Thesis (M.P.A.)--University of Hong Kong, 1994. / Includes bibliographical references.

Thesis (M.P.A.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

<p>The dissertation is divided into four separated parts.</p><p>Part 1 is a summary of the three following parts, supplemented with components from a more general point of view.</p><p>Part 2 deals with the shaping of sea-going vessels, delivered between 1935 and 1995. All of them with some form of connection to Sweden.</p><p>Part 3 is an analysis of the architecture of the white wooden fishing boat from the west of the Swedish coast.</p><p>Part 4 is a similar analysis of the steel fishing boat.</p><p>The term "ship architecture" has been chosen in the dissertation, instead of "design" or "naval architecture". Naval architecture is a wide-ranging subject which however does not embrace that which normally is included in the concept "architecture" as it is employed by art historians and architects. Design is usually an industrial production in great quantity of identical objects. While ships, with few exceptions, are unique like buildings.</p><p>Ship architecture is a subject which has barely been treated, either in Sweden or abroad.</p><p>The source material used in this study are the "general arrangements", blueprints, published in periodicals and the fotographs of newly-built ships. The main source has been The Scandinavian Shipping Gazette, which has been published weekly on a more or less regular basis since its inception in 1905. A number of architectural motifs are each dealt with separately.</p><p>The conclusion of the study is that two separate attitudes to ship architecture can be discerned during the period under investigation. During the first one the appearance of the ship has been significant for both builders and owners. The necessary skills have been readily available.</p><p>During the latter one (a shift occuring in the mid-1960s), interest in the appearance of the ship has disappeared, instead only effiency and economy are demanded. There is still a desire for aesthetics in passenger liners, but by that time, much of the old skilled workmanship has been lost.</p><p>However, there need remain any doubt about the willingness of the shipyards also today to agree to revisions for the sake of aesthetic appearance. If there was any interest in doing so and if it was delivered at an early stage of the newbuilding process.</p>

The dissertation is divided into four separated parts. Part 1 is a summary of the three following parts, supplemented with components from a more general point of view. Part 2 deals with the shaping of sea-going vessels, delivered between 1935 and 1995. All of them with some form of connection to Sweden. Part 3 is an analysis of the architecture of the white wooden fishing boat from the west of the Swedish coast. Part 4 is a similar analysis of the steel fishing boat. The term "ship architecture" has been chosen in the dissertation, instead of "design" or "naval architecture". Naval architecture is a wide-ranging subject which however does not embrace that which normally is included in the concept "architecture" as it is employed by art historians and architects. Design is usually an industrial production in great quantity of identical objects. While ships, with few exceptions, are unique like buildings. Ship architecture is a subject which has barely been treated, either in Sweden or abroad. The source material used in this study are the "general arrangements", blueprints, published in periodicals and the fotographs of newly-built ships. The main source has been The Scandinavian Shipping Gazette, which has been published weekly on a more or less regular basis since its inception in 1905. A number of architectural motifs are each dealt with separately. The conclusion of the study is that two separate attitudes to ship architecture can be discerned during the period under investigation. During the first one the appearance of the ship has been significant for both builders and owners. The necessary skills have been readily available. During the latter one (a shift occuring in the mid-1960s), interest in the appearance of the ship has disappeared, instead only effiency and economy are demanded. There is still a desire for aesthetics in passenger liners, but by that time, much of the old skilled workmanship has been lost. However, there need remain any doubt about the willingness of the shipyards also today to agree to revisions for the sake of aesthetic appearance. If there was any interest in doing so and if it was delivered at an early stage of the newbuilding process.

<p>The main contribution of this thesis is on the study of optimization methods in aft hull design. The optimization methods are inverse geometry design methods to find an aft hull with the flow velocities we specify. The analytic foundation for the flow is given by Stratford in [31], and gives a prescribed velocity distribution on the aft body. With the parameter β we have adjusted this flow to have a certain margin to separation along the pressure recovery region.</p><p>This principle and optimization method are successfully applied to design of ships with pram-type aft hull. The 2D optimized profiles corresponds to centerline buttock, and 3D hull sections are extended from this centerline buttock with a bilge radius. </p><p>Stratfords original pressure distribution for pressure recovery region were meant for Reynolds numbers up to 107. We have extended Stratfords formula to yield for ship full scale Reynolds numbers to 109. </p><p>Different optimization methods were programmed and tested. The best routine for our optimization of aft hull with Stratford flow, was when the offset y-value were the optimization parameter to be changed. When we tried to optimize a complete 2D profile with a given pressure distribution, it worked best to use the variables in a B-spline as the optimization parameter.</p><p>Extensive windtunnel tests and towing tank tests are carried out. The tests verified the hydrodynamic properties of the hulls.</p><p>Towing tests indicates that the optimized hull lines have lower total resistance than conventional ships with the same main dimensions. Both the frictional, viscous pressure resistance and wave making resistance are significantly lower. Further we can increase cargo capacity with the same power consumption, and achieve a more favourable distribution of the displacement in the aft hull.</p><p>This study has shown us that the slant angle for the bottom of the aft hull should not excess 15º with horizontal plane due to danger of separation over the bilge, and longitudinal vortices forming. </p>

