{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/73505"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/73505","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The Effect of Shallow Water on Roll Damping and Rolling Period","abstract":"Significant effort has been made to quantify and predict roll damping of vessels in the past. Similarly, efforts have been made to provide effective methods for calculating the roll gyradius of vessels. Both the damping and the gyradius of a vessel are traditionally quantified through the use of a sally test. Experience with the USS Midway showed that shallow water has significant effect on the rolling period and thus the experimentally determined roll gyradius. To date, little effort has been directed to the problem of the effect of shallow water on roll damping and roll period except when trying to match model and full scale experimental data. No clear guidelines exist for the boundary between deep and shallow water or the amount of overprediction of roll period that is likely for a given water depth. In order to provide greater understanding of the effects of shallow water on roll period and roll damping, this thesis performed experiments in varying scale water depths for 5 models: 4 box barges and a model of the USS Essex. The following conclusions were reached: As water depth to draft ratio, d/T, approaches 1 the roll period can increase as much as 14%. The boundary between deep and shallow water is a water depth somewhere between 4 and 7 times the vessel draft depending on the particulars of the vessel's hull form. Vessels with a larger beam to draft ratio will experience shallow water effects in relatively deeper water, that is to say the depth to draft ratio will be greater at the upper limit of deep water. Additionally, vessels with a higher beam to draft ratio will experience larger shallow water effects for a given depth to draft ratio. Finally, for vessels of very fine hull forms, the boundary between deep and shallow water will occur a relatively shallower depths, in other terms, the boundary will occur at a lower depth to draft ratio.","abstract_html":"Significant effort has been made to quantify and predict roll damping of vessels in the past. Similarly, efforts have been made to provide effective methods for calculating the roll gyradius of vessels. Both the damping and the gyradius of a vessel are traditionally quantified through the use of a sally test. Experience with the USS Midway showed that shallow water has significant effect on the rolling period and thus the experimentally determined roll gyradius. To date, little effort has been directed to the problem of the effect of shallow water on roll damping and roll period except when trying to match model and full scale experimental data. No clear guidelines exist for the boundary between deep and shallow water or the amount of overprediction of roll period that is likely for a given water depth. In order to provide greater understanding of the effects of shallow water on roll period and roll damping, this thesis performed experiments in varying scale water depths for 5 models: 4 box barges and a model of the USS Essex. The following conclusions were reached: As water depth to draft ratio, d/T, approaches 1 the roll period can increase as much as 14%. The boundary between deep and shallow water is a water depth somewhere between 4 and 7 times the vessel draft depending on the particulars of the vessel's hull form. Vessels with a larger beam to draft ratio will experience shallow water effects in relatively deeper water, that is to say the depth to draft ratio will be greater at the upper limit of deep water. Additionally, vessels with a higher beam to draft ratio will experience larger shallow water effects for a given depth to draft ratio. Finally, for vessels of very fine hull forms, the boundary between deep and shallow water will occur a relatively shallower depths, in other terms, the boundary will occur at a lower depth to draft ratio.","abstract_has_math":false,"creators":["Hansch, David Laurence"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Ocean Engineering","degree_department":"Aerospace and Ocean Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["McCue-Weil, Leigh S."],"committee_members":["Brown, Alan J.","Hajj, Muhammad R."],"year":2015,"date_issued":"2015-06-04","date_published":"2015-06-04","updated_at":"2026-07-22T22:20:38Z","subjects":["Roll Damping","Roll Period","Shallow Water"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:5315"],"render_values":[{"text":"vt_gsexam:5315","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/73505","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":["Brown, Alan J.","Hajj, Muhammad R."]