Pub Date : 2022-01-05DOI: 10.1080/09377255.2021.2022906
A. A. Kondratenko, Martin Bergström, M. Suominen, P. Kujala
ABSTRACT This article presents an optimization-based approach for sizing and composition of an Arctic offshore drilling support fleet considering cost-efficiency. The approach studies the main types of duties related to Arctic offshore drillings: supply, towing, anchor handling, standby, oil spill response, firefighting, and ice management. The approach considers the combined effect of the expected costs of accidental events, the versatility of individual support vessels, and ice management. The approach applies an Artificial Bee Colony algorithm-based optimization procedure. As demonstrated through case studies, the approach may help to find a range of cost-efficient fleet compositions. Some of the obtained solutions are similar to corresponding real-life fleets, indicating that the approach works in principle. Sensitivity analyses indicate that the consideration of the expected costs from accidental events significantly impacts the obtained solution, and that investments to reduce these costs may improve the overall cost-efficiency of an Arctic offshore drilling support fleet.
{"title":"An Artificial Bee Colony optimization-based approach for sizing and composition of Arctic offshore drilling support fleets considering cost-efficiency","authors":"A. A. Kondratenko, Martin Bergström, M. Suominen, P. Kujala","doi":"10.1080/09377255.2021.2022906","DOIUrl":"https://doi.org/10.1080/09377255.2021.2022906","url":null,"abstract":"ABSTRACT This article presents an optimization-based approach for sizing and composition of an Arctic offshore drilling support fleet considering cost-efficiency. The approach studies the main types of duties related to Arctic offshore drillings: supply, towing, anchor handling, standby, oil spill response, firefighting, and ice management. The approach considers the combined effect of the expected costs of accidental events, the versatility of individual support vessels, and ice management. The approach applies an Artificial Bee Colony algorithm-based optimization procedure. As demonstrated through case studies, the approach may help to find a range of cost-efficient fleet compositions. Some of the obtained solutions are similar to corresponding real-life fleets, indicating that the approach works in principle. Sensitivity analyses indicate that the consideration of the expected costs from accidental events significantly impacts the obtained solution, and that investments to reduce these costs may improve the overall cost-efficiency of an Arctic offshore drilling support fleet.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46837569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-02DOI: 10.1080/09377255.2021.2020949
P. Gualeni, Fabio Perrera, Mattia Raimondo, T. Vairo
ABSTRACT When dealing with maintenance in the ship's engine room, the space available around machinery and systems plays an important role. A proper clearance is usually indicated by the system supplier to perform maintenance operations. This space depends on the items dimensions, the kind of intervention and on the human operator, to avoid uncomfortable or dangerous positions. However sometimes the limited space in the engine rooms (as in warships, passenger ships, research vessels) implies critical issues in complying with such ideal clearances. This work aims to develop a tool to define a relation between the maintenance costs increase and the clearance reduction, regarding a single item and/or for the whole system. This tool improves the decision-making process during the design of engine room’s layout, enabling the comparison among different solutions in terms of operational costs. The approach relies on data-driven models and Bayesian inference. The predictive tool, inserted on the Systems Engineering methodology, has been tested on a real case.
{"title":"Accessibility for maintenance in the engine room: development and application of a prediction tool for operational costs estimation","authors":"P. Gualeni, Fabio Perrera, Mattia Raimondo, T. Vairo","doi":"10.1080/09377255.2021.2020949","DOIUrl":"https://doi.org/10.1080/09377255.2021.2020949","url":null,"abstract":"ABSTRACT When dealing with maintenance in the ship's engine room, the space available around machinery and systems plays an important role. A proper clearance is usually indicated by the system supplier to perform maintenance operations. This space depends on the items dimensions, the kind of intervention and on the human operator, to avoid uncomfortable or dangerous positions. However sometimes the limited space in the engine rooms (as in warships, passenger ships, research vessels) implies critical issues in complying with such ideal clearances. This work aims to develop a tool to define a relation between the maintenance costs increase and the clearance reduction, regarding a single item and/or for the whole system. This tool improves the decision-making process during the design of engine room’s layout, enabling the comparison among different solutions in terms of operational costs. The approach relies on data-driven models and Bayesian inference. The predictive tool, inserted on the Systems Engineering methodology, has been tested on a real case.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44528090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-14DOI: 10.1080/09377255.2021.1990466
D. Konispoliatis, S. Mavrakos
ABSTRACT The paper deals with the analytical evaluation of the linearized exciting wave forces; hydrodynamic coefficients and wave drift forces acting on a free-floating vertical cylindrical body placed in front of a reflecting orthogonal vertical wall. Linear potential theory is assumed, and the associated diffraction and radiation problems are solved in the frequency domain. The hydrodynamic interactions among the body and the adjacent breakwater are taken into account by applying a theoretical model based on the method of images, considering the breakwater as a fully reflecting, bottom mounted and water surface piercing wall of infinite length. The theoretical approach is supplemented by a numerical model considering the orthogonal breakwater as a barrier of finite length. The results of both formulations are compared with the ones corresponding to an isolated cylindrical body demonstrating the amplified scattered and reflected waves at specific frequency ranges originating from the presence of the orthogonal breakwater.