The main contribution of this thesis is on the study of optimization methods in aft hull design. The optimization methods are inverse geometry design methods to find an aft hull with the flow velocities we specify. The analytic foundation for the flow is given by Stratford in [31], and gives a prescribed velocity distribution on the aft body. With the parameter β we have adjusted this flow to have a certain margin to separation along the pressure recovery region. This principle and optimization method are successfully applied to design of ships with pram-type aft hull. The 2D optimized profiles corresponds to centerline buttock, and 3D hull sections are extended from this centerline buttock with a bilge radius. Stratfords original pressure distribution for pressure recovery region were meant for Reynolds numbers up to 107. We have extended Stratfords formula to yield for ship full scale Reynolds numbers to 109. Different optimization methods were programmed and tested. The best routine for our optimization of aft hull with Stratford flow, was when the offset y-value were the optimization parameter to be changed. When we tried to optimize a complete 2D profile with a given pressure distribution, it worked best to use the variables in a B-spline as the optimization parameter. Extensive windtunnel tests and towing tank tests are carried out. The tests verified the hydrodynamic properties of the hulls. Towing tests indicates that the optimized hull lines have lower total resistance than conventional ships with the same main dimensions. Both the frictional, viscous pressure resistance and wave making resistance are significantly lower. Further we can increase cargo capacity with the same power consumption, and achieve a more favourable distribution of the displacement in the aft hull. This study has shown us that the slant angle for the bottom of the aft hull should not excess 15º with horizontal plane due to danger of separation over the bilge, and longitudinal vortices forming.

Thesis (M.Eng.), Memorial University of Newfoundland, 2000. / Bibliography: leaves 101-105.

This thesis presents a methodology and analysis tool to explore ship system vulnerability using a simplified modeling approach during the naval ship concept design process within the Concept and Requirements Exploration (CandRE) process used at Virginia Tech. The CandRE is based on a Multi-Objective Generic Optimization (MOGO) approach that explores a design space to produce a non-dominated set of ship design solutions comparing design effectiveness, risk, and cost. The current CandRE process evaluates ship characteristics and intact system options to determine a design Overall Measure of Effectiveness (OMOE) through the calculation of Measures of Performance (MOPs). Using the CandRE ship design process and a Preliminary Arrangement and Vulnerability (PAandV) model, an Overall Measure of Vulnerability (OMOV) is calculated for each ship design using the developed process and tools described in this thesis. The OMOV is calculated by combining the Vulnerability Measure of Performance (VMOP) scores across multiple ship mission capabilities. / Master of Science

This report presents the structural reliability analysis of the hull girder ultimate strength for the ship shaped FPSO Triton. The ultimate strength of the hull girder was calculated using a component approach, where the behaviour of the hull is evaluated based on the behaviour of the single structural components. Three collapse conditions were investigated; failure initiated by plate compression, failure initiated by stiffener tension and failure initiated by stiffener compression. Only vertical bending moment has been considered and the hull girder loads are divided into stillwater and wave induced components. The two loading components have been considered independent and Ferry Borges - Castenheta load combination method has been applied to obtain load combination factors for the Full Load, Partial Load (50 % loaded) and Ballast condition. The distributions of the extreme values of the vertical wave bending moments (VWBM) were calculated, based on linear strip theory and a long-term formulation. The vertical mooring forces are small and they were considered to have an insignificant influence on the bending moment response. The reliability analysis was carried out using a SORM analysis. Annual reliability indices (ß) and probabilities of failures were calculated for hogging and sagging conditions. The calculated ß values were higher than the annual reliability indices proposed in DNV Classification Notes 30.6 for serious failures in redundant structures. This indicates that the design is safe and reliable for operation in this particular location.

No description available.