Pub Date : 2019-03-28DOI: 10.3940/rina.pro.2019.08
K. Vidal, B. Mallol, C. Hirsch, L. Poppelier
The manufacturing of propellers comes with geometrical variability that lies within predefined tolerances decreed by standardized accuracy classes. Although controlled by these tolerances classes, the variation in the design might result in a degradation of the expected propeller behaviour. In a classical deterministic design optimization, engineers improve a digital model, without taking into account these variations. Hence a new type of optimization method is recommended whereby the impact of the manufacturing variability, represented by statistical moments, is minimized. This paper presents a robust non-deterministic optimization of a ducted marine propeller mounted on an inland vessel. In this test case, the statistical moments of the propeller efficiency are optimized while axial thrust is constrained and cavitation occurrence is considered. The manufacturing uncertainties are derived from the ISO geometrical tolerances S-class. Eventually, a robust optimum is compared with a deterministic optimum in order to underline the benefits of the non-deterministic design methodology.
{"title":"THE IMPORTANCE OF A NON-DETERMINISTIC DESIGN OPTIMIZATION FOR PREDICTING REAL-LIFE PROPELLER PERFORMANCES","authors":"K. Vidal, B. Mallol, C. Hirsch, L. Poppelier","doi":"10.3940/rina.pro.2019.08","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.08","url":null,"abstract":"The manufacturing of propellers comes with geometrical variability that lies within predefined tolerances decreed by standardized accuracy classes. Although controlled by these tolerances classes, the variation in the design might result in a degradation of the expected propeller behaviour.\u0000In a classical deterministic design optimization, engineers improve a digital model, without taking into account these variations. Hence a new type of optimization method is recommended whereby the impact of the manufacturing variability, represented by statistical moments, is minimized.\u0000This paper presents a robust non-deterministic optimization of a ducted marine propeller mounted on an inland vessel. In this test case, the statistical moments of the propeller efficiency are optimized while axial thrust is constrained and cavitation occurrence is considered. The manufacturing uncertainties are derived from the ISO geometrical tolerances S-class. Eventually, a robust optimum is compared with a deterministic optimum in order to underline the benefits of the non-deterministic design methodology.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115622865","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.02
E. Fay
The issues of noise and vibration related to the propulsion system of vessels shines a bright light over the present day operation of sea going vessels. Some of the principal issues coming to the front are not new and are concerned with passenger and crew comfort which has been a touchstone for a decade or more. The most recent, more ominous issue is transmission of noise from transiting vessels and how this noise affects marine mammals. The tools used to analyse and define the expected levels of vibration and noise in the design phase are becoming more and more robust. The paper describes the use of computational fluid dynamics to predict the noise and vibration generated by hydrodynamic flow over the hull and the propeller(s) of the vessel. The analysis is carried out using the program OpenFOAM comparing the operating propeller performance coefficients with the open water propeller coefficients. The paper also looks at the effects of cavitation, vessel trim and propeller loading on a 140 meter car ferry. The loading, noise and vibration data will be quantified and compared to full scale vessel data.
{"title":"FULL SCALE PREDICTION OF HYDRODYNAMIC NOISE USING COMPUTATIONAL FLUID DYNAMICS","authors":"E. Fay","doi":"10.3940/rina.pro.2019.02","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.02","url":null,"abstract":"The issues of noise and vibration related to the propulsion system of vessels shines a bright light over the present day operation of sea going vessels. Some of the principal issues coming to the front are not new and are concerned with passenger and crew comfort which has been a touchstone for a decade or more. The most recent, more ominous issue is transmission of noise from transiting vessels and how this noise affects marine mammals.\u0000\u0000The tools used to analyse and define the expected levels of vibration and noise in the design phase are becoming more and more robust. The paper describes the use of computational fluid dynamics to predict the noise and vibration generated by hydrodynamic flow over the hull and the propeller(s) of the vessel. The analysis is carried out using the program OpenFOAM comparing the operating propeller performance coefficients with the open water propeller coefficients. The paper also looks at the effects of cavitation, vessel trim and propeller loading on a 140 meter car ferry. The loading, noise and vibration data will be quantified and compared to full scale vessel data.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121641176","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.09
J. Mcbain
An electro-mechanical replacement for hydraulically-actuated controllable pitch propellers is described. The proposed mechanism applies a thread to the rotating shaft driven by the ship’s prime mover onto which a ferromagnetic nut is threadedly mated and spun by a stator-born electromagnet; the axial motion of the nut is used to manipulate the pitch of the rotatable blades. The design completely removes any mechanical coupling between the rotor and stator systems. An argument for the mechanism’s efficiency, ease of maintenance, and reduction of weight is provided in the form of reasoning by analogy for the already well studied differentiation between hydraulic and electric cylinders. Efficiency gains of 2-3 times, a doubling of mean-time-between failure, and a reduction of weight by 10% are inferred.
