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The effect of level of the overflow outlet for continuous flow of solid particles on the pressure drop of a bubbling fluidized-bed that employed an in-bed inlet for solid feed was investigated with changing solid properties, solid feed rate, gas velocity, and level of the overflow outlet. The pressure drop of fluidized-bed (Δpbed,f) decreased with increasing gas velocity, but increased with either solid feed rate or level of the overflow solid outlet (L). The Δpbed,f/L increased with L. Irrespective of particle size and density, bed height converted for minimum fluidization condition (pressure head by bed weight, Hmf,f) decreased with increasing the volume flow rate of bubble but increased with either the solid feed rate or the level of the overflow solid outlet. The nominal vertical height, height between the Hmf,f and the level of the overflow outlet, that bubbles transported particles while drawing the solid particles out of the fluidized-bed increased as either the volume flow rate of bubble or level of the overflow outlet increased. However, it decreased as the solid feed rate increased. It appeared that the power of bubble for lifting solid to be discharged through the overflow outlet was same at the fixed volume flow rate of bubble, solid feed rate, and level of the overflow solid exit. The power of bubble increased with the level of the overflow outlet but not linearly. The correlation proposed for the pressure drop across the bubbling fluidized-bed was useful to predict the pressure drop across the recycle chamber of the loop seal and the external solid circulation rate in the circulating fluidized-bed system.

In this article, we review the recent progress and our research activity on the synthesis of inorganic shell nanostructures to enhance the catalytic performance and stability of metal nanoparticles in catalytic applications. First, we introduce general synthetic strategies for the fabrication of inorganic nanoscale shell layers, including template-assisted sol-gel coating, hydrothermal (or solvothermal) synthesis and the self-templating process. We also discuss recent examples of metal nanoparticles (NPs) with nanoscale shell layers, namely core–shell, yolk–shell and multiple NPs-embedded nanoscale shell. We then discuss the performance and stability of metal particles in practical catalytic applications. Finally, we conclude with a summary and perspective on the further progress of inorganic nanostructure with nanoscale shell layers for catalytic applications.

This work addresses the numerical study of wave-piercing planing hull and related hydrodynamic performance as the appendages. From the half century ago, the interest in high-speed planing crafts has been advanced toward maintaining performance stably. The main reasons to make it hard are instability motion occurring from porpoising and wave condition. Porpoising is mainly due to overlap the heaving and pitching motion with certain period, which is caused by instable pressure distribution and changing longitudinal location of center of gravity. In addition, in wave condition, encountering wave disturbs going into planing mode. This paper presents numerical results of wave-piercing planing hull in porpoising and wave condition. Numerical simulation is conducted via Reynolds Averaged Navier-stokes (RANS) with moving mesh techniques (overset grid), performed at different wave condition. The numerical results reveal motion characteristics overlapping porpoising and wave condition. At first, motions on low wavelength region show resonance on this condition, and some appendages enhance the motion amplitude larger than original values. Finally, this resonance was suppressed by stern appendages. However, momentum generated from stern appendages increases motions in high wavelength region. This effective motion corresponds with vertical accelerations from CG.

Flow properties of solids in an inclined standpipe were investigated while the solid particle was fed to the bottom of a bubbling fluidized bed (diameter 0.1m, 1.34m tall) via the standpipe and discharged out of the bed through the overflow exit. A group of K-based CO2 adsorbent particles was used as solids. The pressure drop of the fluidized bed, the height of solids bed in the standpipe, and flow rate of gas bypassing the fluidized bed through the standpipe were measured at room temperature and pressure as varying the fluidizing gas velocity, solids flow rate, and height of the overflow exit of fluidized solids. The pressure drop of the fluidized bed, the height of the solids bed in the standpipe, and the ratio of gas bypassing through the standpipe to the total gas in flow rate decreased with increasing the fluidizing gas velocity. Both the pressure drop of the fluidized bed and the height of the solids bed in the standpipe increased a little with the solids feed rate. The effect of the solids feed rate on the flow rate of gas bypassing through the standpipe could be ignored. The pressure drop of the fluidized bed and the height of the solids bed in the standpipe increased as the height of the overflow exit for solids increased in the fluidized bed. However, the effect of the height of the overflow exit on the flow rate of gas bypassing through the standpipe was negligible. Correlations on the pressure drop of the fluidized bed, the height of the solids bed in the standpipe, and the flow rate of gas bypassing through the standpipe were proposed successfully.

