Thesis (M.S. in Physical Oceanography) Naval Postgraduate School, December 2001. / "December 2001". Thesis advisor(s): Durkee, Philip A . ; Paduan, Jeffrey D. Includes bibliographical references (p.53-54). Also available online.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Robert W. Ashton. Includes bibliographical references (p. 83-84 ). Also available online.

No description available.

Since the end of the cold war the United States is the single dominant naval power in the world. The emphasis of the last decade has been to reduce cost while maintaining this status. As the Navy's infrastructure decreases, so too does its ability to be an active participant in all aspects of ship operations and design. One way that the navy has achieved large savings is by using the Military Sealift Command to manage day to day operations of the Navy's auxiliary and underway replenishment ships. While these ships are an active part of the Navy's fighting force, they infrequently are put into harm's way. The natural progression in the design of these ships is to have them fully classified under current American Bureau of Shipping (ABS) rules, as they closely resemble commercial ships. The first new design to be fully classed under ABS is the T-AKE. The Navy and ABS consider the T-AKE program a trial to determine if a partnership between the two organizations can extend into the classification of all new naval ships. A major difficulty in this venture is how to translate the knowledge base which led to the development of current military specifications into rules that ABS can use for future ships. The specific task required by the Navy in this project is to predict the inherent availability of the new T-AKE class ship. To accomplish this task, the reliability of T-AKE equipment and machinery must be known. Under normal conditions reliability data would be obtained from past ships with similar mission, equipment and machinery. Due to the unique nature of the T-AKE acquisition, this is not possible. Because of the use of commercial off the shelf (COTS) equipment and machinery, military equipment and machinery reliability data can not be used directly to predict T-AKE availability. This problem is compounded by the fact that existing COTS equipment and machinery reliability data developed in commercial applications may not be applicable to a military application. A method for deriving reliability data for commercial equipment and machinery adapted or used in military applications is required. A Reliability Transform Method is developed that allows the interpolation of reliability data between commercial equipment and machinery operating in a commercial environment, commercial equipment and machinery operating in a military environment, and military equipment and machinery operating in a military environment. The reliability data for T-AKE is created using this Reliability Transform Method and the commercial reliability data. The reliability data is then used to calculate the inherent availability of T-AKE. / Master of Science

This thesis presents a process and tool that generates representative preliminary ship models and arrangements for use in vulnerability analysis in the Concept and Requirements Exploration (CandRE) process used at Virginia Tech. CandRE uses a Multi-Objective Genetic Optimization (MOGO) to explore the design space for non-dominated ship design solutions based on design effectiveness, risk, and cost. Vulnerability is assessed as part of the CandRE using a Preliminary Arrangements and Vulnerability (PAandV) model. Representative ship arrangements for specified combinations of ship system options are created based on operability needs, ship mission needs, and improved vulnerability. These are then analyzed for vulnerability and are used to calculate a representative Overall Measure of Vulnerability (OMOV) which is used to calculate the Overall Measure of Effectiveness (OMOE) in the MOGO. / Master of Science

The naval ship concept design process often embraces novel concepts and technologies that carry with them an inherent risk of failure simply because their application is the first of its kind. Failure is recognized by gaps between actual and required measures of performance, exceeded budgets, and late deliveries. These risks can be defined and quantified as the product of the probability of an occurrence of failure and a measure of the consequence of that failure. Since the objective of engineering is to design and build things to meet requirements, within budget, and on schedule the first time, it is important to consider risk, along with cost and performance, in trade assessments and technology selections made during concept design. To this end, this thesis presents a simplified metric and methodology for measuring the risk of ship design concepts as part of a Multi-Objective Optimization tool for naval ship concept design. The purpose of this tool is to provide a consistent format and methodology for multi-objective decisions based on dissimilar objective attributes, specifically effectiveness, cost and risk. This approach provides a more efficient and robust method to search the design space for optimal concepts than the traditional "ad hoc" naval ship concept design process where selection and assessment are often based on experience, design lanes, rules-of-thumb and Imagineering. This thesis begins with the results of a literature and information search that investigates and describes risk, engineering systems safety, and state of the art risk analysis techniques currently in practice. Based on this background, a simplified metric and methodology is developed to calculate, quantify, and compare relative overall risk in a naval ship design optimization. To demonstrate this method, a naval ship risk register is developed for a notional ship design. This register identifies potential cost, performance, and schedule risk issues. Risk item descriptions are further defined as a function of the design parameters (DPs) considered for the notional ship. Risk Factors (RF) are calculated for each risk item based on the DP selection. Each RF is the product of a Probability of Failure Occurrence (PF) and Potential Consequence of Failure (CF). An Overall Measure of Risk (OMOR) function is developed to measure the level of overall risk for a single concept design based on DP selections. A ship design case study is performed incorporating the OMOR function and risk items into a ship synthesis model capable of calculating cost, performance, and effectiveness. This case study uses a Multi-Objective Genetic Optimization (MOGO) to identify and define a series of non-dominated cost-effectiveness frontiers for a range of risk (OMOR) values. This new method for ship design optimization provides a novel approach and consistent format for multi-objective decision-making based on three dissimilar objective attributes: effectiveness, cost, and risk. / Master of Science

