Liftboat Stability Using Energy-to-Incline and Varying Inclination Direction.
Saved in:
| Title: | Liftboat Stability Using Energy-to-Incline and Varying Inclination Direction. |
|---|---|
| Authors: | Ryan, Kieran1, Tobey, Ethan2 ethan.j.tobey@uscg.mil, Burke, Daniel3, Larkin, Tara4, Taylor, Todd4, Lawrence, Andrew5, Thomas, Brian6 |
| Source: | Journal of Ship Production & Design. Feb2025, Vol. 41 Issue 1, p27-34. 8p. |
| Subjects: | Computational physics, Flags of the United States, Center of mass, Potential energy, Rotational motion |
| Abstract: | Domestic U.S. flagged liftboats have relatively low length-to-beam ratios (L/B), compared with typical vessels, and operate with minimal freeboard and high vertical centers of gravity. As such, domestic liftboats can have poor righting arm characteristics that may not be revealed by conventional regulatory stability analyses that evaluate in the pure heel direction. This study adapts a novel energy-to-incline method and varying axis stability analysis developed by Andrew Breuer for Mobile Offshore Drilling Units to low L/B liftboats. This method of generating energy-to-incline surfaces was applied to the limiting case of a low L/B = 1 liftboat and to the liftboat SEACOR POWER (L/B = 2.02) to produce energy contour plots for a range of heel and trim values and to identify capsize points. Righting arm curves were mathematically computed from these surfaces by extracting incremental energy along pathways to capsize. For the low L/B ratio vessels, this resulted in truncated righting arm curves for inclinations inmany directions, associated with the computational approach and the physics of orthogonal tipping. Analysis of the results revealed that low L/B liftboats have their lowest-energy pathways to capsize in inclination directions different fromthe traditionally assumed heel direction. As such, it is proposed that much of the U.S. domestic liftboat fleetmay also exhibit such "off axis" weakest capsize directions. Finally, standard hydrostatic stability software was used to compute righting arms for the L/B = 1 liftboatwhen inclined directly from the point of static equilibrium to a known capsize point, while fixing the angle of rotation in the direction orthogonal to the straight-line path. The resulting righting armapproximated well the lowest-energy righting arms fromthemore computationally intensive energy-to-incline method. Future research would be to assess whether such straight-line, fixed-rotation paths provide a good approximation for the minimum energy righting arms for liftboats over a range of L/B. If so, this method would provide an efficientmeans to produce liftboat righting arms with two zero-crossing points necessary for comparison with stability regulations. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Ship Production & Design is the property of Society of Naval Architects & Marine Engineers and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
|---|---|
| Header | DbId: egs DbLabel: Engineering Source An: 183631411 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
| IllustrationInfo | |
| Items | – Name: Title Label: Title Group: Ti Data: Liftboat Stability Using Energy-to-Incline and Varying Inclination Direction. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Ryan%2C+Kieran%22">Ryan, Kieran</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Tobey%2C+Ethan%22">Tobey, Ethan</searchLink><relatesTo>2</relatesTo><i> ethan.j.tobey@uscg.mil</i><br /><searchLink fieldCode="AR" term="%22Burke%2C+Daniel%22">Burke, Daniel</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Larkin%2C+Tara%22">Larkin, Tara</searchLink><relatesTo>4</relatesTo><br /><searchLink fieldCode="AR" term="%22Taylor%2C+Todd%22">Taylor, Todd</searchLink><relatesTo>4</relatesTo><br /><searchLink fieldCode="AR" term="%22Lawrence%2C+Andrew%22">Lawrence, Andrew</searchLink><relatesTo>5</relatesTo><br /><searchLink fieldCode="AR" term="%22Thomas%2C+Brian%22">Thomas, Brian</searchLink><relatesTo>6</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Ship+Production+%26+Design%22">Journal of Ship Production & Design</searchLink>. Feb2025, Vol. 41 Issue 1, p27-34. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Computational+physics%22">Computational physics</searchLink><br /><searchLink fieldCode="DE" term="%22Flags+of+the+United+States%22">Flags of the United States</searchLink><br /><searchLink fieldCode="DE" term="%22Center+of+mass%22">Center of mass</searchLink><br /><searchLink fieldCode="DE" term="%22Potential+energy%22">Potential energy</searchLink><br /><searchLink fieldCode="DE" term="%22Rotational+motion%22">Rotational motion</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Domestic U.S. flagged liftboats have relatively low length-to-beam ratios (L/B), compared with typical vessels, and operate with minimal freeboard and high vertical centers of gravity. As such, domestic liftboats can have poor righting arm characteristics that may not be revealed by conventional regulatory stability analyses that evaluate in the pure heel direction. This study adapts a novel energy-to-incline method and varying axis stability analysis developed by Andrew Breuer for Mobile Offshore Drilling Units to low L/B liftboats. This method of generating energy-to-incline surfaces was applied to the limiting case of a low L/B = 1 liftboat and to the liftboat SEACOR POWER (L/B = 2.02) to produce energy contour plots for a range of heel and trim values and to identify capsize points. Righting arm curves were mathematically computed from these surfaces by extracting incremental energy along pathways to capsize. For the low L/B ratio vessels, this resulted in truncated righting arm curves for inclinations inmany directions, associated with the computational approach and the physics of orthogonal tipping. Analysis of the results revealed that low L/B liftboats have their lowest-energy pathways to capsize in inclination directions different fromthe traditionally assumed heel direction. As such, it is proposed that much of the U.S. domestic liftboat fleetmay also exhibit such "off axis" weakest capsize directions. Finally, standard hydrostatic stability software was used to compute righting arms for the L/B = 1 liftboatwhen inclined directly from the point of static equilibrium to a known capsize point, while fixing the angle of rotation in the direction orthogonal to the straight-line path. The resulting righting armapproximated well the lowest-energy righting arms fromthemore computationally intensive energy-to-incline method. Future research would be to assess whether such straight-line, fixed-rotation paths provide a good approximation for the minimum energy righting arms for liftboats over a range of L/B. If so, this method would provide an efficientmeans to produce liftboat righting arms with two zero-crossing points necessary for comparison with stability regulations. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Ship Production & Design is the property of Society of Naval Architects & Marine Engineers and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=183631411 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.5957/JSPD.04240012 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 27 Subjects: – SubjectFull: Computational physics Type: general – SubjectFull: Flags of the United States Type: general – SubjectFull: Center of mass Type: general – SubjectFull: Potential energy Type: general – SubjectFull: Rotational motion Type: general Titles: – TitleFull: Liftboat Stability Using Energy-to-Incline and Varying Inclination Direction. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Ryan, Kieran – PersonEntity: Name: NameFull: Tobey, Ethan – PersonEntity: Name: NameFull: Burke, Daniel – PersonEntity: Name: NameFull: Larkin, Tara – PersonEntity: Name: NameFull: Taylor, Todd – PersonEntity: Name: NameFull: Lawrence, Andrew – PersonEntity: Name: NameFull: Thomas, Brian IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 21582866 Numbering: – Type: volume Value: 41 – Type: issue Value: 1 Titles: – TitleFull: Journal of Ship Production & Design Type: main |
| ResultId | 1 |