Dept. of Naval Architecture and Ocean Engineering, Mokpo National Maritime Uni, Mokpo, 530-729, Korea Division of Marintime Transportation System, Mokpo National Maritime Uni, Mokpo, 530-729, Korea요 약 : 현재 우리나라에서 사용되고 있는 등부표의 종류는 10가지 정도이며, 부표 설계 및 개발의 대부분을 외국 기술에 의존하고 있는 실정이다. 본 연구에서는 해상 계측 등이 가능한 소형 등부표의 개발을 목표로 소형 부표의 설계안을 제시하고 그 안전성을 수치적으로 검토하였다. 구체적으로는 다양한 실제 해상환경과 유사한 조우각과 선속 변화에 따른 내항성과 관련된 응답 진폭비, 부가저항 등의 값을 수치적으로 시뮬레이션하였다. 설계된 부표의 응답해석 결과, 종요응답비가 조우주파수의 증가에 따라 전체적으로 감소하는 특성을 확인하였다. 횡파에 대한 부가저항이 가장 크게 나타나는 것으로 분석되었고, 최종적으로 제시된 부표가 일정 조건하에서 응답 특성이 확보됨을 확인하였다. 핵심용어 : 해상계측형 등부표, 부표 설계, 운동성능, 조우주파수, 부가저항Abstract : There are currently 10 types of buoy, mostly which' design and development is dependent on foreign technology. In this study, it is aimed at the development of small instrumentation buoy and at the design proposal presented a numerically safety. The numerical method has the simulation of variety of marine environments, such as wave response amplitude ratio and each flux changes. Through the numerical simulation of buoy's kinetic movement, it is analyzed that Pitching motion increases by the frequency response of encounter and Added resistance appears to be the most significant on transverse waves. Finally, the proposed buoy is confirmed with the response' safety under simulation' conditions. Key Words : Marine instrumentation buoy, Buoy' Design, Kinetic movement, Encounter frequency, Added resistance1

In this study, a commercial seakeeping program Seakeeper, integrated into Maxsurf, which is based on the linear strip theory was employed to compare the effect of bulbous bow (with/without) on motion response characteristics in a 18-meter catamaran. The seakeeping analyses were conducted at several Beaufort wind conditions such as scale No. 3 (, =0.6m), No. 4 (, =1m) and No. 5 (, =2m) based on ITTC wave spectrum. Pitch motion response spectrum was calculated at Head sea, Head & bow sea and Beam sea as encounter angles. Hull form of a catamaran with bulb showed the maximum 20% decrease of pitch motion response as compared to that of hull form without bulb.

Research Associate, School of Marine Science and Technology, Newcastle University, UK Researcher, Dept. of Naval Architecture & Ocean Engineering, Mokpo National Maritime University, Mokpo, 530-729, Korea School of Marine Science and Technology, Newcastle University, UK Dept. of Naval Architecture and Ocean Engineering, Mokpo National Maritime Uni, Mokpo, 530-729, Korea요 약 : 본 연구에서는 전장이 26.75m인 해양플랜트지원선의 선형개발을 위한 수치해석을 수행하였고 수치해석 검증을 위한 1/10의 모형선 시험을 예인수조에서 수행하였다. 또한 운항해역의 해상조건으로 뷰포트 스케일 2, 3 및 4에서 향파, 선수사파 및 횡파에서 선속별 상하동요 및 종동요에 대해서 운동응답특성을 수치 해석하였다. 모형시험과 수치해석의 저항 예측 결과는 상호 일치하였다. 운동응답특성은 선수파에서 상하동요는 조우주파수 1.8~2.0 영역에서 크게 나타났으며, 종동요는 거친 해상에서 선미사파 및 고속영역에서 높은 운동특성을 보였다.핵심용어 : 해양플랜트지원선, 모형시험, 선형개발, 선체운동응답, ITTC 파스펙트럼Abstract : In this study, numerical hull form development of a platform supply vessel, a full scale with the overall length of 26.75m, was performed to predict a bare-hull resistance and a large scale of model tests with a 1/10 scaled model were conducted to verify the success of numerical results. Numerical analysis on heave and pitch motion as a function of encounter frequency and ship’s speed for the prediction of seakeeping characteristics are also presented. The experiment results of resistance agreed well with numerical analysis. As a result in the motion response characteristics, the heave RAO indicates high values with the range of encounter frequency 1.8~2.0. The Pitch RAO indicates high motion response characteristics at Beaufort scale No. 3 and 4 in rough seas. Key Words : Platform supply vessel, Model test, Hull form development, Ship motion response, ITTC wave spectrum1

