Incorporating Epistemic Uncertainties in Ship Operability Study

Ship operability diagrams are commonly defined based on the seakeeping analysis, showing which course and speed can safely be taken at the sea state to satisfy pre-defined seakeeping limiting values. Although ship operability diagrams are inherently probabilistic, because of the random nature of the...

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Main Authors: Tamara Petranović, Joško Parunov
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/8/4268
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author Tamara Petranović
Joško Parunov
author_facet Tamara Petranović
Joško Parunov
author_sort Tamara Petranović
collection DOAJ
description Ship operability diagrams are commonly defined based on the seakeeping analysis, showing which course and speed can safely be taken at the sea state to satisfy pre-defined seakeeping limiting values. Although ship operability diagrams are inherently probabilistic, because of the random nature of the environmental loads, their outcome is deterministic, showing if the seakeeping criteria are satisfied or not for a certain combination of environmental and operational parameters. In the present study, uncertainties in seakeeping predictions and limiting values, which are usually neglected, are integrated into the ship operability analysis. This results in probabilistic operability diagrams, where the seakeeping criteria are exceeded with certain probabilities. The approach is demonstrated in the example of the passenger ship on a route in the Adriatic Sea. Semi-analytical closed-form expressions are used for seakeeping analysis, while limiting values for vertical bow acceleration, pitch, slamming, roll, and propeller emergence are analyzed. The second-order reliability method is used to calculate probabilities of the exceedance of the seakeeping criteria, and the results are presented as probabilistic operability diagrams. The method enables the determination of a new probabilistic operability index applicable to the ship design and represents a prerequisite for risk-based decision making in ship operation. It is also presented how the method can be validated for the existing shipping route using numerical wave databases.
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spelling doaj-art-1905e4da6fb3495d90207f1fdc7163602025-08-20T02:17:19ZengMDPI AGApplied Sciences2076-34172025-04-01158426810.3390/app15084268Incorporating Epistemic Uncertainties in Ship Operability StudyTamara Petranović0Joško Parunov1Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, CroatiaFaculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, CroatiaShip operability diagrams are commonly defined based on the seakeeping analysis, showing which course and speed can safely be taken at the sea state to satisfy pre-defined seakeeping limiting values. Although ship operability diagrams are inherently probabilistic, because of the random nature of the environmental loads, their outcome is deterministic, showing if the seakeeping criteria are satisfied or not for a certain combination of environmental and operational parameters. In the present study, uncertainties in seakeeping predictions and limiting values, which are usually neglected, are integrated into the ship operability analysis. This results in probabilistic operability diagrams, where the seakeeping criteria are exceeded with certain probabilities. The approach is demonstrated in the example of the passenger ship on a route in the Adriatic Sea. Semi-analytical closed-form expressions are used for seakeeping analysis, while limiting values for vertical bow acceleration, pitch, slamming, roll, and propeller emergence are analyzed. The second-order reliability method is used to calculate probabilities of the exceedance of the seakeeping criteria, and the results are presented as probabilistic operability diagrams. The method enables the determination of a new probabilistic operability index applicable to the ship design and represents a prerequisite for risk-based decision making in ship operation. It is also presented how the method can be validated for the existing shipping route using numerical wave databases.https://www.mdpi.com/2076-3417/15/8/4268seakeeping analysisoperability criteriauncertainties
spellingShingle Tamara Petranović
Joško Parunov
Incorporating Epistemic Uncertainties in Ship Operability Study
Applied Sciences
seakeeping analysis
operability criteria
uncertainties
title Incorporating Epistemic Uncertainties in Ship Operability Study
title_full Incorporating Epistemic Uncertainties in Ship Operability Study
title_fullStr Incorporating Epistemic Uncertainties in Ship Operability Study
title_full_unstemmed Incorporating Epistemic Uncertainties in Ship Operability Study
title_short Incorporating Epistemic Uncertainties in Ship Operability Study
title_sort incorporating epistemic uncertainties in ship operability study
topic seakeeping analysis
operability criteria
uncertainties
url https://www.mdpi.com/2076-3417/15/8/4268
work_keys_str_mv AT tamarapetranovic incorporatingepistemicuncertaintiesinshipoperabilitystudy
AT joskoparunov incorporatingepistemicuncertaintiesinshipoperabilitystudy