Approved for public release, distribution is unlimited / Numerous optimization problems involve systems with multiple and often contradictory criteria. Such contradictory criteria have been an issue for marine/naval engineering design studies for many years. This problem becomes more important when one considers novel ship types with very limited or no operational record. A number of approaches have been proposed to overcome these multiple criteria design optimization problems. This Thesis follows the Parameter Space Investigation (PSI) technique to address these problems. The PSI method is implemented with a software package called MOVI (Multi-criteria Optimization and Vector Identification). Two marine/naval engineering design optimization models were investigated using the PSI technique along with the MOVI software. The first example was a bulk carrier design model which was previously studied with other optimization methods. This model, which was selected due to its relatively small dimensionality and the availability of existing studies, was utilized in order to demonstrate and validate the features of the proposed approach. A more realistic example was based on the "MIT Functional Ship Design Synthesis Model" with a greater number of parameters, criteria, and functional constraints. A series of optimization studies conducted for this model demonstrated that the proposed approach can be implemented in a naval ship design environment and can lead to a large design parameter space exploration with minimum computational effort. / Lieutenant Junior Grade, Turkish Navy

This thesis provides a means to estimate the physical and performance characteristics of a preliminary cruise ship design. The techniques utilized to estimate these characteristics are showcased in the user-friendly interface known as the Cruise Ship Analysis Tool (CSAT). Using the CSAT, the implications that design feature decisions in the preliminary design stage have on a cruise ship’s profitability is analyzed. Then, the most profitable design feature assemblage among a finite number of varying design feature combinations is estimated and compared among cruise ship designs with different passenger carrying capacities. Profitability is analyzed using the measure of merit (MOM) known as net present value (NPV). If a preliminary cruise ship design has a positive NPV at a reliable rate of return and ship operating life, the design is considered to be a profitable investment if implemented. The greater the NPV, the more profitable the investment is considered to be.

Cette thèse présente un framework d’optimisation pour la conception hydrodynamique de forme d’hydrofoils. L’optimisation d’hydrofoil par simulation implique des objectifs d’optimisation divergents et impose des compromis contraignants en raison du coût des simulations numériques et des budgets limités généralement alloués à la conception des navires. Le framework fait appel à l’échantillonnage séquentiel et aux modèles de substitution. Un modèle prédictif est construit en utilisant la Régression par Processus Gaussien (RPG) à partir des données issues de simulations fluides effectuées sur différentes géométries d’hydrofoils. Le modèle est ensuite combiné à d’autres critères dans une fonction d’acquisition qui est évaluée sur l’espace de conception afin de définir une nouvelle géométrie qui est testée et dont les paramètres et la réponse sont ajoutés au jeu de données, améliorant ainsi le modèle. Une nouvelle fonction d’acquisition a été développée, basée sur la variance RPG et la validation croisée des données. Un modeleur géométrique a également été développé afin de créer automatiquement les géométries d’hydrofoil a partir des paramètres déterminés par l’optimiseur. Pour compléter la boucle d’optimisation,FINE/Marine, un solveur fluide RANS, a été intégré dans le framework pour exécuter les simulations fluides. Les capacités d’optimisation ont été testées sur des cas tests analytiques montrant que la nouvelle fonction d’acquisition offre plus de robustesse que d’autres fonctions d’acquisition existantes. L’ensemble du framework a ensuite été testé sur des optimisations de sections 2Dd’hydrofoil ainsi que d’hydrofoil 3D avec surface libre. Dans les deux cas, le processus d’optimisation fonctionne, permettant d’optimiser les géométries d’hydrofoils et confirmant les performances obtenues sur les cas test analytiques. Les optima semblent cependant être assez sensibles aux conditions opérationnelles. / This thesis presents a practical hydrodynamic optimization framework for hydrofoil shape design. Automated simulation based optimization of hydrofoil is a challenging process. It may involve conflicting optimization objectives, but also impose a trade-off between the cost of numerical simulations and the limited budgets available for ship design. The optimization frameworkis based on sequential sampling and surrogate modeling. Gaussian Process Regression (GPR) is used to build a predictive model based on data issued from fluid simulations of selected hydrofoil geometries. The GPR model is then combined with other criteria into an acquisition function that isevaluated over the design space, to define new querypoints that are added to the data set in order to improve the model. A custom acquisition function is developed, based on GPR variance and cross validation of the data.A hydrofoil geometric modeler is also developed to automatically create the hydrofoil shapes based on the parameters determined by the optimizer. To complete the optimization loop, FINE/Marine, a RANS flow solver, is embedded into the framework to perform the fluid simulations. Optimization capabilities are tested on analytical test cases. The results show that the custom function is more robust than other existing acquisition functions when tested on difficult functions. The entire optimization framework is then tested on 2D hydrofoil sections and 3D hydrofoil optimization cases with free surface. In both cases, the optimization process performs well, resulting in optimized hydrofoil shapes and confirming the results obtained from the analytical test cases. However, the optimum is shown to be sensitive to operating conditions.