Tip vortex structure around a NACA 0018 foil with and without an endplate is studied using PIV method in a circulating water channel. The Reynolds number based on the chord length (100 mm) is Re=2.5×10 4 . The analysis also includes varying angles of attack α =10° and α =20°. Velocity profiles are obtained from 1C (chord length) to 3C, measured from the trailing edge. Sectional velocity profiles are also obtained and compared both foils at the same angles of attack. Vortex formation is changed near the end-span section due to the prevention of roll-up phenomenon. The endplate also decreases Reynolds shear stress in the wake region. It can be judged that the flow formation around the foil is affected by the endplate untill the mid-span.

An experimental study is carried out to investigate the near-wake characteristics of a NACA 0018 foil with a flat plate. Two-frame grey-level cross correlation PIV method is used to measure the local flow characteristic around a pitch damping foil to control the vertical motion of high speed crafts in a circulating water channel. The analysis also includes angles of attack 10 and 20 degrees respectively. Reynolds number based on the chord length(C=100mm) of NACA0018 has been applied during the whole experiments. The distance between the foil and the flat plate is D/C=0.5, 1.0 and 1.5 respectively. The channel effect according as the distance between the foil and the flat plate has a close relation with the velocity distributions around the foil. In the wake of 20-degree of attack, the complex turbulent flow and a thick boundary layer are formed due to the processes of vortex generation and dissipation.

An experiment was carried out to figure out the turbulence flow characteristics in the wake of the transom stern's 2-dimensional section by 2-frame grey level cross correlation PIV method at Re= 3.5×10 3 , Re= 7.0×10 3 . The angles of transom stern are 45°(Model "A"), 90°(Model "B") and 135°(Model "C") respectively. The depth of wetted surface is 40mm from free surface. Strong turbulence intensity appears at the interaction between the flow separation of the bottom of a model and the free surface. This study provides statistic flow information such as turbulence intensity, Reynolds stress and turbulence kinetic energy. Model C type (Raked transom) has low Reynolds stress and turbulence kinetic energy.

Graduate school, Faculty of Marine Engineering, Mokpo National Maritime Uni, Mokpo, 530-729, Korea Dept. of Guard and Safety, West Regional Headquarters, Korea Coast Guard, Mokpo, 530-420, Korea Dept. of Naval Architecture & Ocean Engineering, Mokpo National Maritime Uni, Mokpo, 530-729, Korea Faculty of Marine Engineering, Mokpo National Maritime Uni, Mokpo, 530-729, Korea요 약 : 본 연구에서는 자유낙하하는 직사각형 해양구조물(800×250×50㎣)의 슬래밍 충격압력 및 유동특성을 알아보고자 실험을 수행하였다. 유동장의 계측은 2-프레임 그레이레벨 상호상관 PIV기법을 이용하였으며, 자유낙하하는 모델의 충격압력은 압력계측장비(Dewatron)를 이용하였다. 모델과 자유수면간 이루는 각은 10°와 20°를 적용하였다. 속도장은 접수보다 이수에서 빠른 유동특성을 나타냈다. 모델 하부에서 충격압력이 가장 높은 지점인 P2 지점에서 10°보다 경사각이 큰 20°에서 약 6% 상승하였다.핵심용어 : 슬래밍, 자유낙하, 충격압력, 유동장, 접수, 이수Abstract : This paper presents an experimental investigation to figure out slamming impact pressure and flow characteristics of a rectangular Marine structure(800×250×50㎣) in free fall. The flow field has been obtained by 2-frame grey level cross correlation PIV(Particle Image Velocimetry) method, the impact pressure of the free fall model by a pressure acquisition system(Dewatron). The angles between a model and the free surface are adapted 10° and 20° respectively. Velocity field of water exit has higher better than water entry. The highest point, P2 of impact pressure under the bottom of the model has been appeared about 6% higher values at 20 degrees than 10 degrees.Key Words : Slamming, Free fall, Impact pressure, Flow field, Water entry, Water exit1