{"title":"Hydrodynamics of a free-floating cylinder in front of an orthogonal vertical wall","authors":"D. Konispoliatis, S. Mavrakos","doi":"10.1080/09377255.2021.1990466","DOIUrl":"https://doi.org/10.1080/09377255.2021.1990466","url":null,"abstract":"ABSTRACT The paper deals with the analytical evaluation of the linearized exciting wave forces; hydrodynamic coefficients and wave drift forces acting on a free-floating vertical cylindrical body placed in front of a reflecting orthogonal vertical wall. Linear potential theory is assumed, and the associated diffraction and radiation problems are solved in the frequency domain. The hydrodynamic interactions among the body and the adjacent breakwater are taken into account by applying a theoretical model based on the method of images, considering the breakwater as a fully reflecting, bottom mounted and water surface piercing wall of infinite length. The theoretical approach is supplemented by a numerical model considering the orthogonal breakwater as a barrier of finite length. The results of both formulations are compared with the ones corresponding to an isolated cylindrical body demonstrating the amplified scattered and reflected waves at specific frequency ranges originating from the presence of the orthogonal breakwater.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43438070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-08DOI: 10.1080/09377255.2021.1966575
L. Birk
ABSTRACT In a series of landmark reports and papers, J.L. Hess and A.M.O. Smith of Douglas Aircraft Company, Inc. introduced the quadrilateral constant source panel to solve three-dimensional nonlifting potential flow problems. Later a panel with constant dipole (doublet) distribution was added for lifting flow computations. Hess and Smith's publications provide equations for the computation of the velocities induced by the singularity distributions along with required geometric properties of the panel. Equations are presented considering an implementation in Fortran (Versions II and IV), the commonly used programming language for numerical methods at the time. The present paper builds on Hess and Smith's groundbreaking work, restating equations with modern programming languages in mind capable of fast vector operations like Fortran 95, Python or Julia. Formulas are provided for the computation of geometric properties, coordinate transformations, as well as first and second-order potential derivatives. Example input and output data allow readers to test and validate their own implementation.
{"title":"A comprehensive and practical guide to the Hess and Smith constant source and dipole panel","authors":"L. Birk","doi":"10.1080/09377255.2021.1966575","DOIUrl":"https://doi.org/10.1080/09377255.2021.1966575","url":null,"abstract":"ABSTRACT In a series of landmark reports and papers, J.L. Hess and A.M.O. Smith of Douglas Aircraft Company, Inc. introduced the quadrilateral constant source panel to solve three-dimensional nonlifting potential flow problems. Later a panel with constant dipole (doublet) distribution was added for lifting flow computations. Hess and Smith's publications provide equations for the computation of the velocities induced by the singularity distributions along with required geometric properties of the panel. Equations are presented considering an implementation in Fortran (Versions II and IV), the commonly used programming language for numerical methods at the time. The present paper builds on Hess and Smith's groundbreaking work, restating equations with modern programming languages in mind capable of fast vector operations like Fortran 95, Python or Julia. Formulas are provided for the computation of geometric properties, coordinate transformations, as well as first and second-order potential derivatives. Example input and output data allow readers to test and validate their own implementation.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43023749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-05DOI: 10.1080/09377255.2021.1973263
Himabindu Allaka, Morel Groper
ABSTRACT High-speed planing craft operating in real seaways encounter high impact loads. The extreme motions and accelerations resulting from such impacts adversely affect the structure of the craft and its payload as well as pose a risk to the crew on-board. Limiting craft speed according to the sea state using a speed-wave height operational envelope might ensure structural integrity and greatly improve safe navigation. Accurate estimation of motion and acceleration of planing craft in a seaway is a key requirement in developing reliable and usable allowable speed vs. wave height operational curves. In this paper, the Motion Assessment of Planing Craft in a Seaway (MAPCS) tool, a nonlinear time-domain approach vs. several existing approaches based on experimental, empirical and classification societies’ formulas for vertical accelerations and speed vs. wave height limit curves are compared. It is found that the MAPCS approach provides more realistic estimations compared to the commonly employed methods.