Thesis (M.S.)--Kungl. Tekniska högskolan, 2002. / Includes bibliographical references (p. 125-126). Also available online via the Swedish National Road and Transport Research Institute web site (www.vti.se).

The main objective of this project is to investigate the applicability of the IMO second-generation intact stability criteria in enhancing the process of designing fishing vessels, which often face stability challenges due to their narrow hulls and harsh operating environments. The study involves analyzing the impact of these criteria, specifically focusing on dead ship conditions and Level 1 and Level 2 excessive acceleration criteria, on the design of three fishing vessels. Through thorough theoretical examination and practical assessment, the research seeks to provide naval architects with valuable insights into designing safer and more stable fishing vessels. The investigation also explores the potential benefits of incorporating bilge keels to mitigate lateral acceleration effects, aiming to enhance crew safety. Finally, a discussion of the computation results is held, followed by a conclusion. / Huvudsyftet med detta projekt är att undersöka tillämpbarheten av IMO:s andra generationens kriterier för intaktstabilitet för att förbättra processen med att designa fiskefartyg. Denna typ av fartyg har ofta flera stabilitetsutmaningar på grund av deras smala skrov och krävande driftsmiljöer. Studien innefattar att analysera effekterna av dessa kriterier, med särskild fokus på "dead ship" villkor samt nivå 1- och nivå 2-kriterierna för kraftiga acceleration, på designen av tre fiskefartyg. Genom teoretisk granskning och praktisk bedömning ämnar forskningen ge fartygskonstruktörer insikter för att designa säkrare och mer stabila fiskefartyg. Undersökningen utforskar också de potentiella fördelarna med att inkludera slingerkölar för att mildra effekterna av lateral acceleration och därmed öka besättningens säkerhet. Rapporten avslutas med en diskussion kring beräkningsresultaten, följt av en slutsats.

Depuis les années 1980, des épaves de grands navires construits à clin de la fin du Moyen-Age ont été découvertes sur les littoraux des mers septentrionales et occidentales. Elles ont régulièrement suscité individuellement un intérêt de la communauté scientifique en regard de leur architecture, puisque la fin du Moyen-Age correspond historiquement à l’apparition puis à la diffusion et à l’adaptation de la construction navale à franc-bord d’origine méditerranéenne en Europe du Nord et de l’Ouest. Pourtant, la comparaison des différentes épaves entre elles pour étudier les développements de la construction navale à clin de cette période est très récente et généralement rattachée à l’analyse des épaves nouvellement trouvées.Cette thèse étudie l’ensemble des navires de plus de 20 m de long susceptibles, par leur architecture, d’avoir évolué en haute mer sur les routes du commerce lointain. En regard du contexte technique et historique, cette étude est limitée géographiquement aux mers nordiques et chronologiquement au Moyen-Age tardif et au début de la période moderne.Le navire résulte à la fois des technique de construction navale et de la demande de ses commanditaires. Durant la période d’étude envisagée dans la thèse, les marchands, qui sont également les affréteurs, constituent les principaux armateurs avec les gens de mer, marins et capitaines, qui régulièrement sont propriétaires en totalité ou en partie des grands bâtiments.De ce fait, le contexte historique, affectant les activités de commerce et de transport, contribue à expliquer les développements de la construction navale. De plus, l’analyse technique des épaves permet de comprendre comment les charpentiers de marine ont pu répondre à la demande de ces propriétaires. Pour cela, la reconstitution des épaves, comme celle de l’Aber Wrac’h 1(France), est essentielle, car les données relatives à la construction, la conception et la forme des navires fournissent des éléments de comparaison scientifique fiables en regard des typologies chronologiques et régionales et permettent de replacer le navire dans son contexte historique et socio-économique. / Since the 1980s, several wrecks of large clinker ships adting from the late Middle Ages were found on the coasts of Northern and Atlantic seas. The scientific community was regularly interested in the architecture of each site as the late Middle Ages historically corresponds to the appearance, dissemination and adaptation of the carvel shipbuilding from the Mediterranean in Northern and Western Europe. Yet the comparison of the different wrecks themselves to study the development of the clinker shipbuilding of this period is recent and usually linked to the analysis of newly found wrecks.This thesis explores all vessels over a length of 20 meters, which were able, according to their architecture, to sail on open seas for long-distance trade. Due to the technical and historical context, this study is limited geographically to the nordic seas and chronologically to the Late Middle Ages and early modern period.The ship results from the shipbuilding technology and the demand of its owners. During the late Middle Ages, the merchant class, which was the principal user, was also the main shipowner with the seafarers, sailors and captains, who regularly owned all or part of large vessels.Therefore, the historical context, affecting trade and transport activities, helps to explain the developments in shipbuilding. Therefore, technical analysis of wrecks allows understanding how the shipwrights and carpenters could meet the demand of those owners. Hence, there construction of the wreck, such as Aber Wrac’h 1 (France), is essential because the data about the building, design and shape of the vessels provide reliable scientific information for comparison in terms of chronological and regional typologies and help to place the ship in its historical, environmental and socio-economic context.