• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.456-464
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• 2016

To design the modified hull form with relatively unfavorable dimensions and constraints than the parent ship the stepwise design was applied. In each design step the resistance characteristics was estimated by numerical calculations using CFD programs as Wavis 1.4, Wavis 2.1 and Fluent 12.1. The wave profiles along hull surface by potential flow calculations were investigated to improve wave resistance by modifying the bow shapes. To improve the stern shapes with a point of viscous form resistance the pressure distributions on hull surface and the limiting streamlines are investigated by viscous flow calculations. The design objectives such as shortening the LBP, enlarging the propeller tip clearance, moving forward of the LCB location and increasing the displacement were applied by stepwise to develop the new hull form of DWT 75,000 product oil carrier. Finally a new hull form was developed without the resistance performance loss compared with the parent ship.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.1-7
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• 1998

Hull form development of the medium size high speed fishery patrol ship was carried out in the CWC at Chosun university. Same size of 15 knots class fishery patrol ship was selected as a parent form(Model number : CU-015), and modified fore and after body hull form under the slightly lengthened lo be suitable for the operation at 20 knots. To minimize the breaking wave in the vicinity of fore body at high speed zone, high bulb and sharp entrance angle were adapted. Meanwhile, to enlarge the engine room space keeping high resistance and sea-keeping Performance, U-type stern hull form was developed. Although the hull form was highly constrained in being limited to modification of a parent hull form significant wave resistance improvement was made.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.8-15
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• 2003

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using B-spline surface patches. The optimization method is applied to Series 60 hull and KCS(KRISO 3600 TEU Container Ship). The obtained results prove that the method is appropriate for preliminary hull form design.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.1
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• pp.3-10
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• 1990

Hull form can be described numerically by two approaches, one is to describe a hull form with a set of curves("curve approach"), and the other is to describe it with surfaces directly("surface approach"). This paper describes the numerical definition scheme of hull form using curve approach method which defines the hull form by a set of curves consisting of 2-dimensional transverse section curves and 3-dimensional longitudinal curves. A set of curves in the hull form definition scheme is described by the modified cubic spline which modified the general parametric cubic spline in order to ensure a very smooth curvature distribution within the curve segment even though a curve segment has large tangent angle at its end points. Illustrative examples are given showing the application of the method to represent the hull form of SWATH ship and oceanographic research vessel. Also, examples for hull form transformation are shown by using this method connected with transformation technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.467-474
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• 2018

The purpose of this study is related to automatic hull-form design for ships operating at two speeds. Research was conducted using a series 60 ($C_B=0.6$) ship as a target, which has the most basic ship hull-form. Hull-form development was pursued from the viewpoint of improving resistance performance. In particular, automatic hull-form design for a ship was performed to improve wave resistance, which is closely related to hull-forms. For this purpose, we developed automatic hull-form design software for ships by combining an optimization technique, resistance prediction technique and hull-form modification technique, appling the software developed to a target ship. A sequential quadratic programming method was used for optimization, and a potential-based panel method was used to predict resistance performance. A Gaussian-type modification function was developed and applied to change the ship hull-form. The software developed was used to design a target ship operating at two different speeds, and the performance of the resulting optimized hull was compared with the results of the original hull. In order to verify the validity of the program developed, experimental results obtained in model tests were compared with calculated values by numerical analysis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.17-22
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• 2004

This study was carried out at the CWC of Chosun university for the purpose of resistance performance improvement of planing hull, and the results of the tests were confirmed cooperatively with WJFEL. G/T 100 ton class planing hull form was selected, and the improvement of hull form including appendages were performed by using some model test techniques. The model test scope comprises resistance relative tests including wave profile observation, trim and sinkage measurement and flow visualization tests at full load and trial conditions for one bare hull and for two appended hulls. The final wedge and spray strip combined with improved hull form showed about 1.0 knot speed improvement at both of full and trial conditions, and outstanding improvement for fore wave phenomena.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.405-410
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• 2015

This paper reports the hull form development and resistance performance of a 5-ton-class catamaran-type coastal fishing boat. The weight estimation and preliminary design were basically extracted from existing coastal fishing vessels. In addition, the resistance performance was investigated using a model test in a high-speed circulating water channel and was analyzed in comparison to an existing catamaran fishing vessel. As a result, the modified hull achieved an approximately 30% reduction in resistance compared to the previous hull. The stability or boarding sensitivity of the modified hull form was more stable or comfortable than the original hull form based on a trim and sinkage comparison between the two boats.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.298-304
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• 2003

In this paper a free-form hull design program and performance prediction program for planing boat is introduced. This program enables the designer to do complex geometric hull shape design on a personal computer and accurately to predict power requirements for a given loading and velocity. For a free form design, Bezier curve model is adopted as a basic representation tool of curves and surfaces, and this program has versatile functions to do fairing jobs with a convenient graphical user interface. After creating a hull form the geometric data is provided in a manner compatible with a variety of analysis tools including 'Motion Analysis(by Zarnick)' for prediction of motion characteristics in regular waves, 'Running Attitude (by Savitsky)' for prediction of the running attitude and required power.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.1
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• pp.182-188
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• 1996

The hull form design is the first step of the concurrent ship design and production. At this point of view, to provide the hull form design system is very important to build the CIM system in shipbuilding. For this, we described about the functionality and the practices of the hull form design for the initial design stage based on the CIM concept. Also, we developed the hull form design system (DWHULL) using commercial 3D-CAD system. In the conclusions, we suggested the advance of the system and the direction of further development functions.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1234-1237
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• 1993

This paper discusses the hull form generation from fuzzy model constructed with actual ship data using fuzzy concept. SAC, which is the most important factor in the hull form generation, is expressed by a fuzzy model describing the relationships among design parameters, which have a great influence on SAC, through model identification process with the actual ship data and design parameters. Then, we can infer the SAC of an aimed ship through the process of fuzzy inference and decide the offset of a front view by making the fuzzy model between SAC and offset as well. In conclusion, this paper makes a step forward from the geometrical definition, which has been used for hull form generation so far, to direct mathematical formulae about the relationship between design parameters and offset. So, if the design parameters are given, we can generate the hull form taking such properties into account.