Thesis (M.S.)--Naval Postgraduate School, 2003. / Title from title screen (viewed Aug. 3, 2004). "March 2003." Includes bibliographical references (p. 71-74). Also issued in paper format.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Fotis Papoulias. Includes bibliographical references (p. 73). Also available online.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Fotis Papoulias. Includes bibliographical references (p. 67-69). Also available online.

Thesis (M.S. in Naval Architecture and Marine Engineering and M.S. in Mechanical Engineering)--Massachusetts Institute of Technology, 2002. / Includes bibliographical references (p. 57). Also available online.

Green water problem and its loading effects on high speed containerships was investigated with the purpose of developing a modelling framework that can practically guide naval architects to a better understanding of this problem and improvements in design. The research began by reviewing extensive publications relevant to the understanding of green water, limitations in the ways the problem had been addressed and establishing a methodology that could effectively unlock the physics and efficiently solve the problem. As a first step, a summarised background to how green water started, developed and finally took place was presented. An experimental programme was then implemented in order to observe the occurrence and to explore the physics behind these events. From the outcome of the experiments, it was obvious that green water modelling could be developed and solved by Computational Fluid Dynamics (CFD) technique through Volume of Fluid (VoF) method. To provide a starting point for this research, theoretical background of CFD was briefly introduced. Furthermore, in order to validate this approach, two benchmark tests were implemented and compared with published experimental data. It showed that in both cases, the simulation could accurately reproduce the results obtained from experiments. Following this analysis, research continued to expand the CFD simulation to modelling of green water. Due to the complex and random nature of green water, development of the simulation framework was semi-empirical and based partly on experimental data. A pure theoretical approach could have been adopted. However, taking into consideration current limitations in ship motion prediction theories and sensitivity of green water to elemental factors, it was justified that semi-empirical approach was appropriate. The simulation was conducted and the output results were compared with experimental results for a variety of test conditions that involved ship velocity, wave height and period. Good agreement between simulation and experiment was obtained. For all loading cases, experimental results were reproduced fairly well. This suggested that the modelling framework was adequate for all practical purposes. Investigation was also conducted on a series of rectangular breakwaters that were fitted on the forecastle deck. Changes in water behaviour and loading following changes in the breakwater were well reflected. This implied that instead of a rectangular breakwater, the simulation model could also be applied to other types of breakwaters. The results suggested that the simulation methodology has many practical applications. Within naval architecture, it can be used to perform parametric studies in order to select an optimal design of breakwater for a ship. In other sectors such as coastal engineering, the methodology can be adopted to investigate the interaction between water surge and a seawall or offshore breakwater. In conclusion, it was found that the developed modelling framework shows potential for simple modelling of green water in which the behaviour of the water and its loading effects could be well reflected. It was further concluded that, provided appropriate principles are applied, the methodology has potential for other engineering applications. While it is acknowledged that current model may be limited by its semi-empirical basis and issues associated with computational requirements, it is noted that considerable possibilities for future research and development remains to be explored.

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To meet the demands for increasing the speed and improving the seakeeping behaviour of commercial and naval ships, this thesis investigates a new type of ship configuration - The Trimaran Displacement Ship, it features a slender centre hull and two small side hulls. The design methodology and hydrodynamic performance of this new ship concept has been investigated through design studies, model experiments and theoretical analysis. Potential advantages of the trimaran ship are, lower wavemaking resistance at high speed, larger deck area, and improved seakeeping behaviour compared with existing ship types. Firstly, existing marine vessel types, both monohulls and multihulls, are reviewed with regard to their advantages and limitations. The new trimaran concept and its background is then described from its initiation by a desire of inheriting advantages and avoiding limitations of these existing ship types. Namely, achieving the low resistance of slender monohulls and large deck area of multihulls, whilst eliminating the speed limit of conventional monohulls and the stiff roll motion of catamarans. The review of the trimaran ships design studies shows the potential applications of this new concept in commercial and naval roles. The feasibility of the new concept and the methodology required for its design are investigated through the concept design studies of. a trimaran fast ferry (Figure 1) and the hull form design for a trimaran model ship (Figure 2) for seakeeping experiments. This provides an initial view on the design procedure and basic design considerations for the trimaran ship. The parametric study in the trimaran ferry design gives the basic parameters for trimaran hull forms. Hydrodynamic performance of the trimaran ship has been investigated through model experiments and theoretical analysis on seakeeping, resistance, and manoeuvrability. Good agreements between theoretical predictions and model experiments have been achieved. This shows the merit of the computer programs developed during the investigation so they can be used in future trimaran ship designs for hydrodynamic performance assessments. A three dimensional theory is used in the trimaran motion analysis. Roll damping characteristics of the trimaran ship has been examined by including viscous effects in roll damping which can be derived either by simulating damping data from free decay experiments or by direct computation, that has been shown to improve the roll motion predictions. Systematic investigation into the wavemaking resistance of the trimaran ship reveals the relationship between the side hull configuration and the resistance performance. Wave cancellation effects can be achieved when the side hulls are appropriately located to further reduce the wavemaking resistance of the trimaran ship. A manoeuvrability study concentrated on the effect of the side hulls on the turning ability of the trimaran ship as well as the effect of side hull propulsion. Following the hydrodynamic analysis of the trimaran ship, the design procedure and general considerations in trimaran ship design distinctive from other ship types are proposed and discussed with particular reference to stability and hydrodynamic performance. Trimaran hull form options are also discussed alongside some other design considerations. The thesis concludes that the new trimaran displacement ship shows superior characteristics in some hydrodynamic aspects over existing marine vessels, particularly in resistance and seakeeping, and therefore there is no reason why this novel concept can not be translated into real ships.

On December 17th 2002 the World Meteorological Organization issued a statement according to which the global mean surface temperature has risen and consequently 2002 was the warmest year in the 1961-2002 period.  Positive sea surface temperature anomalies across much of the land and sea surface of the globe in general contributed to the near record temperature ranking for the year along with climate anomalies in many regions across the globe.  Climate change as a result of global warming is a worldwide occurring phenomenon which the experts have only recently started to understand and which affects and significantly will affect us in the near future.  The effects of climate change have been somehow neglected by the ship and offshore related academic and research communities. In the case of thermal effects on ships structures, unless the problem solved is temperature dependent, this type of stress has often been neglected and not been taken into account in most types of analysis.  The most likely reason behind this would seem to be that the stresses produced from temperature changes would be too small to be taken into account compared with still water loads or wave bending stresses.  This is not the case though.  Records exist of ships having broken in half while moored in still water and major hull factures occurred in still water while the temperature was changing as it can be seen from the relevant published literature.  Very little work on thermal stress on ship structures has been published since the 1950s and 1960s and no work has been done that considers temperature effects on ultimate strength. Research undertaken aims to incorporate temperature effects on existing ultimate strength formulation by using a thermal stress approach, compare and use recently proposed corrosion models to model corrosion effects on ultimate strength and provide a foundation on which reliability analysis could then be performed for Tanker/FPSO structures operating in the North Sea.  After comparing a number of possible approaches that would enable to loading components to be combined in a stochastic fashion, the loading part of the reliability analysis is handled using extreme wave statistics and the Ferry Borges-Castanheta load combination method. Annual reliability indices and probabilities of failure are calculated for hogging and sagging conditions using both time-variant and time-invariant approaches and a variety of reliability analysis approaches showing the effects of temperature along with partial Safety Factors for all variables taken into account.

Thesis (Master)--İzmir Institute of Technology, İzmir, 2006. / Keywords: concept ferry design, İzmir feryy design. Includes bibliographical references (leaves. 68-70).