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.
The DNV Nordic Maritime Universities Workshop is organized as a collaboration between DNV and universities in the Nordic region with a maritime related education or research line. The workshop covers all research topics related to naval architecture, maritime engineering and maritime transport, including safety, energy efficiency and environmental performance, environmental pressures, new technologies and digitalization. The 25th Nordic Maritime Universities Workshop was held on 30-31 January 2025 at the Technical University of Denmark (DTU), Lyngby Campus. The workshop has been organized and hosted by the Maritime Group at the Department of Civil and Mechanical Engineering (DTU Construct). In total we received 77 abstracts from 7 countries. This includes 23 abstracts from Denmark, 23 from Sweden, 16 from Norway, 10 from Germany, 3 from Finland, 1 from The Netherlands, and 1 from Poland. The presentation of the abstracts and the talks is carried out over two days of the workshop and in 10 sessions, distributed over 7 topics:
• Maritime Safety & Risk Reduction (17 talks)
• Structures & Ship Design (8 talks)
• Numerical Methods & Marine Hydrodynamics (14 talks)
• Ship Operations & Navigation (14 talks)
• Autonomous Shipping & Digitalization (8 talks)
• Alternative Marine Fuels (8 talks)
• Wind Assisted & Alternative Propulsion (8 talks)
This year a special issue has been initiated in International Shipbuilding Progress to commemorate the 25th Nordic Maritime Universities Workshop. All abstract presenters have been invited to submit a full paper, to be considered for publication in this journal after a peer-review process. This compendium includes the workshop program, the session details and the 77 abstracts arranged in alphabetical order.
This is an informational document that communicates the account of SDU participants of the MISSION project on how to prove whether the system being developed by the consortium improves the safety of ships in the port areas.
The methods suggested in this document are based on an overview of the state-of-practice guidelines and state-of-the-art methods in safety risk analysis. They are compliant with the Guidelines for Formal Safety Assessment (FSA) and The Ship Inspection Report Programme (SIRE).
Other accounts on the same issues may exist that are either complementary or preferred over the methods described in this paper. This document is intended to make discussions constructive by possibly benchmarking other views with those described here and by working out a clear methodology and guidelines for conducting a safety risk analysis of the system being developed; and for informing decisions on the system’s acceptability or improvements needed to achieve the acceptability.
OBJECTIVES: Cardiovascular disease (CVD) is the leading cause of death globally and the second most frequent cause of death in Denmark. Due to their unique occupational environment, seafarers are exposed to numerous risk factors for CVD including lifestyle and work-related factors. This study aims to investigate CVD mortality among Danish seafarers by comparing them to the economically active reference population.
METHODS: This register-based cohort study included data on all Danish seafarers from 1993 to 2016 and compared them with the economically active Danish population not working as seafarers. The seafarers' mortality was calculated using piecewise stratified Cox regression adjusting for potential confounders. Mortality was further analyzed by diagnosis groups, vessel type and employment duration.
RESULTS: Among 52 861 seafarers, 4226 deaths were observed, with 866 (20.5%) of these attributed to CVD. Male seafarers had higher all-cause mortality in age groups 18-44 years (HR 1.46, 95% CI 1.33 to 1.62), 45-64 years (HR 1.43, 95% CI 1.37 to 1.50) and 65+ years (HR 1.32, 95% CI 1.26 to 1.39) compared with the reference population. CVD mortality was increased for male seafarers aged 45-64 years (HR 1.27, 95% CI 1.13 to 1.42) and 65+ years (HR 1.34, 95% CI 1.21 to 1.48). The mortality was higher for male seafarers for ischemic heart diseases, other forms of heart diseases, cerebrovascular diseases and diseases of arteries, arterioles and capillaries. CVD mortality was also observed based on vessel type.
CONCLUSIONS: The study provides evidence of elevated CVD mortality among Danish seafarers. Future research should focus on identifying effective strategies to improve the cardiovascular health of seafarers.
Current practice for maritime search and rescue (MSAR) adheres to predetermined full-coverage patterns for finding targets. These do not account for key success factors for MSAR missions such as the dynamic location of targets, updates on situational awareness during mission execution, and search vehicle kinematics. Consequently, current practice cannot incorporate realistic MSAR operational conditions into path-finding, increasing the likelihood of mission failure. To address this issue, a novel, flexible path-finding framework is proposed for generating a path while dynamically updating the probability of a target based on the path's trajectories. The solution approach implements the A* algorithm, which can accommodate the dynamics of a vehicle and guarantees the optimality of the final path with respect to the target objective function. Experiments show that a more than 50% improvement in the time needed to guarantee a certain probability of finding a target is exhibited compared to the parallel sweep coverage path-finding approach.
A serious ship-bridge collision accident happens about once a year. These accidents cause fatalities and large economic losses due to loss of transportation service and replacement cost of the bridge structure. One of the most recent, widely published, ship-bridge collisions was the collision where the containership Dali in 2024 collided with the Baltimore Key Bridge in the US city of Baltimore. The resulting collapse of the bridge girder caused six fatalities as well as large financial losses. One effect of this event has been that engineers around the world now are being engaged in evaluation of the vulnerability of existing bridges and establishment of rational design criteria for new bridges.
The presentation will outline elements of a rational design procedure for bridge structures against ship collision impacts. A set of risk acceptance criteria will be proposed and a mathematically based procedure for calculation of the probability of ship collision accidents caused by human as well as technical errors will be presented. This first part of the presentation leads to identification of the largest striking ship, “design vessel”, a given bridge element must withstand without structural failure in order for the bridge connection to fulfil the risk acceptance criteria.
