alternative noise prediction methodology is proposed which models cavitation as a monopole source. Results are compared with sea trial measurements and model scale tests. While good agreement is obtained for pressure pulses, discrepancies occur for the noise level predictions. At low frequencies, sea trial measurements are dominated by engine noise, a source not accounted for in the numerical predictions. Better agreement is obtained when compared with model tests, but the numerical predictions still significantly underpredict the broadband noise levels. The results highlight challenges in obtaining reliable noise predictions and the need for more research in this area.]]></description>
      <pubDate>Fri, 12 Sep 2025 10:19:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598651</guid>
    </item>
    <item>
      <title>Comparative Analysis of the Dominant Models of Coastal Guard Structures in Europe with Access to Semi-Enclosed Seas</title>
      <link>https://trid.trb.org/View/2563720</link>
      <description><![CDATA[The paper presents different models of the organizational functioning of the coast guards of European countries with access to semi-enclosed seas. The subject of research is the Coast Guards of the Republic of Italy, the Hellenic Republic of, and the Kingdom of Norway with respect to different functional organizational models. Similarities and differences have been analyzed in terms of their organizations, capacities, roles in ensuring maritime security, and protecting the sovereignty of their countries. Special attention is paid to the organizational structure and operations of the Coast Guard of the Republic of Croatia. The paper also explores and analyses the management model of the Coast Guard of the Republic of Croatia in the context of operational efficiency in protecting rights and interests in the maritime areas of the research geographical region, the semi-enclosed Adriatic Sea – eastern part. A comparative analysis of the considered coast guards is presented.]]></description>
      <pubDate>Tue, 17 Jun 2025 09:42:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2563720</guid>
    </item>
    <item>
      <title>Maritime spaces as a strategic environment for the climate security of the European Union</title>
      <link>https://trid.trb.org/View/2528617</link>
      <description><![CDATA[Today, environmental degradation, understood as the loss of biodiversity and pollution attributed to climate change, has increased vulnerability and exposure to peace and security risks in coastal zones and maritime spaces. Extreme weather events, rising sea levels and loss of marine resources are factors that act as catalysts for instability and insecurity in the global maritime domain by fuelling transnational crime, piracy, maritime boundary disputes and geopolitical fragility because of access to natural resources on the ocean floor. Against this backdrop, in order to safeguard security interests and ensure ocean governance in each of its sea basins and outermost regions, the European Union addresses climate change and environmental degradation as a threat to maritime security by linking each of the priority objectives defined in the revised Maritime Security Strategy (2023) to their protection in the interests of so-called climate security. This paper addresses the consideration of climate change as a non-traditional threat to maritime security, the main lines of action envisaged by the European Union to counteract it and the mechanisms and initiatives planned to promote peace, security, and freedom of navigation. To this end, the authors will analyse the official documents and the scientific-academic narrative linking climate change and maritime security, as well as those reflecting the official position of the European Union in this field, in order to identify possible gaps and future lines of action to be taken by the actors involved.]]></description>
      <pubDate>Tue, 20 May 2025 11:37:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2528617</guid>
    </item>
    <item>
      <title>Eko Marina III - inventory, mapping and environmental support for Sweden's recreational marinas inventory of Sweden's recreational marinas, mapping of their structure, and the development of a prototype for a self-monitoring system for environmental sustainability</title>
      <link>https://trid.trb.org/View/2534290</link>
      <description><![CDATA[Eko Marina III is the third part of a project which began in October 2019, with the overarching aim of exploring the possibilities for developing eco-labelling for Swedish marinas that could decrease their negative environmental impact. This part of the project has focused on three primary tasks: 1. To produce an extensive inventory of Sweden's recreational marinas, 2. To map the marinas' structures, with the aim of better understanding their functions, opportunities and limitations, and 3. To begin the development of a digital tool which can include an eco-label index whilst also comprising a support platform for marinas in their work towards sustainable conversion.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:16:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534290</guid>
    </item>
    <item>
      <title>The impact of wind farms on winter navigation</title>
      <link>https://trid.trb.org/View/2534258</link>
      <description><![CDATA[In 2022, the Swedish Government adopted the first Swedish marine spatial plans. At the same time, The Swedish Agency for Marine and Water Management (SwAM) was assigned to bring forth proposals for amended marine spatial plans to meet the need for increased electricity production. These plans include and identify several areas in the Gulf of Bothnia that may be suitable for offshore wind power installations in the form of dense wind farms. These farms are planned geographically based on several parameters, including minimizing the impact on commercial shipping in the area, which follows predictable routes during the summer. The Gulf of Bothnia, especially the Bay of Bothnia, is completely or partially covered with ice of varying thickness and concentration during the winter. The ships that operate in these areas during winter therefore require the assistance of icebreakers. Requirements for economic and environmental sustainability are the basis for effective icebreaker planning where, due to the dynamics of the ice, the routes vary greatly from week to week. Offshore wind power hinders and blocks the choice of ship routes and also risks affecting ice formation and the nature of the ice. The project has carried out a literature study to compile current knowledge about ice formation in the vicinity of offshore wind farms. It shows that there is a large knowledge gap in the area. There is therefore a great need for further research to understand if and how the ice formation at wind farms develops to ensure safe installations and how the ice formation may affect, for example, winter navigation. The project has developed a generally applicable methodology for assessing how shipping is directly affected by offshore wind farms both in summer and winter by limiting the range of available shipping routes.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:15:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534258</guid>
