<p>A literature search was conducted to determine to the type and scope of decision methodologies employed in selection of a ship propulsion plant by the commercial and naval shipbuilding communities as well as methodologies used in other industries. The methodologies were categorized and evaluated by the author with regard to ability to accommodate multi-attribute decision-making involving attributes of a qualitative and quantitative nature inherent in propulsion plant selection.</p> <p> An alternative decision methodology employing the analytical hierarchy process (AHP) combined with selection criteria and sub-criteria unique to the shipbuilding industry was proposed which offers improvements in consistency and quality of judgements and accountability over current methodologies. A case study involving a 700 foot RoRo vessel design was developed to demonstrate how the alternative methodology could be applied. A three level decision hierarchy was developed to evaluate four propulsion plant alternatives involving gas turbine, low speed diesel and medium speed diesel prime movers.</p> <p> The results obtained using the proposed methodology were analyzed and sensitivity analyses were prepared assessing the range of sub-criteria weights assigned by the author over which the plant selection would be valid. A description of the investigation, selection criteria and sub-criteria, benefits, and recommendations for future efforts is included.</p> / Master of Science

“Out Here” is a fictional account of a daughter’s voyage across the Pacific Ocean as a passenger aboard a working containership with her father.

Most digital control architectures for power system applications require synchronization with the distribution system voltage. Therefore, a phase-locked loop (PLL), implemented in a DSP, is generally among the digital control blocks of the control system. The PLL analyzes the bus voltage and provides power system information for some of the other blocks to do further calculation. Thus, the performance of the PLL has a broad impact on the system performance. Small-scale power systems, such as naval systems, pose a challenging environment for PLL design due to voltage distortion and variation in the fundamental frequency that is large as compared to large terrestrial systems. Our objective is to improve the accuracy of the PLL digital block and hence enhance the digital control system. This research compares two PLL algorithms, as well as the use of a PI controller or lag controller with respect to their steady state and transient performance.

The overall objective of this thesis is to develop, validate and assess a probabilistic collision damage model to support ongoing work by the Society of Naval Architecture and Marine Engineering (SNAME) Ad Hoc Panel #6 and IMO working groups. It is generally agreed that structural design has a major influence on tanker oil outflow and damaged stability in grounding and collision, but crashworthiness is not considered in present regulations. The proposed methodology provides a practical means of considering structural design in a regulatory framework, and when implemented would improve the safety and environmental performance of ships. This thesis continues the development and applies a Simplified Collision Model (SIMCOL) to calculate damage extent (transverse, vertical and longitudinal) and oil outflow in ship collisions. The primary contribution of this thesis is the development and validation of a theory for the determination of energy absorbed in longitudinal extent of damage, and the implementation of the theory within SIMCOL. SIMCOL is sufficiently fast to be applied to thousands of collision cases as is required for a probabilistic analysis. The following specific tasks were completed using SIMCOL in support of this project: Completed the development of SIMCOL Version 3.0 including: 1) Deformable Bow sub model 2) Implementation and validation of theory for the determination of energy absorbed in longitudinal extent of damage. • Developed the capability to model collision events using LSDYNA. • Validated Virginia Tech LSDYNA ship collision modeling procedure. • Validated SIMCOL using real collision data, and probabilistic collision data for penetrating collisions. / Ph. D.

