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 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.
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.
Green House Gas (GHG) emissions are not the only emissions of concern to the international transport community. SOx emissions are non-GHG emissions that are caused by the presence of sulphur in the fuel. As the maximum percentage of sulphur in automotive and aviation fuels is strictly regulated in most countries around the world, much of the attention in recent years has focused on maritime transport. The attention mainly stems from the fact that in marine fuels the percentage of sulphur can be very high: it can be as high as 4.5 % in Heavy Fuel Oil (HFO), which is the fuel typically used in all deep-sea trades. Even though the amounts of SOx produced by ships are substantially lower than CO2, SOx emissions are highly undesirable as they cause acid rain and undesirable health effects in humans and animals. To mitigate these adverse environmental effects, the international shipping community has taken substantial policy measures. With the introduction of new limits for the content of sulphur in marine fuels in Northern European and North American sea areas, short-sea companies operating in these areas will face substantial additional cost. As of 1/1/2015, international regulations stipulate, among other things, a 0.1%limit in the sulphur content of marine fuels, or equivalent measures limiting the percent of SOx emissions to the same amount. As low-sulphur fuel is substantially more expensive than HFO, there is little or no room within these companies current margins to absorb such additional cost, and thus significant price increases must be expected. Unlike its deep-sea counterpart, in short-sea shipping such a freight rate increase may induce shippers to use landbased alternatives (mainly road). A reverse shift of cargo would go against the EU policy to shift traffic from land to sea to reduce congestion, and might ultimately (under certain circumstances) increase the overall level of CO2 emissions along the entire supply chain. The purpose of this chapter is to investigate the potential effect of sulphur regulations on the share of cargo transported by the waterborne mode vis-à-vis land-based alternatives.
Capacitors are fundamental electronic passive components and there are nearly everywhere. There are many different capacitors technologies, with different dielectric materials, form factors and terminals and housings available. This short encyclopedic article discuss the main capacitor types which are relevant for power electronic applications. The main types are Aluminum Electrolytic Capacitors, Metallized Film Capacitor, Ceramic Capacitors and Supercapacitors. The principal construction, materials and properties and technological limitations are discussed. Further new upcoming trends of new materials and designs are presented.
What is the role of the sea in globalized capitalism? In their new book Capitalism and the Sea: The Maritime Factor in the Making of the Modern World, Liam Campling and Alejandro Colás explore this question through a historical and geographical lens. In this book, the authors track the larger history of maritime commerce and pursue new understandings of the role of the sea in the global economy. In doing so, they illuminate the understudied maritime spaces, systems, and flows that underpin the global economy and create the foundations of global material circulation.
The safety of people and cargo onboard is a key functionality of a commercial ship.
The health and well-being of seafarers and passengers is protected through an extensive set of technical specifications, standards and norms that govern the design and commissioning of all vessels.
They differ by ship type and size, while the specific services to be provided and the specific geographic regions to be served also play an important role in this respect.
The requirements are of national and international character and vary also with the classification society that will commission the ship. Thus in a broader sense, all competences related to ship design are related one way or another to maritime health.
Much of the design of ships is overseen by a naval architect or marine engineer. It is rare to have the involvement of a medical professional except in the cruise industry.
Purpose and tasks
To ensure that the design of a ship includes the requirements to protect the health and well being of seafarers. More specifically, to identify areas of intervention that go beyond the usual engineering curricula where, nonetheless, the safety dimension is embedded through international standardization.