The serious consequence of ship collisions necessitates the development of regulations and requirements for the subdivision and structural design of ships to reduce damage and environmental pollution from collision, and improve safety. The on-going revision of IMO regulations on oil outflow performance and damage stability in grounding and collision is focused on a transition to probabilistic performance-based standards. This thesis addresses one aspect of this problem, a simplified collision model sufficient to predict collision damage, and fast enough to be used in probabilistic analysis requiring thousands of collision simulations. The simplified collision model (SIMCOL) developed and evaluated in this thesis is based on a time domain simultaneous solution of external dynamics and internal deformation mechanics. The external sub-model uses a three-degree of freedom system for ship dynamics. The internal sub-model determines reacting forces from side and bulkhead structures using mechanisms adapted from Rosenblatt and McDermott, and absorbed energy by decks, bottoms and stringers calculated using the Minorsky correlation as modified by Reardon and Sprung. SIMCOL is applied to a series of collision scenarios. Results are compared with MIT's DAMAGE, a Danish Technical University (DTU) model and ALPS/SCOL. SIMCOL provides a fast, consistent and reasonable result for ship collision analysis. An actual collision case is used in an initial attempt to validate the model. This research is sponsored by the Society of Naval Architects and Marine Engineers (SNAME) and the Ship Structure Committee (SSC). / Master of Science

The serious consequence of ship collisions necessitates the development of regulations and requirements for the subdivision and structural design of ships so that damage and environmental pollution is reduced, and safety is improved. A simplified collision model (SIMCOL) is currently being developed at Virginia Tech to conduct probabilistic analysis of damage in ship collisions and ultimately optimize ship structural designs to improve crashworthiness. Collision data for validation of SIMCOL is very difficult to obtain, and model testing is very costly. Finite Element Analysis (FEA) provides an alternative to physical validation that can be used to increase confidence and insight in simplified model results. This thesis develops a complete methodology for ship-to-ship collision simulations using the explicit non-linear FE code LS-DYNA3D. Various modeling alternatives are considered. The ability to model a complete ship-to-ship collision is developed incrementally starting with bow collisions with a rigid wall. A super-element (intersection model) approach is considered to increase the calculation speed of bow models. A conventional fine mesh finite element bow model is also developed. Results from both models are compared with each other, and with a closed-form calculation from Pedersen. A fine mesh model is developed for a struck tanker cargo section and integrated in a total ship framework modeling external dynamics and ship-to-ship contact. A series of collision scenarios is simulated using the conventional bow model and a rigid bow model striking a double hull tanker. Results are compared with SIMCOL, DAMAGE, DTU and ALPS/SCOL models. LS-DYNA provides detailed and reasonable results for ship collision analysis and comparison to increase confidence in simplified models. / Master of Science

Thesis (M.Eng.)--Memorial University of Newfoundland, 2004. / Bibliography: leaves 188-190.

Bränsle är en av det största kostnaden för sjöfart och ny teknik tas fram för att spara bränsle. Men det finns potential att tillverka bränsle på kryssningsfartyg. En av de största utgifterna för att tillverka biogas iland är uppvärmning av substratet, denna kostnad kan elimineras på fartyg genom att använda spillvärme från motorer och ångsystem.   Detta arbete undersöker möjligheten att producera biogas av toalett- och matavfall som dagligen skapas på kryssningsfartyg, vilka komponenter som behövs samt beräkningar av utrymme de skulle ta och hur stor mängd gas som kan tänkas produceras. Rapporten utfördes genom att undersöka hur biogas produceras i land, vilka är de vanligaste teknikerna som används idag och om de är teknisk möjliga att ha på kryssningsfartyg. För att räkna ut gaspotential samt volym för tankar och reaktor har data samlat in från fyra kryssningsfartyg, data för toalettavfall har tagit från land. Resultatet av beräkningarna blev att potential att tillverka biogas finns men att mängden gas inte kan motivera kostnaden för att installera en biogasanläggning på ett kryssningsfartyg. / Fuel is one of the biggest costs in shipping today, and new technologies are being developed to save fuel. But there is potential to make fuel today aboard cruise ships. One of the biggest expenses in making biogas on land is the heating of the substrate, this cost can be eliminated on ships by using waste heat from engines and steam systems. This report explores the possibility of producing biogas by using toilet and food waste that is created daily aboard cruise ships. What components are needed, calculations of the space they would take and how much gas could be produced. The report was conducted by examining how biogas is produced on land, what are the most common technologies used today? And if they are technically possible aboard a cruise ship? To calculate gas potential, tank and reactor volume. Data has been collected from four cruise ships. The results show that it is possible to create biogas. But that the amount of gas could not justify the cost of building a biogas plant aboard cruise ships.