{"title":"Speed–wave height operational envelope for high-speed planing craft in seaways: theoretical vs. empirical methods","authors":"Himabindu Allaka, Morel Groper","doi":"10.1080/09377255.2021.1973263","DOIUrl":"https://doi.org/10.1080/09377255.2021.1973263","url":null,"abstract":"ABSTRACT High-speed planing craft operating in real seaways encounter high impact loads. The extreme motions and accelerations resulting from such impacts adversely affect the structure of the craft and its payload as well as pose a risk to the crew on-board. Limiting craft speed according to the sea state using a speed-wave height operational envelope might ensure structural integrity and greatly improve safe navigation. Accurate estimation of motion and acceleration of planing craft in a seaway is a key requirement in developing reliable and usable allowable speed vs. wave height operational curves. In this paper, the Motion Assessment of Planing Craft in a Seaway (MAPCS) tool, a nonlinear time-domain approach vs. several existing approaches based on experimental, empirical and classification societies’ formulas for vertical accelerations and speed vs. wave height limit curves are compared. It is found that the MAPCS approach provides more realistic estimations compared to the commonly employed methods.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42294435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-05DOI: 10.1080/09377255.2021.1973264
I. Gypa, Marcus Jansson, Krister Wolff, R. Bensow
ABSTRACT Marine propeller design can be carried out with the aid of automated optimization, but experience shows that a such an approach has still been inferior to manual design in industrial scenarios. In this study, the automated propeller design optimization is evolved by integrating human–computer interaction as an intermediate step. An interactive optimization methodology, based on interactive genetic algorithms (IGAs), has been developed, where the blade designers systematically guide a genetic algorithm towards the objectives. The designers visualize and assess the shape of the blade cavitation and this evaluation is integrated in the optimization method. The IGA is further integrated with a support-vector machine model, in order to avoid user fatigue, IGA's main disadvantage. The results of the present study show that the IGA optimization searches solutions in a more targeted manner and eventually finds more non-dominated feasible designs that also show a good cavitation behaviour in agreement with designer preference.
{"title":"Propeller optimization by interactive genetic algorithms and machine learning","authors":"I. Gypa, Marcus Jansson, Krister Wolff, R. Bensow","doi":"10.1080/09377255.2021.1973264","DOIUrl":"https://doi.org/10.1080/09377255.2021.1973264","url":null,"abstract":"ABSTRACT Marine propeller design can be carried out with the aid of automated optimization, but experience shows that a such an approach has still been inferior to manual design in industrial scenarios. In this study, the automated propeller design optimization is evolved by integrating human–computer interaction as an intermediate step. An interactive optimization methodology, based on interactive genetic algorithms (IGAs), has been developed, where the blade designers systematically guide a genetic algorithm towards the objectives. The designers visualize and assess the shape of the blade cavitation and this evaluation is integrated in the optimization method. The IGA is further integrated with a support-vector machine model, in order to avoid user fatigue, IGA's main disadvantage. The results of the present study show that the IGA optimization searches solutions in a more targeted manner and eventually finds more non-dominated feasible designs that also show a good cavitation behaviour in agreement with designer preference.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46390430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-03DOI: 10.1080/09377255.2021.1962680
A. Papanikolaou
It is my pleasure to present you a review of the recently published book of Springer Nature on ‘Numerical Methods for Seakeeping Problems’. The three co-authors of the book are internationally renowned experts in the development of numerical methods/software tools and their use in solving practical problems of seakeeping of ships and floating structures. The material of the book is to a large extent based on lectures held at the Technical University Hamburg-Harburg and the University of Duisburg-Essen, as well as on cited publications of the authors. Even more, all three authors have many years of experience with the service work of a major classification society (Germanischer Lloyd), when they supported the needs of the international maritime industry. Whereas in the past the knowledge of ship’s seakeeping was considered of prime importance only for special types of ships (e.g. naval ships), when compared to ship’s calm water performance and stability, it is not so nowadays in view of enhanced requirements for ship’s operation in realistic sea conditions and the safety of ships, of people onboard and cargo related to ship’s dynamic (intact and damage) stability. Even more, the recently introduced international regulations for the reduction of Green House Gas emissions, affecting both ship’s design and operation, call for methods and tools to assess ship’s performance in realistic sea conditions. The gained knowledge from the longstanding development of efficient numerical methods and software tools, along with their practical use, are presented in this book by a renowned team of experts and will be briefly commented in the following. The book