This chapter is a historical case study of Maersk Line, the world’s leading container carrier. Maersk Line’s global leadership was achieved within a relatively short time period and was the result of Mærsk Mc-Kinney Møllers decision in 1973 to enter container shipping—the biggest investment in the history of the AP Moller companies. When Maersk Line managed to achieve global leadership in a period of just about 25 years, the company’s own country offices were particularly important. They allowed the interconnection of three types of networks: The physical network of ships and routes, the digital network of information and communication systems and the human network of Maersk employees. The interaction between the vessels, the systems and the people is still at the core of the company today and central to its continued development.
This PhD thesis presents a numerical solution of the hydroelastic problems encountered especially by large flexible ships sailing in waves. The solution is implemented by extending an existing seakeeping tool (OceanWave3D-seakeeping) to allow for the efficient and accurate evaluation of the hydroelastic response of ships. OceanWave3D-seakeeping has been developed by the Maritime Group at DTU-Construct based on solving the linearized potential flow theory using high-order finite differences on overlapping curvilinear boundary-fitted grids. Modal superposition is employed to couple the hydrodynamic and structural analysis of ships at both zero and non-zero forward speed. The ship girder is approximated by an Euler-Bernoulli or a Timoshenko beam, and the vertical bending deformation is mainly considered in this work. The shear effects on the hydroelastic response are also investigated in the Timoshenko beam approximation. The solution has been validated against experimental measurements and reference numerical solutions for several test cases. The correct computation of the hydrostatic stiffness, structural stiffness and hydrodynamic forces is the key to the
accurate prediction of the hydroelastic response, and these three terms are discussed deeply in this thesis.
With respect to the hydrostatic stiffness model, some controversy has long existed in the literature about its correct form for elastic motion modes, with Newman [1] and Malenica [2] arriving at different forms which are respectively defined in earthand body-fixed reference systems. In this thesis a complete derivation of both forms including the buoyancy and gravitational terms is provided, and the equivalence of the two models associated with elastic motions is confirmed.
A finite element method (FEM) is a common way to compute the structural stiffness of ship hulls. However, for large modern ships, a FEM calculation based on a full structure is inevitably time-consuming since distinguished differences between the longitudinal and the cross-sectional scales of ship hulls usually exist, and the sectional configurations are generally complex, bringing difficulties to numerical modeling. Considering that the structure of modern ships (for example container ships), is usually nearly periodic in the longitudinal direction, in this thesis the ship hull is approximated as a periodic beam and a new implementation of asymptotic homogenization (NIAH) is introduced to efficiently calculate the structural stiffness. This can greatly improve the computational efficiency compared with a full FEM model. Several test cases with both solid and thin-walled sections are given to validate the proposed technique. A range of representative mid-ship sections for a container ship are also considered to investigate the influence of stiffeners on the hydroelastic response.
In the hydrodynamic part, zero-speed and forward-speed radiation and diffraction problems including the well-known m−terms in the body boundary conditions, have both been solved. For generalized modes, the boundary conditions using the corresponding generalized m−terms are applied in the calculation. Neumann-Kelvin (NK) and double-body (DB) linearization models are applied as the steady base flow, and their performance is investigated by comparison with experimental measurements. In head seas, the influence of increasing forward speed on the resonant response of the flexible modes is also studied.
Through the integration of hydroelastic analysis using potential flow theory, and advanced numerical techniques, this thesis contributes to a deeper understanding of the complex interaction between flexible ship hulls and ocean waves, offering valuable insights for the maritime industry.
This report provides public recommendations for waterborne transport to West Coast of Norway, with the focus on the specified transport system in use case A in the AEGIS project. The complete background for this report is only achieved by reading all the other deliverables related to the use case, however these are confidential. Therefore, it is recommended to read the ICMASS 2022 paper "Development of an advanced, efficient and green intermodal system with autonomous inland and short sea shipping – AEGIS"1 to get a better overview of the project and specifically use case A. The transport system of use case A consists of mother vessel(s) together with one or more daughter vessels, connected by several ports. The mother vessel transports containers from Rotterdam via Hitra Kysthavn and into ports in the Trondheimsfjorden. The rationale for this use case is to enable a more flexible and cost-efficient waterborne transport solution for fjords and smaller ports.