{"title":"AN ELECTRO-MECHANICAL CONTROLLABLE-PITCH PROPELLER","authors":"J. Mcbain","doi":"10.3940/rina.pro.2019.09","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.09","url":null,"abstract":"An electro-mechanical replacement for hydraulically-actuated controllable pitch propellers is described. The proposed mechanism applies a thread to the rotating shaft driven by the ship’s prime mover onto which a ferromagnetic nut is threadedly mated and spun by a stator-born electromagnet; the axial motion of the nut is used to manipulate the pitch of the rotatable blades. The design completely removes any mechanical coupling between the rotor and stator systems. An argument for the mechanism’s efficiency, ease of maintenance, and reduction of weight is provided in the form of reasoning by analogy for the already well studied differentiation between hydraulic and electric cylinders. Efficiency gains of 2-3 times, a doubling of mean-time-between failure, and a reduction of weight by 10% are inferred.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122902299","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.01
N. Bulten
The usage of more sophisticated design and analysis tools have become prevalent in all industries. In order to get the true value out of these numerical tools, the actual design requirements need to be defined properly and in general, this leads to the question of how to find the right balance between conflicting requirements. More feedback on the performance of a design can be obtained with usage of numerical simulations within the design evaluation phase and with digital data collection tools in the operational phase. With the implementation of CFD simulations in the design cycle, unforeseen deviations with model testing campaigns and actual full scale sea trials has reduced, and collection of actual vessel operational data, in combination with a system simulation approach generates further insight in the actual operation, which can be used to further fine-tune the design philosophy. Detailed evaluation of the results from full scale CFD simulations have revealed interesting phenomena related to the Reynolds scaling effects of ducted propellers.
{"title":"USAGE OF DIGITAL TOOLS FOR THE OPTIMUM PROPELLER DESIGN","authors":"N. Bulten","doi":"10.3940/rina.pro.2019.01","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.01","url":null,"abstract":"The usage of more sophisticated design and analysis tools have become prevalent in all industries. In order to get the true value out of these numerical tools, the actual design requirements need to be defined properly and in general, this leads to the question of how to find the right balance between conflicting requirements. More feedback on the performance of a design can be obtained with usage of numerical simulations within the design evaluation phase and with digital data collection tools in the operational phase. With the implementation of CFD simulations in the design cycle, unforeseen deviations with model testing campaigns and actual full scale sea trials has reduced, and collection of actual vessel operational data, in combination with a system simulation approach generates further insight in the actual operation, which can be used to further fine-tune the design philosophy. Detailed evaluation of the results from full scale CFD simulations have revealed interesting phenomena related to the Reynolds scaling effects of ducted propellers.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134563324","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.03
Danio Joe, Vinai Misra, R. Vijayakumar
The impact of increased Underwater Radiated Noise (URN) over the past two decades on marine mammals has resulted in the pressing requirement to reduce it. Shipping contributes immensely to the URN. Propeller noise is a major source of URN. The reduction in Propeller noise can hence significantly help in the reduction of URN. With the sole objective of improving the hydrodynamic performance of propellers ways to prevent cavitation are being developed. However, the reduction of non cavitating noise produced by the propeller would still remain a challenge. The change in the propeller geometry can modify the acoustic characteristics. In this present study, effect of modifying the tip of DTMB4119 propeller on the acoustic and hydrodynamic characteristics is presented. The change in the flow pattern at the tip due to introduction of tip rake is also discussed. The SPL has been calculated by using the two-step Ffowcs William and Hawkings (FW-H) equations from the pressure distribution at various points around the propeller. SPL at various points in the downstream and propeller disk plane are numerically predicted and discussed.
