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An advanced salvage method is proposed for damaged ships to ensure a short-term decision-making process for a safe ocean towage to the repair yard. The residual longitudinal strength must be greater than the sum of the still water and the maximum vertical wave bending moment. The ultimate bending moment is determined numerically for a container vessel by using an incremental iterative approach (Smith method) and wave-induced loads are predicted by means of hydrodynamic analyses. Successful applicability of the advanced salvage method is demonstrated for a damaged container vessel, which was towed from La Libertad, Ecuador, via Panama to the repair yard in Zhoushan, China, in restricted environmental conditions.

The restriction of tensor-product B-splines to regular control meshes and thus four-sided surfaces is the reason that hull form modeling is still a challenge. This limitation is addressed by subdivision surfaces as they originate from the idea to define B-spline surfaces on irregular control meshes. Often subdivision is considered as a method to refine polygon meshes, but the linear nature of polygon meshes is generally not qualified for hull form representation. Therefore an introduction to the theory of generalized B-splines is given which employs the notion of subdivision to define smooth B-spline surfaces on irregular control meshes. This article covers the application of generalized B-splines for the representation of hull forms. It is possible to represent hull forms with a single B-spline surface. The main advantage is, however, the ability to use the control mesh for modeling. It is shown that the structure of a control mesh and the principles to define a control mesh are essentially the same as for curve networks which are mostly used to define hull surfaces. In contrast to the common belief in the industry, it is analyzed that the approximation-based definition of a hull surface in terms of a control mesh simplifies modeling and improves the robustness compared to interpolation-based methods such as the commonly found interpolation of curve networks.

Rules, standards and regulations have to be observed in every step of the ship design process. Ignoring these constraints in any case leads to higher costs going along with potentially lower product quality. Numerous investigations have shown that product data model correction activities require considerable resources (man-hours and although money = cost) to obtain an acceptable quality level, and in the worst case, a redesign of potentially larger parts of the ship structure has to be performed. Computer-aided design systems offer a large set of functions to define a product data model. However, in the current situation, these tools are not capable to fully ensure the correctness of the product data model while observing the relevant quality criteria which are generally shipyard specific as they are mainly imposed by the production facilities. A quality management system is introduced which is based on the ISO 10303-59 focusing on quality criteria to be applied for an efficient ship structure production process. The functions of the system will be demonstrated on weldability criteria. These criteria demand notches at distinctive constellations of components depending on their function and, for example, minimum distances and angles between structural parts due to welding processes and material requirements. As an additional criterion, sufficient excess material has to be assigned to plate edges functioning as block boundaries to allow for the correction of inaccuracies in the production process at even late stages. The integration of the product data quality management algorithms with the computer-aided design system, in this case AVEVA marine, shows an efficient correction of inapt data as the automatically detected errors can easily be fixed by means of a guided process including the visualization of the structural parts with the help of the computer-aided design system being applied for data modelling.

In reverse engineering (RE) there are several strategies, technologies and mathematical numerics involved from data acquisition system to surface fitting. This makes the reverse engineering methods always computationally expensive, time taking and more over error prone. Therefore, developing application specific RE method can offer the required quality with reasonable associated time and then cost. This paper presents a practical and efficient ship hull form reconstruction strategy which align the reverse engineering results into traditional hull form design procedures. The developed approach reads points from a set of unorganized noisy 3D point cloud and fits to cross-sectional curves network (transversal and waterline sections). It consists of several point cloud pre-processing functions, the curves fitting (interpolation and approximation) and presents different Non-Uniform Rational B-Spline (NURBS) surface fitting approaches from curves network. The point cloud pre-processing removes outliers and extracts transversal and waterline sections. It is also equipped with different functions to successfully filter and smooth point cloud so that it can be fitted to curves by interpolation or approximation. The suitability of different existing surface generations (lofting, patching and surface from curves network) are experimented based on cross-sectional curves. The developed approach is tested against two hull forms (scanned and manually generated) point cloud. The tests reveals that, the developed approach is time saving and suitable for hull form reconstruction.

For the modeling of the ship structure, computer-aided design systems are generally used. During the different phases of the ship structure modeling and production process, the correctness of the generated product model data has to be continuously preserved. The correct assignment of position numbers to steel parts, e.g., represents a fundamental requirement of the ship structure production management. According to this requirement, a quality criterion can be formulated, that all parts to be manufactured have to have a position number assigned to with the condition that only identical parts should have the same position number. Two parts are generally regarded to be identical when they have the same properties concerning material, thickness, and shape. Shape in this case includes the outer and the inner contours (holes). The current control mechanisms of the correctness of product model data are manual, drawings-based methods. A new approach has been developed to automatically check the identity of the ship structural parts already during the design phase. This mechanism allows the engineers to maintain the quality of the product model data before it will be handed on for further processing. The approach described in this article is based on the Fre´chet distance algorithm, which is generally used to assess how closely two continuously closed curves resemble each other. The results of the steel structural parts shape comparison are presented in a report. This report can be used to check the correctness of the position number assignments and by this contributes to the overall quality assurance mechanism to preserve a high quality of the product model data. Although errors can be avoided, which will otherwise be detected in later process phases, they have to be fixed with significant additional costs.