This work presents a comparative study of two signal processing methods for the estimation of the roll natural frequency towards the real-time transverse stability monitoring of fishing vessels. The first method is based on sequential application of the Fast Fourier Transform (FFT); the second method combines the Empirical Mode Decomposition (EMD) and the Hilbert-Huang Transform (HHT). The performance of the two methods is analysed using roll motion data of a stern trawler. Simulated time series from a one degree-of-freedom nonlinear model, and experimental time series obtained from towing tank tests are utilized for the evaluation. In both cases, beam waves are considered but, while irregular waves are adopted in the simulated data, the towing tank tests are made in regular waves. Based on the available data the performance of both estimation methods is comparable, but the EMD-HHT method turns out slightly better than the sequential FFT. Finally, the use of a statistical change detector, together with the EMD-HHT methodology, is proposed as a possible approach for the practical implementation of an onboard stability monitoring system.
Containerfartens historiske udvikling bliver i litteraturen beskrevet som en revolution og en transformation af den internationale shippingbranche. De teknologiske og organisatoriske forandringer af livet til søs som fulgte med containerfarten har tilsvarende medført en forandring af maritime kulturer og en udfordring af de søfarendes identiteter.
Denne afhandling handler om danske containersøfolks erindringer, fortidsbrug og identitetskonstruktioner og undersøger, hvordan søfolkene fortæller sig selv i relation til deres levede erfaringer i containerfarten. Jeg analyserer i afhandlingen søfolkenes retrospektive fortidsfortolkninger som en måde at nærme mig en forståelse af de forandrede sømandsidentiteter.
Analytisk anlægger afhandlingen et subjektperspektiv, som anser fortiden for nærværende og åben i de mundtlige fortællingers fortolkninger og meningsforhandlinger af fortidens erfaringer. Jeg anskuer den narrative konstruktion af den personlige, autobiografiske, historie som identitetsdannende fortidsbrug, der udtrykker fortællerens subjektivitet. Med en erindringshistorisk tilgang til søfolkenes mundtlige fortællinger undersøger jeg, hvordan vi mennesker forstår os selv gennem de historier, vi fortæller om os selv.
Afhandlingen bygger empirisk på en række dybdegående oral history interviews med danske søfolk, der alle har erfaring inden for den internationale containerfart.
I afhandlingens analyser, viser jeg, hvordan søfolkene retfærdiggør og legitimerer deres valg om i første omgang at blive søfolk og senere at arbejde ombord på containerskibe. Jeg viser, hvordan søfolkene narrativt forhandler forskellige former for erfaret meningstab og aktivt tilskriver arbejdet og fællesskabet ombord på skibene en ny og brugbar mening. Jeg viser samtidig, hvordan den personlige historie konstrueres i dialog med kulturelt dominerende forestillinger og fortællinger. Sådanne forestillinger og fortællinger tilbyder den enkelte fortæller et tilgængeligt sprog at udtrykke sine personlige erfaringer i, men kan også virke begrænsende, hvis fortællerens erfaringer og forståelser ikke passer ind i de dominerende billeder. I sådanne tilfælde kan der opstå, hvad afhandlingen kalder en form for narrativt ubehag (discomposure), der kommer til udtryk som frustration og brud i fortællingens narrative sammenhæng.
Som en gennemgående metodisk pointe viser afhandlingen, hvordan interviewets intersubjektivitet er med til at forme den historie, som fortælles. Det personlige møde mellem fortæller og historiker og interviewets kulturelle kontekster indvirker på forskellig vis på den konstruerede historie. Fremfor at hævde en neutral og objektiv interviewsituation, tager afhandlingen i stedet konsekvensen af denne intersubjektivitet og skriver det konkrete møde mellem søfolkene som fortællere og mig som interviewer ind som en integreret del af den historiske fremstilling. Dette er både et narrativt greb og et metodisk valg, der skal sikre transparens ved at give læseren indblik i, hvordan historierne og mine tolkninger er blevet til.