consists of 17 chapters. After a brief introduction into the subject of the book in chapter 1, while considering marine accidents that were affected by adverse weather conditions, the theory of seakeeping is gradually introduced by first presenting the governing fundamental equations of fluid flow (incompressible viscous and ideal fluids) and the rigid body motions (nonlinear and linearized equations of motion) in chapter 2. In chapter 3, fundamental numerical methods for the incompressible potential flows (with and without lift) are presented, along with a demonstration software tool for the two-dimensional flow around a smooth body without lift. In chapter 4 the basic theory of regular and irregular water waves is introduced, while considering the linear superposition principle and spectral analysis techniques for the simulation of linear and nonlinear natural seaways and their ensuing statistics of important parameters. In chapter 5, quasi two-dimensional strip theory seakeeping methods are elaborated, starting with a brief history of developments after the fundamental work of F. Ursell in 1949. Strip theory methods became very popular over the years due to their low computational effort and the wide dissemination of the ensuing theory and numerical implementation. The linear and nonlinear computation of
{"title":"Numerical methods for seakeeping problems","authors":"A. Papanikolaou","doi":"10.1080/09377255.2021.1962680","DOIUrl":"https://doi.org/10.1080/09377255.2021.1962680","url":null,"abstract":"It is my pleasure to present you a review of the recently published book of Springer Nature on ‘Numerical Methods for Seakeeping Problems’. The three co-authors of the book are internationally renowned experts in the development of numerical methods/software tools and their use in solving practical problems of seakeeping of ships and floating structures. The material of the book is to a large extent based on lectures held at the Technical University Hamburg-Harburg and the University of Duisburg-Essen, as well as on cited publications of the authors. Even more, all three authors have many years of experience with the service work of a major classification society (Germanischer Lloyd), when they supported the needs of the international maritime industry. Whereas in the past the knowledge of ship’s seakeeping was considered of prime importance only for special types of ships (e.g. naval ships), when compared to ship’s calm water performance and stability, it is not so nowadays in view of enhanced requirements for ship’s operation in realistic sea conditions and the safety of ships, of people onboard and cargo related to ship’s dynamic (intact and damage) stability. Even more, the recently introduced international regulations for the reduction of Green House Gas emissions, affecting both ship’s design and operation, call for methods and tools to assess ship’s performance in realistic sea conditions. The gained knowledge from the longstanding development of efficient numerical methods and software tools, along with their practical use, are presented in this book by a renowned team of experts and will be briefly commented in the following. The book consists of 17 chapters. After a brief introduction into the subject of the book in chapter 1, while considering marine accidents that were affected by adverse weather conditions, the theory of seakeeping is gradually introduced by first presenting the governing fundamental equations of fluid flow (incompressible viscous and ideal fluids) and the rigid body motions (nonlinear and linearized equations of motion) in chapter 2. In chapter 3, fundamental numerical methods for the incompressible potential flows (with and without lift) are presented, along with a demonstration software tool for the two-dimensional flow around a smooth body without lift. In chapter 4 the basic theory of regular and irregular water waves is introduced, while considering the linear superposition principle and spectral analysis techniques for the simulation of linear and nonlinear natural seaways and their ensuing statistics of important parameters. In chapter 5, quasi two-dimensional strip theory seakeeping methods are elaborated, starting with a brief history of developments after the fundamental work of F. Ursell in 1949. Strip theory methods became very popular over the years due to their low computational effort and the wide dissemination of the ensuing theory and numerical implementation. The linear and nonlinear computation of","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1962680","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46780497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-20DOI: 10.1080/09377255.2021.1954835
H. Yasukawa, N. Hirata, Y. Nakayama, A. Matsuda
ABSTRACT The drift characteristics in wind of a dead ship that cannot sail on its own are investigated experimentally and theoretically. First, a free-drift test of a bulk carrier model in wind is conducted. Next, a time-domain simulation method is developed for predicting the drift motion of the dead ship in wind. Tank tests and motion simulations show that the dead ship drifts with a large hull drift angle over in wind, and the converged drift angle is independent of wind speed and initial ship heading angle. To explain why the dead ship drifts with a large drift angle in wind, a theoretical formula is derived for investigating the motion stability of the dead ship in wind. It is theoretically confirmed that the ship drifts stably with a large drift angle over in wind, whereas drift angles of and result in unstable motion. Thus the reason for the drift behaviour of the dead ship is clarified.