This dissertation explores mathematical programming optimization models and algorithms for routing and scheduling ships in a maritime transportation system. Literature surveyed on seaborne transportation systems indicates that there is a scarcity of research on ship routing and scheduling problems. The complexity and the overwhelming size of a typical ship routing and scheduling problem are the primary reasons that have resulted in the scarcity of research in this area. The principal thrust of this research effort is focused at the Kuwait Petroleum Corporation (KPC) Problem. This problem is of great economic significance to the State of Kuwait, whose economy has been traditionally dominated to a large extent by the oil sector. Any enhancement in the existing ad-hoc scheduling procedure has the potential for significant savings. A mixed-integer programming model for the KPC problem is constructed in this dissertation. The resulting mathematical formulation is rather complex to solve due to (1) the overwhelming problem size for a typical demand contract scenario, (2) the integrality conditions, and (3) the structural diversity in the constraints. Accordingly, attempting to solve this formulation for a typical demand contract scenario without resorting to any aggregation or partitioning schemes is theoretically complex and computationally intractable. Motivated by the complexity of the above model, an aggregate model that retains the principal features of the KPC problem is formulated. This model is computationally far more tractable than the initial model, and consequently, it is utilized to construct a good quality heuristic solution for the KPC problem. The initial formulation is solved using CPLEX 4.0 mixed integer programming capabilities for a number of relatively small-sized test cases, and pertinent results and computational difficulties are reported. The aggregate formulation is solved using CPLEX 4.0 MIP in concert with specialized rolling horizon solution algorithms and related results are reported. The rolling horizon solution algorithms enabled us to handle practical sized problems that could not be handled by directly solving the aggregate problem. The performance of the rolling horizon algorithms may be enhanced by increasing the physical memory, and consequently, better solutions can be extracted. The potential saving and usefulness of this model in negotiation and planning purposes strongly justifies the acquisition of more computing power to tackle practical sized test problems. An ad-hoc scheduling procedure that is intended to simulate the current KPC scheduling practice is presented in this dissertation. It is shown that results obtained via the proposed rolling horizon algorithms are at least as good, and often substantially better than, results obtained via this ad-hoc procedure. / Ph. D.

Ship groundings are a low probability event, but can create severe environmental and financial consequences. The objective of this thesis is to provide knowledge and understanding of the grounded ship condition to salvors and ship owners so they can reduce the possible negative consequences of future ship groundings. There has been very little research on the motions of and loads on a grounded ship in waves. In this thesis, a model of the ground reaction forces due to the steady state motions of a grounded ship is developed. This model is derived from civil engineering applications but tailored to the stranded ship problem. The ground reaction sub-model is part of a ship motion model that predicts grounded ship motions and loads in waves. The model input specifies the static grounded equilibrium condition and static grounded forces. The model calculates steady state motions and loads around the equilibrium condition. This thesis describes a preliminary version of the full six degree of freedom model in which soil reactions are accounted for in two degrees of freedom, heave and pitch, assuming a rectangular shaped hull. Bottom types are categorized as sand, mud, coral and rock. The ship can be embedded or resting on the surface of the bottom. / Master of Science

This thesis describes and assesses a simplified tool for modeling underwater explosion shock effects during early naval ship concept design. A simplified fluid model using Taylor flat-plate theory is incorporated directly into the OpenFSI module code in Nastran and used to interface with the structural solver in Nastran to simulate a far-field shockwave impacting the hull. The kick-off velocities and the shock spectra captured in this computationally efficient module is compared to results from a high-fidelity CASE (Cavitating Acoustic Spectral Element) fluid model implemented with the ABAQUS/Nastran structural solver to validate the simplified framework and assess the sufficiency of this very simple but, fast approach for early stage ship design. / Master of Science

