{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/32322"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/32322","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Full Scale Investigation of Bilge Keel Effectiveness at Forward Speed","abstract":"Ship motions in a seaway have long been of great importance, and today with advanced hull forms and higher speeds they are as important as ever. While one can now often adequately predict heave, pitch, sway, yaw and even surge, roll motions are much more difficult. Roll is the one motion that is very dependent upon viscous effects of the fluid. Recently, at David Taylor Model Basin, there have been model experiments where the bilge keels were instrumented in order to directly measure their damping force upon the vessel. To build upon this work and to validate it when applied to full scale vessels, a trial using the Italian naval vessel Nave Bettica was performed. The objective of this thesis is to describe the experiment, present and analyze the results, and offer some conclusions based upon these results. The process of instrumenting the port bilge keel using strain gages and correlating their output to pressures and total forces is described. Selected results for different forward speeds are presented, with full results in the appendices. Particle image velocimetry (PIV) was also performed during the test and was used to measure the flow field in a three foot by three foot area under the aft end of the same bilge keel. Selected image series are presented, as is a methodology for using these images to calculate the center of pressure and the corresponding results.","abstract_html":"Ship motions in a seaway have long been of great importance, and today with advanced hull forms and higher speeds they are as important as ever. While one can now often adequately predict heave, pitch, sway, yaw and even surge, roll motions are much more difficult. Roll is the one motion that is very dependent upon viscous effects of the fluid. Recently, at David Taylor Model Basin, there have been model experiments where the bilge keels were instrumented in order to directly measure their damping force upon the vessel. To build upon this work and to validate it when applied to full scale vessels, a trial using the Italian naval vessel Nave Bettica was performed. The objective of this thesis is to describe the experiment, present and analyze the results, and offer some conclusions based upon these results. The process of instrumenting the port bilge keel using strain gages and correlating their output to pressures and total forces is described. Selected results for different forward speeds are presented, with full results in the appendices. Particle image velocimetry (PIV) was also performed during the test and was used to measure the flow field in a three foot by three foot area under the aft end of the same bilge keel. Selected image series are presented, as is a methodology for using these images to calculate the center of pressure and the corresponding results.","abstract_has_math":false,"creators":["Grant, David J."],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Aerospace and Ocean Engineering","degree_department":"Aerospace and Ocean Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["McCue-Weil, Leigh S."],"committee_members":["Etebari, Ali","Hughes, Owen F."],"year":2008,"date_issued":"2008-04-28","date_published":"2008-04-28","updated_at":"2026-07-22T22:20:26Z","subjects":["bilge keel","roll damping","full scale"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05072008-133744"],"render_values":[{"text":"etd-05072008-133744","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/32322","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["McCue-Weil, Leigh S."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Etebari, Ali","Hughes, Owen F."]},{"key":"dc:contributor.department","label":"Department","values":["Aerospace and Ocean Engineering"]},{"key":"dc:creator","label":"Author","values":["Grant, David J."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:35:31Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:35:31Z","2008-06-03"]},{"key":"dc:date.issued","label":"Date","values":["2008-04-28"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace and Ocean Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["bilge keel","roll damping","full scale"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05072008-133744"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/32322"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Ship motions in a seaway have long been of great importance, and today with advanced hull forms and higher speeds they are as important as ever. While one can now often adequately predict heave, pitch, sway, yaw and even surge, roll motions are much more difficult. Roll is the one motion that is very dependent upon viscous effects of the fluid. Recently, at David Taylor Model Basin, there have been model experiments where the bilge keels were instrumented in order to directly measure their damping force upon the vessel. To build upon this work and to validate it when applied to full scale vessels, a trial using the Italian naval vessel Nave Bettica was performed. The objective of this thesis is to describe the experiment, present and analyze the results, and offer some conclusions based upon these results. The process of instrumenting the port bilge keel using strain gages and correlating their output to pressures and total forces is described. Selected results for different forward speeds are presented, with full results in the appendices. Particle image velocimetry (PIV) was also performed during the test and was used to measure the flow field in a three foot by three foot area under the aft end of the same bilge keel. Selected image series are presented, as is a methodology for using these images to calculate the center of pressure and the corresponding results."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Full Scale Investigation of Bilge Keel Effectiveness at Forward Speed"]}]}],"canonical_facts":{"dc:contributor.committeechair":["McCue-Weil, Leigh S."],"dc:contributor.committeemember":["Etebari, Ali","Hughes, Owen F."],"dc:contributor.department":["Aerospace and Ocean Engineering"],"dc:creator":["Grant, David J."],"dc:date.accessioned":["2014-03-14T20:35:31Z"],"dc:date.available":["2014-03-14T20:35:31Z","2008-06-03"],"dc:date.issued":["2008-04-28"],"dc:description.abstract":["Ship motions in a seaway have long been of great importance, and today with advanced hull forms and higher speeds they are as important as ever. While one can now often adequately predict heave, pitch, sway, yaw and even surge, roll motions are much more difficult. Roll is the one motion that is very dependent upon viscous effects of the fluid. Recently, at David Taylor Model Basin, there have been model experiments where the bilge keels were instrumented in order to directly measure their damping force upon the vessel. To build upon this work and to validate it when applied to full scale vessels, a trial using the Italian naval vessel Nave Bettica was performed. The objective of this thesis is to describe the experiment, present and analyze the results, and offer some conclusions based upon these results. The process of instrumenting the port bilge keel using strain gages and correlating their output to pressures and total forces is described. Selected results for different forward speeds are presented, with full results in the appendices. Particle image velocimetry (PIV) was also performed during the test and was used to measure the flow field in a three foot by three foot area under the aft end of the same bilge keel. Selected image series are presented, as is a methodology for using these images to calculate the center of pressure and the corresponding results."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-05072008-133744"],"dc:identifier.uri":["http://hdl.handle.net/10919/32322"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["bilge keel","roll damping","full scale"],"dc:title":["Full Scale Investigation of Bilge Keel Effectiveness at Forward Speed"],"dc:type":["Thesis"],"thesis:degree_discipline":["Aerospace and Ocean Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:26Z"}