In this paper the scenario based optimization of the bulbous bow of the KRISO Container Ship (KCS) is presented. The optimization of the parametrically modeled vessel is based on a statistically developed operational profile generated from noon-to-noon reports of a comparable 3600 TEU container vessel and specific development functions representing the growth of global economy during the vessels service time. In order to consider uncertainties, statistical fluctuations are added. An analysis of these data lead to a number of most probable upcoming operating conditions (OC) the vessel will stay in the future. According to their respective likeliness an objective function for the evaluation of the optimal design variant of the vessel is derived and implemented within the parametrical optimization workbench FRIENDSHIP Framework. In the following this evaluation is done with respect to vessel's calculated effective power based on the usage of potential flow code. The evaluation shows, that the usage of scenarios within the optimization process has a strong influence on the hull form.

The 18th International Ship and Offshore Structures Congress (ISSC) was held on September 10–13 in Rostock with more than 230 participants from over 30 countries. After 1973, this was the second ti...

Operations of search and rescue are technically very complicated and cause a potential risk for the rescue team. Therefore a new, autonomously acting rescue system is now being under development. Two mathematical models are presented to compute the hydrodynamics of small twin-hull water craft during a search and rescue process at different sea states. Using three and six degrees of freedom they are capable of simulating the navigation of the controlled rescue boat from the parent ship to the person overboard. 3DOF model is validated by comparison with SIMMAN workshop data and results obtained from 6DOF model. Also a study is performed to evaluate the influence of boat parameters on the manoeuvrability.

The design process in the maritime industry is characterized by a close cooperation of many diverse partners working in parallel. In this phase, standardization is used to reduce costs, to improve quality, and to shorten time to market. In this paper, an electronic system for the definition, management, and application of standardized solutions for steel structural design is presented. Information about the approach to data modeling applied and the interaction with existing applications is given.

Mesh generation methods for potential flow calculations require appropriate descriptions of the ship hull surface. The IGES standard is a widely used format in the shipbuilding industry for the exchange of ship hull forms. In this paper methods are presented to prepare ship hull form descriptions based on IGES files which are later be used for potential flow calculations. Two major problems are solved: topology recovery and knuckle detection.

Coordination procedures in commercial ship design, production, and procurement are widely predominantly analyzed fields. While deadlines become shorter and shorter, the complexity of modern commercial vessels increases steadily, so that these information systems are more and more indispensable for integration in maritime industry. Based on a detailed evaluation of integrating the upstream and downstream data flows, this paper describes the current implementation states under the collaborative environment concept and establishes the future integration network for shipbuilding.

The integration of software tools used in design and production of commercial ships is regarded a key issue with respect to product optimization and overall business success. To overcome this problem CAE-systems are integrated with help of adapters to a networked information infrastructure. The overall system architecture is outlined and the underlying ERM is discussed to show the complexity of a product model suitable to support ship design and production. Data exchange scenarios are described which demonstrate the integration of different shipbuilding specific systems: e.g. NAPA Steel and the analysis tool POSEIDON by Germanischer Lloyd. The implementation of an adapter supporting the STEP protocol AP214 (Core data for automotive mechanical design processes) serves to show the potential of this well supported protocol in the shipbuilding context.

Computer aided design (CAD) models are the starting point for many downstream applications such as mesh generation, structural/fluid/thermal analysis, rapid prototyping, numerical controlled machining, casting, computer graphics. Each of these downstream applications are strongly dependent on the accuracy and consistency of the input geometry, but due to numerical problems, imprecise design, software idiosyncrasies, or data exchange issues, the surface patches produced at the CAD step may abut within unpredictable tolerances, resulting in gaps, cracks, holes, overlaps, T-connections, invalid topology and inconsistent orientation which resulted in elusive automatic grid generation. In this paper, an automatic CAD processing tool based on a powerful software development platform (Open CASCADE Technology) is presented to reduce the amount of time and cost associated with cleaning/repairing CAD geometric data for grid generation. Geometries are read from IGES file format, and translated to an internal representation for processing (shape fix followed by sewing) and finally exported in STL, STEP and IGES file formats. The tool automatically detects and heals commonly found geometrical and topological errors. As the main target is automatically repairing CAD data format errors prior to mesh generation, many test cases are performed for different kind of geometries to check the algorithm consistency and robustness. Different CAD inconsistencies are considered to check the accuracy and efficiency of the tool. It is shown that improvement in terms of time and cost can be achieved.