The final part of the presentation will be devoted to an analysis of the needed impact capacity for the bridge pylons and piers exposed to ship bow impact loads from design vessels. A procedure will be described for derivation of expressions for ship bow crushing forces, which can be used in design against ship collision impacts. The resulting collision force expressions are verified by comparison with large-scale laboratory experiments and an analysis of a fullscale shipping accident. Finally, the proposed impact force expressions will be compared with existing standards for modelling ship collisions against bridges as published by AASHTO, IABSE and Eurocode.
Background: Medical evacuations (MEDEVACs) from offshore installations are both costly and disruptive. Enhancing worker well-being may help reduce evacuations due to illness or injury, thereby maintaining the smooth operation of offshore activities and lowering financial burdens.
Objectives: This scoping review aims to identify whether illness or injury is the predominant cause of MEDEVACs from offshore oil and gas installations and to determine the most common types of illnesses or injuries involved. Additionally, the review outlines a future research agenda focusing on offshore worker health and well-being.
Materials and methods: A comprehensive structured search was conducted across the Scopus, PubMed, and Web of Science databases, as well as through reference lists and grey
literature. Studies were included if they addressed MEDEVACs from offshore oil and gas installations. Eleven articles met the inclusion criteria.
Results: Articles indicate that non-occupational illnesses are more frequent causes of MEDEVACs than injuries. Among these, chest pain, cardiovascular issues, and dental problems were disproportionately represented. Contractor personnel were more likely to require evacuation than company employees. Additionally, younger workers were more likely to be evacuated due to injuries. Chronic health conditions were more common reasons for MEDEVACs among older workers. The review highlights the significant role of non-communicable diseases in contributing to MEDEVACs, as opposed to occupational exposures.
Conclusions: Investing in preventive health management, targeted research, and workforce education may substantially reduce the prevalence of non-communicable diseases in the offshore environment, lowering MEDEVAC rates, associated costs, and operational disruptions. Further investigation into the underlying causes of ill health among offshore workers is needed to enhance overall workforce well-being.
Subsea power cables are crucial for transmitting electrical power between offshore installations, islands, and onshore infrastructure. The demand for these cables has surged with the expansion of offshore wind farms. Despite mechanisation, divers are still needed for tasks such as installation, inspection, and remedial work, facing hazards like entanglement, equipment damage, and those to the environment. Therefore, analyzing accidents in diving operations during subsea cable installation is essential to develop safety measures that protect divers and ensure successful installations. This document reports an analysis of the hazards and accident events linked to diving operations during subsea cable installation. Few risk assessments of these operations have been made publicly available.
Various methods can be used to analyze diving accidents, but this document reports on the use of the Accident Anatomy (AA) method. The AA method combines fault trees and cause-consequence diagrams to map accident causes and consequences. In the AA method, evidence-based (post-accident) analysis is used jointly with predictive analysis to identify deviations from normal conditions that could lead to accidents.
To exhaust the identification of hazards, the AA method is additionally powered by an error mode classification checklist, which classifies errors that produce similar effects on a system. Analysts used this checklist to identify hazards for each basic diving operation task identified.
As a data source, 163 documents were analyzed, including accident records, regulations, manuals, and scientific papers. Basic tasks associated with diving operations are identified, along with hazards for each task. Predictive analysis identifies potential events and unwanted consequences when normal conditions (specified in safety procedures and specifications) deviate. The unwanted consequences that were found include delays, technical problems, injuries, and fatalities. Ultimately, safety measures are identified for each basic task to reduce the effects of hazards.
Background
The transfer of offshore wind farm workers between transport vessels and wind turbines is a hazardous operation with a disproportionately high occurrence of "high potential" incidents. Motion sickness has been reported to affect offshore wind farm worker well-being, and has been identified as a job demand, especially during crew transfer and ladder-climbing operations.
This scoping review sought to determine the extent to which current research defines, describes, and quantifies MS among offshore wind farm workers and to identify relevant research gaps.
Methods
Using terms related to motion sickness and offshore wind farm operations, searches were conducted of the PubMed, Scopus, and Web of Science databases. Studies published in English between 1990 and 2024 were included.
Results
795 articles were retrieved, of which 11 articles met the inclusion criteria. The included articles describe MS as a job demand but do not clearly define it in the research context. Consequently, it remains unclear which symptoms of MS constitute a job demand and how workers are affected. Additionally, indications of motion sickness prevalence are required, using a clear definition which accounts for the wide range of subjective symptoms other than vomiting.
No research appears to have been carried out where motion sickness among wind farm workers has been studied as a broad occupational health issue within the offshore wind energy sector.
Conclusions
This review identifies significant research gaps concerning motion sickness among offshore wind farm workers. Motion sickness-related issues have either been overlooked, studied in isolation, or insufficiently addressed. These issues constitute empirical, methodological, and knowledge gaps, necessitating a need for systematic studies that address these research gaps in the context of the offshore wind energy sector.
This study examines how the work of the International Law Commission (ILC) has contributed to the ‘progressive development’ of general international law relevant to regulating rescue and disembarkation of refugees and migrants found at sea. It explores the ILC’s texts on interpretation and implementation of international obligations, state responsibility, fragmentation and harmonization of international law, and the status of certain principles of general international law, including jus cogens general principles of law and the principle of good faith, which present legal parameters for regulation of maritime search and rescue operations. In conducting doctrinal examinations of international law and gathering evidence of the practice of States and other relevant actors, the ILC contributes by analysing, clarifying, and systemising important topics of general international law. However, state implementation frequently falls short of the legal interpretations of the ILC, particularly as they relate to respect for and protection of human rights at sea. Therefore, while the ILC needs new strategies to directly connect with States and international organisations, it remains reliant on the mutual following of national and international courts and tribunals, and its mutual contribution in scholarship.