• 한국해양공학회지
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• 제18권1호
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• pp.80-84
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• 2004

The initial hull form of a 3 G/T and 30 knots class coastal leisure boat is newly developed. The performances measured, resistance, trim and sinkage, are investigated in a high-speed, circulating water channel (CWC). The effect of a fin attached on the hull side is studied together. Wave patterns are observed to clarify the relationship between the resistance performance and the wave characteristics. It can be found that the fin plays a role of increasing the resistance performance above a certain velocity.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.79-84
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• 2004

Initial hull form of 10 G/T and 40 knots class coastal patrol boat is newly developed. The resistance performances are experimentally and numerically investigated by model test at high speed circulating water channel(CWC) and CFD technique. The effect of a fin attached at hull side and initial trim are studied together. Wave patterns are observed to make clear the relation between the resistance performance and the wave characteristics. it can be found that the initial trim plays a role to increase the resistance performance above a certain velocity.

• 한국항해학회지
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• 제21권2호
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• pp.41-46
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• 1997

In this paper, important parameters of fast catamaran hull form are investigated. Praticularly, length-displacement ratio, demihull spacing, trim and hull form on resistance performance are analyzed. Also, the usefulness of SHIPFLOW program for hull form development is studied. The computed results by using SHIPFLOW program are compared with experimental results in model test.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 춘계학술대회 논문집
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• pp.47-53
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• 2005

본 연구에서는 최적화기법과 전산유체역학의 기술을 이용하여 저항의 관점에서 최적의 형상을 가지는 선형을 개발하는 알고리즘을 개발하였다. 최적화기법으로는 SQP(sequential quadratic programming)을 사용하였으며, 목적함수인 저항을 구하기 위하여 먼저 조파저항은 비선형자유수면경계조건을 고려한 선체주위 포텐셜유동을 계산할 수 있는 수치해석기법인 상방향패널이동법을 사용하였고, 선체에 미치는 전저항을 구하기 위하여 ITTC 1957년 모형선-실선상관곡선을 이용하였다. 선형최적화 과정 중의 선체의 변경이나 계산 격자의 생성은 NURBS(Non-Uniform Rational B-Spline)기법을 사용하여 구현하였다. 이와 같은 방법을 사용하여 개발된 선형최적화 기법의 타당성을 검증하기 위하여 선형이 비교적 잘 알려진 선형인 Wigley선형과 Series 60(C${_B}$=0.6)hull 선형에 대하여 설계속도 Fn=0.316에서 선형최적화를 위한 수치해석을 수행하고 그 결과를 초기선형과 서로 비교하였다.

• 대한조선학회지
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• 제1권1호
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• pp.9-16
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• 1964

As a pre-study for researches on powering characteristics of straight-framed V-bottom hull forms for usual commercial vessels, practicability of such a hull is investigated from viewpoints of over-all ship economy. For this purpose, a trawler hull of straight-elements with double chines, SV(T)-1, similar to Prof. Nevitt's W-8 in size and hull form coefficients was designed and tested at the SNU Ship Model Towing Tank for resistance measurements. The result is given in Fig.3 together with those of W-8 and other equivalent hulls of double curvature, such as FAO 135a-173, Doust and Takgi. The curves of the latters are reproduction of Prof. Nevitt's analysis, and given for comparison purpose. With in speed range of $9.0{\sim}10.5$ konts the resistance coefficients of SV(T)-1 are $18{\sim}25%$ higher than those of W-8, and $5{\sim}20%$ and $12{\sim}14%$ higher than those of FAO 135a-173 and Doust respectively. SV(T)-1, however, is slightly superior in resistance characteristics than Takagi's equivalent hull within the speed range. On the other hand, an equation for reduction rates of hull construction cost required to compensate for propulsion power increase in straight-elements hulls was derived from the definition of the economic efficiency of commercial vessels. The solution of the equation is given in Fig.4 graphically, from which it is known that $10{\sim}20%$ increase in propulsion power can be compensated by $8{\sim}16%$ reduction in hull construction cost. Considering simplicity and less equipments required in construction of straight -elements hulls, the author does argue for attainability of the above reduction rates in hull construction cost. Consequently, it is concluded that there is clear feasibility to adopt straight-elements hulls for usual commercial vessels of medium and small-size. And a further research will be done to obtain reliable data for chine shapes having good flowliness with the flow around ships depending on ship's size and speed.