    </item>
    <item>
      <title>Holistic assessment of ship scrubbers, with emphasis on the marine environment</title>
      <link>https://trid.trb.org/View/2534201</link>
      <description><![CDATA[The ocean is essential, providing life support, food and recreation and ocean economy is projected to grow, implying more human activities and ocean claims. A key player in ocean economy is the shipping sector, both as an industry on its own and as a prerequisite for the development of other ocean-based sectors. The daily operations of a ship exert multiple pressures on the environment, affecting climate change, human welfare and ocean health. As shipping can trigger change in environmental state which may cause negative impact on both the environment and human welfare, there is a need to get a complete perspective of the environmental impacts associated to ship activities. The DAPSIR framework offers a structured approach to assess the cause-effect relationship of society (Drivers, Pressures), environment and human welfare (State, Impact) and policy (Response). The overall aim of this thesis is to assess pressures, changes in environmental state and impacts on the marine environment following the wide-scale use of scrubbers, an aftertreatment technology to reduce sulphur oxide emissions to the atmosphere by spraying the exhaust with (sea)water, producing large volumes of heavily acidified and contaminated water that is discharged to the marine environment.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:14:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534201</guid>
    </item>
    <item>
      <title>Methods for bathymetry informed planning of archipelago transport systems</title>
      <link>https://trid.trb.org/View/2491286</link>
      <description><![CDATA[Archipelagos are rural regions characterized by their distinct geographic layouts with many separated island communities. Water bodies hinder access to community services and make a well-functioning ferry-based public transport system the only feasible means of mass transportation. Both between islands and to connect to the mainland. Maritime environments provide great routing flexibility. However, outdated or imprecise nautical charts can hinder the safe use of such possibilities in commercial traffic. This thesis develops methods for strategic planning of archipelago transportation systems, enabling the valuation of novel fairways. Contributions are made to the fields of applied optimization and statistical modeling of spatial data considering the distinct features of archipelago environments.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:17:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491286</guid>
    </item>
    <item>
      <title>Ship noise in coastal regions : Final report of the SHIPNOISE project</title>
      <link>https://trid.trb.org/View/2491210</link>
      <description><![CDATA[Ships carry cargo and passengers around our planet. In coastal regions, complaints about ship noise have been raised from nearby residents. Ships are also the dominant source of continuous underwater noise in the seas. In the SHIPNOISE project, we investigate levels of ship noise in coastal regions using a custom measurement station for both airborne and underwater noise from ships underway. The measurement station is developed using embedded microprocessors for low power consumption. The station is deployed at Böttö at the inlet to Gothenburg harbor, and then at Lurö in Lake Vänern. These sites are close to shipping lanes of different traffic intensity.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:16:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491210</guid>
    </item>
    <item>
      <title>SHIPCOST - Samhällsekonomisk analys av sjöfartens samlade belastning på havsmiljön</title>
      <link>https://trid.trb.org/View/2440081</link>
      <description><![CDATA[International shipping is important for the world economy and the IMO has estimated that about 90% of all goods in world trade go through shipping. However, shipping emits various types of air pollutants that affect both human health and contribute to climate change, eutrophication, and acidification of both land and water. In addition, shipping has a negative impact on the marine environment through the spread of alien species, microplastics and through emissions of hazardous substances from, for example, antifouling paints, bilge water, wastewater from toilets, baths, dishes and laundry (Jalkanen et al. 2021). Today, there are certain tools that can be used to calculate the societal cost of emissions that affect climate and human health, and these tools are used by urban planners, decision-makers and other stakeholders for the design and analysis of policy instruments. However, in order to design effective policy instruments, it is important that decision-makers have a comprehensive basis for how emissions can also affect the marine environment, something that is often lacking in analyses both at national level (Transport Analysis), regional (sea conventions HELCOM, OSPAR) and at international level (EU, IMO).]]></description>
      <pubDate>Thu, 10 Oct 2024 14:38:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2440081</guid>
    </item>
    <item>
      <title>The influence of waves and hydrodynamic interaction on energy-based evaluation of ice loads during a glancing impact in sea states</title>
      <link>https://trid.trb.org/View/2404518</link>
      <description><![CDATA[This research investigates the effect of waves and hydrodynamic interaction on the ice loads during a glancing impact between an ice floe and a ship advancing at low speed in various sea states. An extended energy-based model is proposed for the ice loads estimation, accounting for hydrodynamic interaction through added mass and wave-induced motions, where the hydrodynamic interaction is fully involved between an advancing ship and a free-floating ice floe. The influence of sea states is investigated by calculating the added mass and motions of a ship and ice floes in six degrees of freedom under different significant wave heights and peak periods. The effect of ice floe size is analyzed by using three ice floes with different diameters. The results reveal that sea waves significantly affect ice loads by altering the relative velocity between the ship and the ice floe right before the impact. Furthermore, the influence of added mass on ice load predictions is not as pronounced as the effect of wave-induced motions. This research underscores the importance of considering hydrodynamic interactions and wave conditions in the accurate assessment of ice loads, which is crucial for the design of ice-strengthened ships and for the selection of safe speed according to sea state in ice-infested waters.]]></description>
      <pubDate>Thu, 03 Oct 2024 09:37:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2404518</guid>
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