The use of computational fluid dynamics to investigate surface ship dynamics and characteristics has been growing during recent years. With technological advancements continuing in leaps and bounds more and more complex simulations are possible. The interests of this paper concern the numerical simulations of a surface effect ship which is a specific type of air cushion vehicle. The simulation work presented here attempts to replicate the model tests involving a generic surface effect ship and demonstrate the value of numerical simulations in understanding air cushion vehicles. The model tests consist of a surface effect ship running through a range of Froude numbers in calm seas and a variety of wave cases. The numerical simulations were developed using CD-adapcos's STAR-CCM+ to model the surface effect ship characteristics and dynamics. The pressurized air cushion and flexible, dynamic seals are of the greatest importance when modeling a surface effect ship; however, some idealizations had to be made. The air cushion fans are represented as constant momentum sources while the seals are represented as shortened and rigid. Throughout the simulations drag, pitch, and heave were constantly monitored for comparison purposes with the model tests. It was found that the rigid skirt approximation accounts for a large portion of error when comparisons were made between the numerical and analytical data. Furthermore, it would be impossible to accurately represent the surface effect ship dynamics in waves with this approximation. An alternative method to modeling the skirts was investigated which would include the use of a porosity function. It was found that the porosity skirt model would allow for cushion pressure to be maintained while limiting the interaction of the rigid skirt and the free surface. The full implementation of porous skirts on the surface effect ship is a difficult challenge as numerical instabilities arise. However, implementing the porous skirt would lead to more accurate calm water simulations and the ability to model the surface effect ship in wave cases. / Master of Science

This thesis presents an analysis method for determining the whipping response of a hull girder to underwater explosion (UNDEX) bubble pulse loading. A potential flow-based UNDEX bubble model capable of calculating the behavior of a migrating bubble for up to three pulses is developed. An approximate vertical plane ship vibration model is derived using fundamental beam theory by representing the ship as a free-free beam with varying cross-sectional properties along its length. The fluid-structure interaction is approximated using strip theory and the distant flow assumption. The most severe predicted whipping load conditions are applied to a MAESTRO finite element model of the ship as a quasi-static load case to determine the response of the structure to the whipping loads. The calculated hull girder bending moments are compared to the ultimate bending strength of the hull girder to determine if the girder will collapse. The analysis method is found to be a useful method for determining preliminary UNDEX-induced whipping design load cases for early-stage ship design. However, more detailed and accurate data is needed to validate and verify the predicted whipping responses. It is found that the most severe whipping loads occur as the result of an UNDEX event that occurs under the keel near midship and produces a bubble with a pulsation frequency similar to the natural vibration frequency of the ship in its third mode. Significant damage to the ship structure and hull girder collapse is possible as a result of these loads. / Master of Science

Detta examensarbete handlar om fartygsskydd och rollen som SSO på olika fartygstyper. Syftet med undersökningen var att ta reda på vilket sätt fartygstypen och fartområdet fartyget går i påverkar hur man ombord arbetar med fartygsskyddet och ISPS. Denna undersökning genomfördes under sommaren och hösten 2015 genom kvalitativa semistrukturerade intervjuer med SSO:erna på fyra fartyg av olika typ i olika fartområden. Fartygen i undersökningen består av ett kryssningsfartyg i oceanfart, ett tankfartyg i europafart, ett biltransportfartyg i oceanfart samt en färja i närfart. Resultatet av vår undersökning visar att det finns skillnader mellan både de undersökta fartygstyperna och fartområdena samt att detta påverkar hur de intervjuade SSO:erna uppfattar sin roll. Resultatet pekar på att den största skillnaden i organiseringen av fartygsskyddet finns mellan de två huvudtyperna av fartyg i studien, dvs. passagerarfartyg och lastfartyg, och att den skillnaden till stor del kan förklaras av besättningens storlek. / This thesis is about ship security and the role of the SSO on different types of vessels. The purpose of the survey was to find out how the ship type and trade area of the ship affects how the on-board work with security and ISPS is conducted. The study was carried out during the summer and autumn 2015 by making qualitative semi-structured interviews with the SSOs on four vessels of different type in different trade areas. The vessels in the survey consist of a cruise ship in ocean traffic, a tanker in European traffic, a car carrier in world-wide ocean traffic and a ferry in short voyage traffic. In the study it was concluded that there are differences between both the investigated vessel types and trade areas, and that this affects how the interviewees: the SSOs perceive their role. The result indicates that the largest difference in the organization of ship security is found between the two main types of vessels in the study, between passenger ships and cargo ships, and that this difference can largely be explained by the size of the crew.