{"title":"Drifting of a dead ship in wind","authors":"H. Yasukawa, N. Hirata, Y. Nakayama, A. Matsuda","doi":"10.1080/09377255.2021.1954835","DOIUrl":"https://doi.org/10.1080/09377255.2021.1954835","url":null,"abstract":"ABSTRACT The drift characteristics in wind of a dead ship that cannot sail on its own are investigated experimentally and theoretically. First, a free-drift test of a bulk carrier model in wind is conducted. Next, a time-domain simulation method is developed for predicting the drift motion of the dead ship in wind. Tank tests and motion simulations show that the dead ship drifts with a large hull drift angle over in wind, and the converged drift angle is independent of wind speed and initial ship heading angle. To explain why the dead ship drifts with a large drift angle in wind, a theoretical formula is derived for investigating the motion stability of the dead ship in wind. It is theoretically confirmed that the ship drifts stably with a large drift angle over in wind, whereas drift angles of and result in unstable motion. Thus the reason for the drift behaviour of the dead ship is clarified.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1954835","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42036406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-06DOI: 10.1080/09377255.2021.1947666
M. Aguiari, M. Gaiotti, C. Rizzo
ABSTRACT Hull weight is a design parameter affecting the whole performances of a ship, being related to building costs, operational costs, maintenance and durability, and not least to satisfaction of functional requirements. Naval ships are no exception and impact of hull weight is crucial to fulfil mission requirements. In the light of the above, weight reduction is one of the main design drivers and it should be duly accounted for since the concept design phase. In this paper, a design approach intended for pre-contractual design phases is presented. It takes advantage of recent developments and trends of construction rules as well as of nowadays-available computation potential to update and improve the traditional scantling design approach, applied since decades by designers. The complexity and computational burden is kept to a minimum to provide a user-friendly procedure applicable in everyday working practice. Designers’ experience and judgment continue to drive the whole process. A Visual Basic support software has been developed with worksheet interfaces to implement the proposed scantling design procedure. Test cases showed significant weight reductions with respect to as-built ships and to scantling obtained by applying traditional design procedures.
{"title":"A design approach to reduce hull weight of naval ships","authors":"M. Aguiari, M. Gaiotti, C. Rizzo","doi":"10.1080/09377255.2021.1947666","DOIUrl":"https://doi.org/10.1080/09377255.2021.1947666","url":null,"abstract":"ABSTRACT Hull weight is a design parameter affecting the whole performances of a ship, being related to building costs, operational costs, maintenance and durability, and not least to satisfaction of functional requirements. Naval ships are no exception and impact of hull weight is crucial to fulfil mission requirements. In the light of the above, weight reduction is one of the main design drivers and it should be duly accounted for since the concept design phase. In this paper, a design approach intended for pre-contractual design phases is presented. It takes advantage of recent developments and trends of construction rules as well as of nowadays-available computation potential to update and improve the traditional scantling design approach, applied since decades by designers. The complexity and computational burden is kept to a minimum to provide a user-friendly procedure applicable in everyday working practice. Designers’ experience and judgment continue to drive the whole process. A Visual Basic support software has been developed with worksheet interfaces to implement the proposed scantling design procedure. Test cases showed significant weight reductions with respect to as-built ships and to scantling obtained by applying traditional design procedures.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1947666","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46995777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.1080/09377255.2021.1934362
S. Gaggero, M. Martinelli
ABSTRACT Pre- and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (pre-swirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.
{"title":"Pre- and post-swirl fins design for improved propulsive performances","authors":"S. Gaggero, M. Martinelli","doi":"10.1080/09377255.2021.1934362","DOIUrl":"https://doi.org/10.1080/09377255.2021.1934362","url":null,"abstract":"ABSTRACT\u0000 Pre- and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (pre-swirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.","PeriodicalId":51883,"journal":{"name":"Ship Technology Research","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09377255.2021.1934362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48572134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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