Afhandlingen yder med sin tilgang og sine analyser flere bidrag til den eksisterende litteratur. Gennem de personlige fortællinger får vi større indsigt i søfolkenes levede liv og deres erfaringer med containerfartens historiske udvikling. Afhandlingen giver et menneskeligt perspektiv på historien om den internationale containerfart, der bidrager til vores viden om udviklingens identitetsmæssige betydning for de mænd og kvinder, som gennemlevede de historiske forandringer ude ombord på skibene.
Afhandlingen er en virksomhedshistorie, der tager oral history alvorligt både som forskningsfelt, metode og genre. Afhandlingen bidrager med sin erindringshistoriske tilgang til oral history til den fornyede samtale mellem forskningsfelterne oral history og virksomhedshistorie. Afhandlingen bringer metodiske og teoretiske indsigter fra den erindringshistoriske tradition ind i virksomhedshistorie og viser gennem sin egen narrative stil potentialet i en historieformidling, der sætter subjektivitet og erindring i centrum af sin analyse. Dermed bidrager afhandlingen også til den narrative vending inden for virksomhedshistorie ved ikke kun at anlægge et narrativt blik på de danske søfolks fortællinger men ved også at tage sig selv alvorligt som narrativ konstruktion.
Automated fish documentation processes are in the near future expected to play an essential role in sustainable fisheries management and for addressing challenges of overfishing. In this paper, we present a novel and publicly available dataset named AutoFish designed for fine-grained fish analysis. The dataset comprises 1,500 images of 454 specimens of visually similar fish placed in various constellations on a white conveyor belt and annotated with instance segmentation masks, IDs, and length measurements. The data was collected in a controlled environment using an RGB camera. The annotation procedure involved manual point annotations, initial segmentation masks proposed by the Segment Anything Model (SAM), and subsequent manual correction of the masks. We establish baseline instance segmentation results using two variations of the Mask2Former architecture, with the best performing model reaching an mAP of 89.15%. Additionally, we present two baseline length estimation methods, the best performing being a custom MobileNetV2-based regression model reaching an MAE of 0.62cm in images with no occlusion and 1.38cm in images with occlusion. Link to project page: https://vap.aau.dk/autofish/.
The purpose of this project is therefore to develop a software tool that can implement an automated intelligent registration (artificial intelligence) of the catch of cod on board the vessel. The project can both support the ongoing camera projects, but also functions as a forward-looking method where the concept of this approach is that the camera focuses on the catch and can be implemented without human supervision. This has a number of potential advantages, including that human supervision is avoided, the number of cameras can probably be reduced to just one (although possibly a stereo camera), labor resources are saved by automated monitoring, it will be possible to reduce the amount of data, fishermen can target selective fishing based on the information obtained, increased precision in relation to possible legal
use of the observations and overall it will reduce costs. The project supports the monitoring that has been initiated in the Kattegat, but should also be seen as a future development, including internationally, where the focus is on building monitoring/surveillance around the use of images as documentation of the catch. An extremely important element of the project is to create a high-quality dataset that can be used internationally to improve algorithms and intensify research.
Given the move toward automation, an increased focus on the liability for technical defects must be anticipated. This brings into play liability regimes that have traditionally been less used in the maritime area. One of these liability regimes is product liability. It is the purpose of this contribution to examine the implications of product liability rules in the maritime area, seen in light of the automation of ships.
This PhD theis focuses on identifying the opportunities and challenges that on-board maintenance and practical operation of vessels poses in the development of autonomous ships. Inspired by the rapid development of autonomous vehicles considerable effort and interest is now invested in the development of autonomous ships. So far however, most of the research has focused on the legal aspect of unmanned vessels and on developing a system enabling a vessel to operate within the maritime collision regulation without human interaction. Specifically, the theisi looks into three research questions: (1) How is autonomous technology going to affect the workload required for operating and maintaining modern cargo vessels? (2) How is autonomous technology going to affect the operational patterns of the vessels? And (3) How is autonomous technology going to affect the reliability and utilization rate of the vessels?
The study is planned in cooperation between Svendborg International Maritime Academy (SIMAC) and University of Southern Denmark.