在过去的二十年中，水下辐射噪声(URN)对海洋哺乳动物的影响越来越大，因此迫切需要减少它。航运对URN做出了巨大贡献。螺旋桨噪声是URN的主要来源。因此，降低螺旋桨噪声可以显著帮助降低URN。为了提高螺旋桨的水动力性能，人们正在研究防止空化的方法。然而，减少螺旋桨产生的非空泡噪声仍然是一个挑战。改变螺旋桨的几何形状可以改变其声学特性。本文研究了DTMB4119螺旋桨叶尖的改变对其声学和水动力特性的影响。文中还讨论了尖前角的引入对叶顶流型的影响。从螺旋桨周围各点的压力分布出发，采用两步Ffowcs William and hawkins (FW-H)方程计算了声压级。对下游和桨盘平面各点声压级进行了数值预测和讨论。
{"title":"NUMERICAL STUDY OF ACOUSTIC CHARACTERISTICS OF A DTMB 4119 PROPELLER DUE TO TIP RAKE","authors":"Danio Joe, Vinai Misra, R. Vijayakumar","doi":"10.3940/rina.pro.2019.03","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.03","url":null,"abstract":"The impact of increased Underwater Radiated Noise (URN) over the past two decades on marine mammals has resulted in the pressing requirement to reduce it. Shipping contributes immensely to the URN. Propeller noise is a major source of URN. The reduction in Propeller noise can hence significantly help in the reduction of URN. With the sole objective of improving the hydrodynamic performance of propellers ways to prevent cavitation are being developed. However, the reduction of non cavitating noise produced by the propeller would still remain a challenge. The change in the propeller geometry can modify the acoustic characteristics. In this present study, effect of modifying the tip of DTMB4119 propeller on the acoustic and hydrodynamic characteristics is presented. The change in the flow pattern at the tip due to introduction of tip rake is also discussed. The SPL has been calculated by using the two-step Ffowcs William and Hawkings (FW-H) equations from the pressure distribution at various points around the propeller. SPL at various points in the downstream and propeller disk plane are numerically predicted and discussed.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116517579","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.05
S. Gaggero
RIM driven propellers represent an unconventional, but underrated, propulsive solution which hydrodynamic design is still not obvious. In the last years, most of the attention has been devoted to the efficient coupling with electric motors, since only recently the development of permanent magnets allowed for the successful embedding of the driver directly inside the surrounding duct. From the hydrodynamic point of view, however, analysis and, in particular, design strategies are not yet ripe. In the light of the development of advanced design approaches for unconventional geometries, we propose a Simulation-Based Design Optimization tool based on RANS analyses of parametrically described geometries as a part of an automatic, multi-objective optimization loop. The SBDO is used to design a RIM driven propeller with an accelerating type duct, with improved performance simultaneously in terms both of efficiency and cavitation inception at different (design and quasi-bollard pull) functioning conditions.
{"title":"RIM DRIVEN PROPELLERS: OPTIMIZATION BASED DESIGN APPROACH USING RANS CALCULATIONS","authors":"S. Gaggero","doi":"10.3940/rina.pro.2019.05","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.05","url":null,"abstract":"RIM driven propellers represent an unconventional, but underrated, propulsive solution which hydrodynamic design is still not obvious. In the last years, most of the attention has been devoted to the efficient coupling with electric motors, since only recently the development of permanent magnets allowed for the successful embedding of the driver directly inside the surrounding duct. From the hydrodynamic point of view, however, analysis and, in particular, design strategies are not yet ripe. In the light of the development of advanced design approaches for unconventional geometries, we propose a Simulation-Based Design Optimization tool based on RANS analyses of parametrically described geometries as a part of an automatic, multi-objective optimization loop. The SBDO is used to design a RIM driven propeller with an accelerating type duct, with improved performance simultaneously in terms both of efficiency and cavitation inception at different (design and quasi-bollard pull) functioning conditions.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128700519","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.07
R. Fernández, F. Pérez-Arribas
This work presents a new design methodology for modelling the blades of ship propellers using B-spline surfaces that are a standard tool in CAD and Naval Architecture software products. Propeller blades of a ship are good examples of free form surfaces, designed specifically considering several parameters that control their performance. Traditional tools for surface design in CAD such as control point manipulation, are not appropriated for blade design, and the designers prefer to work with a collection of propeller parameters that ultimately represent its surface and that possess a clear hydrodynamic meaning. This method uses common design parameters for the geometry of propellers and produces a final B-spline surface for the geometry of the blades that can be used for the visualization, calculations, and construction of the propeller. The method starts with the definition of a 3D grid of points that form the propeller blades based on the 2D definition of a series of cross-sectional profiles at several radial locations. These 3D points consider the inclination and twist of the blades are given by rake and pitch angles, quite common in the design procedures, and also different propellers parameters such as skew and blade thickness distribution. Propeller blades are very thin objects with great changes of curvature, and if standard B-spline techniques are used, they cannot be modelled well under a tolerance unless a large number of control points is used, producing very complex surfaces. The method stresses the fitting of the blade's leading edge which has great effect on the propeller behavior and geometrically has a small curvature radius in comparison with the rest of the blades. The leading edge is difficult to reproduce with standard techniques.