• 대한조선학회논문집
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• 제49권5호
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• pp.391-399
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• 2012

This paper presents a method of hull form design for the assistant vessel which is used both as a lighting boat and a fish carrying boat for the fleet of newly formated purse seiner vessels. The optimum hull form parameters are searched by the Sequential Quadratic Programing(SQP) method with the power estimation method of Van Oortmerssen. The prismatic curve is redesigned from that of the reference hull by the Lackenby method. Through the modification of the hull form by using a CAD system, the design procedure is completed. The resistance performances of the reference and the modified hull forms are estimated by using a numerical simulation method. Also, the estimation of seakeeping ability and stability for the modified hull forms are carried out. And then, an optimum hull form is proposed for the designed hull form. Ship model tests for the reference and the designed hull forms are carried out at ship model basin. The results of the experiments show that the effective horse power of the designed hull form is about 22% smaller than that of the reference hull form at design speed. The designed hull form proposed in this study will contribute to the development of the hull form for Korean large purse seiner vessels.

• 대한조선학회지
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• 제7권2호
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• pp.19-26
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• 1970

Three kinds of high speed boat have been tested in the Seoul National University tank. Under the range of speed length ratio 2.5, displacement hulls have shown less resistance value than planing hull, but over the range of 3.0, planing hulls are better. Change of resistance due to the change of displacement is more severe in planing hull.

• 한국해양공학회지
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• 제30권4호
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• pp.235-242
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• 2016

In general, ship hull form design is carried out in two stages. In the first stage, the longitudinal variation of the sectional area curves is adapted from a similar mother ship to determine the volume distribution in ships. At this design stage, the initial design conditions of displacement, longitudinal center of buoyancy, etc. are satisfied and the global hydrodynamic properties of the structure are optimized. The second stage includes the local designing of the sectional forms. Sectional forms are related to the local pressure resistance in the fore- and aft-body shapes, cargo boundaries, interaction between the hull and propeller, etc. These relationships indicate that the hull sections need to be optimized in order to minimize the local resistance. The volumetric balanced (VOB) variation of ship hull forms has been suggested by Kim (2013) as a generalized, systematic variation method for determining the sectional area curves in hull form design. This method is characterized by form parameters and is based on an optimization technique. This paper emphasizes on an extensional function of the VOB considering a geometrical wave profile. We select a container ship and an LNG carrier to demonstrate the applicability of the proposed technique. Through analysis, we confirm that the VOB method, considering the geometrical wave profile, can be used as an efficient tool in the hull form design for ships.

• 대한조선학회지
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• 제26권2호
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• pp.1-12
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• 1989

본 논문에서는 선체로부터 멀리 전파해 나아가는 선형파와 선체 가까이에 존재하는 쇄파로 인한 조파저항성분을 최소화시키는 방법을 보여준다. 본 방법은 선형조파저항의 최적화 방법과 시험자료 분석을 통한 쇄파저항의 통계적 최적화방법으로 구성된다. 응용목적으로서, 수선형상이 포물선이고 측면이 수직한 모형을 기본선형으로 택하였고, 선형파를 최적화하는 방법과 경험적인 방법을 통하여서 선체전반부의 횡단면적 곡선을 변화시킨 두척의 수정모형선을 얻었다. 3척의 선형에 대한 시험 및 분석결과로부터 선체전반부의 횡단면적 곡선의 변화에 따른 선형파저항과 쇄파저항과의 상관관계를 살펴보았다. 본 방법으로 선체전반부가 최적화된 선형은 설계속도($F_n=0.26$)에서 기본선형에 비하여 약 47%의 조파저항감소를 보이고 있다.

• 대한조선학회논문집
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• 제43권1호
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• pp.43-49
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• 2006

The hull form of icebreaking tanker depends on the trade route and ice characteristic. The hull form has to be designed for icebreaking concept if the vessel is operating in heavy ice and also the hull from has to be optimized for general tanker when the ship is operating in ice-free ocean. This paper presents comparison of ship resistance in pack ice, level ice and open water. Four ships are used to compare the resistance characteristic. One is conventional tanker and three ships are icebreaking tankers. The ice model test was carried out at the IOT (Institute for Ocean Technology, Newfoundland, Canada) and open water test was performed at 55MB (Samsung Ship Model Basin). The ice resistance of conventional tanker was predicted by Colbourne's method. The resistance of open water, pack ice and level ice are compared and discussed. The best hull form of icebreaker is not good in open water performance compare to conventional tanker. This result explains that the hull form of icebreaker and normal tanker have to compromise when the ship is operated in ice and ice-free condition. The result of this paper gives a guide for icebreaking tanker design.