},{"key":"dc:contributor.department","label":"Department","values":["Aerospace and Ocean Engineering"]},{"key":"dc:creator","label":"Author","values":["Hansch, David Laurence"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-11-26T07:00:22Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-11-26T07:00:22Z"]},{"key":"dc:date.issued","label":"Date","values":["2015-06-04"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["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":["Roll Damping","Roll Period","Shallow Water"]}]},{"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":["vt_gsexam:5315"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/73505"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Significant effort has been made to quantify and predict roll damping of vessels in the past. Similarly, efforts have been made to provide effective methods for calculating the roll gyradius of vessels. Both the damping and the gyradius of a vessel are traditionally quantified through the use of a sally test. Experience with the USS Midway showed that shallow water has significant effect on the rolling period and thus the experimentally determined roll gyradius. To date, little effort has been directed to the problem of the effect of shallow water on roll damping and roll period except when trying to match model and full scale experimental data. No clear guidelines exist for the boundary between deep and shallow water or the amount of overprediction of roll period that is likely for a given water depth. In order to provide greater understanding of the effects of shallow water on roll period and roll damping, this thesis performed experiments in varying scale water depths for 5 models: 4 box barges and a model of the USS Essex. The following conclusions were reached: As water depth to draft ratio, d/T, approaches 1 the roll period can increase as much as 14%. The boundary between deep and shallow water is a water depth somewhere between 4 and 7 times the vessel draft depending on the particulars of the vessel's hull form. Vessels with a larger beam to draft ratio will experience shallow water effects in relatively deeper water, that is to say the depth to draft ratio will be greater at the upper limit of deep water. Additionally, vessels with a higher beam to draft ratio will experience larger shallow water effects for a given depth to draft ratio. Finally, for vessels of very fine hull forms, the boundary between deep and shallow water will occur a relatively shallower depths, in other terms, the boundary will occur at a lower depth to draft ratio."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["The Effect of Shallow Water on Roll Damping and Rolling Period"]}]}],"canonical_facts":{"dc:contributor.committeechair":["McCue-Weil, Leigh S."],"dc:contributor.committeemember":["Brown, Alan J.","Hajj, Muhammad R."],"dc:contributor.department":["Aerospace and Ocean Engineering"],"dc:creator":["Hansch, David Laurence"],"dc:date.accessioned":["2016-11-26T07:00:22Z"],"dc:date.available":["2016-11-26T07:00:22Z"],"dc:date.issued":["2015-06-04"],"dc:description.abstract":["Significant effort has been made to quantify and predict roll damping of vessels in the past. Similarly, efforts have been made to provide effective methods for calculating the roll gyradius of vessels. Both the damping and the gyradius of a vessel are traditionally quantified through the use of a sally test. Experience with the USS Midway showed that shallow water has significant effect on the rolling period and thus the experimentally determined roll gyradius. To date, little effort has been directed to the problem of the effect of shallow water on roll damping and roll period except when trying to match model and full scale experimental data. No clear guidelines exist for the boundary between deep and shallow water or the amount of overprediction of roll period that is likely for a given water depth. In order to provide greater understanding of the effects of shallow water on roll period and roll damping, this thesis performed experiments in varying scale water depths for 5 models: 4 box barges and a model of the USS Essex. The following conclusions were reached: As water depth to draft ratio, d/T, approaches 1 the roll period can increase as much as 14%. The boundary between deep and shallow water is a water depth somewhere between 4 and 7 times the vessel draft depending on the particulars of the vessel's hull form. Vessels with a larger beam to draft ratio will experience shallow water effects in relatively deeper water, that is to say the depth to draft ratio will be greater at the upper limit of deep water. Additionally, vessels with a higher beam to draft ratio will experience larger shallow water effects for a given depth to draft ratio. Finally, for vessels of very fine hull forms, the boundary between deep and shallow water will occur a relatively shallower depths, in other terms, the boundary will occur at a lower depth to draft ratio."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:5315"],"dc:identifier.uri":["http://hdl.handle.net/10919/73505"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Roll Damping","Roll Period","Shallow Water"],"dc:title":["The Effect of Shallow Water on Roll Damping and Rolling Period"],"dc:type":["Thesis"],"thesis:degree_discipline":["Ocean Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:38Z"}