{"title":"PROPELLERS GEOMETRY MODELING THROUGH B-SPLINES SURFACES","authors":"R. Fernández, F. Pérez-Arribas","doi":"10.3940/rina.pro.2019.07","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.07","url":null,"abstract":"This work presents a new design methodology for modelling the blades of ship propellers using B-spline surfaces that are a standard tool in CAD and Naval Architecture software products.\u0000Propeller blades of a ship are good examples of free form surfaces, designed specifically considering several parameters that control their performance. Traditional tools for surface design in CAD such as control point manipulation, are not appropriated for blade design, and the designers prefer to work with a collection of propeller parameters that ultimately represent its surface and that possess a clear hydrodynamic meaning.\u0000This method uses common design parameters for the geometry of propellers and produces a final B-spline surface for the geometry of the blades that can be used for the visualization, calculations, and construction of the propeller.\u0000The method starts with the definition of a 3D grid of points that form the propeller blades based on the 2D definition of a series of cross-sectional profiles at several radial locations. These 3D points consider the inclination and twist of the blades are given by rake and pitch angles, quite common in the design procedures, and also different propellers parameters such as skew and blade thickness distribution.\u0000Propeller blades are very thin objects with great changes of curvature, and if standard B-spline techniques are used, they cannot be modelled well under a tolerance unless a large number of control points is used, producing very complex surfaces.\u0000The method stresses the fitting of the blade's leading edge which has great effect on the propeller behavior and geometrically has a small curvature radius in comparison with the rest of the blades. The leading edge is difficult to reproduce with standard techniques.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123113998","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 : 2019-03-28DOI: 10.3940/rina.pro.2019.04
K. Himei, K. Okazaki, H. Yamaguchi
On the off-design condition of CPP or podded propulsor, the angle of attack against the propeller blade or the flow interaction between propeller and pod housing is quite different from the propeller design condition. The flow around them is very complex. Hence there is the difficulty for numerical estimating. In order to verify the applicability to wide range of the off-design condition, RANS simulations were executed. The calculation range for CPP was complete two quadrant condition each at several pitch setting. Regarding podded propulsor, pull type and push one having the common propeller and housing were targeted and the range of pod steering angle were set to all 360 degrees. Hydrodynamic performance as these calculated results were compared with published experimental results including the rotational moment of changing CPP’s pitch angle or steering the pod housing. Then, it was found that there were good agreements except for the particular kind of the operating conditions.
{"title":"NUMERICAL ESTIMATION ABOUT PERFORMANCE OF CPP AND PODDED PROPULSOR ON MANY OFF-DESIGN CONDITIONS USING RANS APPROACH","authors":"K. Himei, K. Okazaki, H. Yamaguchi","doi":"10.3940/rina.pro.2019.04","DOIUrl":"https://doi.org/10.3940/rina.pro.2019.04","url":null,"abstract":"On the off-design condition of CPP or podded propulsor, the angle of attack against the propeller blade or the flow interaction between propeller and pod housing is quite different from the propeller design condition. The flow around them is very complex. Hence there is the difficulty for numerical estimating. In order to verify the applicability to wide range of the off-design condition, RANS simulations were executed. The calculation range for CPP was complete two quadrant condition each at several pitch setting. Regarding podded propulsor, pull type and push one having the common propeller and housing were targeted and the range of pod steering angle were set to all 360 degrees. Hydrodynamic performance as these calculated results were compared with published experimental results including the rotational moment of changing CPP’s pitch angle or steering the pod housing. Then, it was found that there were good agreements except for the particular kind of the operating conditions.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"16 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134258714","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 : 2019-03-27DOI: 10.3940/RINA.PRO.2019.10
N. Sasaki, S. Kuribayashi, Adrian Miles
This paper introduces full scale performance results obtained from voyage data taken from two 2400 dwt container ships, one equipped with the world’s first GATE RUDDER®. This is an innovative design, which is not seen as a conventional energy saving device and which has not been fully explored so far. The recent full-scale trials with this coastal container vessel have confirmed the superior performance of the GATE RUDDER® system which has shown 14% reduction in fuel consumption when compared with it’s sister vessel having a conventional rudder system. After 12 months from delivery, the voyage data from both vessels revealed that in some situations the gain could be much larger at abt. 27%. In this paper, the full scale operational performance differences from not only the model test but also the sea trial result are presented.
{"title":"FULL SCALE PERFORMANCE OF GATE RUDDER","authors":"N. Sasaki, S. Kuribayashi, Adrian Miles","doi":"10.3940/RINA.PRO.2019.10","DOIUrl":"https://doi.org/10.3940/RINA.PRO.2019.10","url":null,"abstract":"This paper introduces full scale performance results obtained from voyage data taken from two 2400 dwt container ships, one equipped with the world’s first GATE RUDDER®. This is an innovative design, which is not seen as a conventional energy saving device and which has not been fully explored so far. The recent full-scale trials with this coastal container vessel have confirmed the superior performance of the GATE RUDDER® system which has shown 14% reduction in fuel consumption when compared with it’s sister vessel having a conventional rudder system. After 12 months from delivery, the voyage data from both vessels revealed that in some situations the gain could be much larger at abt. 27%. In this paper, the full scale operational performance differences from not only the model test but also the sea trial result are presented.","PeriodicalId":193266,"journal":{"name":"Propellers & Impellers: Research, Design, Construction and Application","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122142737","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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