This study gives the vertical motion analysis in multi-directional irregular waves using a commercial code(MAXSURF v.16) based on linear strip theory for a training ship. To verify the commercial code prior to the analysis, we guarantees the reliability of this paper`s results using the commercial code by comparing with the results(Flokstra, 1974) of same hull and experimental conditions on a Panamax container. The analysis conditions are Beaufort wind scale No. 5($\bar{T}

An experiment was carried out to figure out the instantaneous flow characteristics in the wake of the transom stern`s 2-dimensional section by 2-frame grey level cross correlation PIV method at $Re

Flow control by rods of various sizes attached to the rearward stagnation point of a circular cylinder is investigated in a circulating water channel using a 2-frame gray level cross-correlation Particle Image Velocimetry (PIV) technique. Experiments are performed at Reynolds numbers between Re=5000 and Re=20,000, based on free stream velocity and the main circular cylinder diameter (D=50 mm). Time-mean velocity fields, turbulence intensity, and Reynolds shear stress are measured with four control rods and four step Reynolds numbers. The wake formation behind a cylinder was influenced by the interaction between the upper and lower sides of the wake, due to the effect of the control rods. Each control rod had distinctive characteristics. However, there was no one optimum control rod for all Reynolds numbers. The control rod d/D=0.3 had an outstanding effect on reducing the turbulence intensity, with vortex formation strongly suppressed by the control rod in its near wake. Strong turbulence intensity appeared within X/D=2.5 for all cases.

In physical engineering, the turbulent flow on the surface roughness is very important. With the welding, design and paint, the hull surface roughness at each stage in the various aspects are important factors to be considered. In this study, the hull surface roughness geometry that was generalized to the PIV was applied to the tank test. The roughness of the surface changed the distance of the interval. Experimental velocity is Re

*Researcher, Mokpo National Maritime University, Mokpo, 530-729, Korea †Graduate School of Mokpo National Maritime University, Mokpo, 530-729, Korea** Division of Ocean Engineering, Korea Maritime University, Busan, 606-791, Korea*** Division of Ocean System Engineering, Mokpo National Maritime University, Mokpo, 530-729, Korea요 약 :해양의 다양한 환경에 노출된 선체 표면의 거칠기를 일반화 하여 모델 실험을 PIV기법을 적용하여 회류수조에서 수행하였다. 모델의 유동방향 표면 거칠기의 폭에 기초하여 본 연구에 적용된 레이놀즈수 Re=1.0×103에서 유동가시화, 시간평균 속도장 및 와도장을 상호 평가를 통하여 유동특성을 조사하였다. 와의 생성과 소멸 메커니즘을 통해 와류의 중심은 표면 거칠기 높이의 0.5H로 나타났다. 또한 거칠기 계수가 증가함에 따라 와의 크기와 비례하고, 와의 생성위치도 상부와 전방으로 이동하였다.핵심용어 : 표면거칠기, 입자영상유속계, 유동가시화, 속도장, 와도Abstract :The experimental study of the hull surface roughness on a developing turbulent boundary layer which exposed to a variety of operating environments were investigated by performing particle image velocimetry(PIV) in a circulating water channel. The Reynolds number based on the width of roughness was about Re=1000. the roughness elements used were periodically arranged two-dimensionally. the flow visualization, time-mean velocity fields and vorticity fields to measure the flow characteristics were obtained. The investigation shows that the vortex generation and its progress inside the walls. And the center of the vortex was located at the middle of the height of the surface roughness.Key words :Surface roughness, PIV analysis, Flow visualization, Velocity field, Vorticity †교신저자 : 연회원, woojunoh@mmu.ac.kr 061)240-7142 * 연회원, domingo@mmu.ac.kr 016)614-3001 ** 연회원, kaigan@hanmail.net 051)410-5293*** 종신회원, kwlee@mmu.ac.kr 061)240-7307

A very good seakeeping vessel is able to operate effectively even in high sea states and also the passengers and the cargos are ensured in good conditions. The motions of a high speed boats are highly influenced by speed and dynamic forces even in encounter frequencies so that the assessment of seakeeping ability of the design craft in an early stage needs to be calculated for all three motions and for all ralative wave headings. In this paper, it concludes that RAO and RMS values of the catamaran`s 3 motion are calculated according as the variation of Beafort scales and ship`s speed. The ship motion response of the catamaran based on the RAO and RMS by encounter angles and speed was calculated.

An open water rudder test was carried out to figure out the flow characteristics around a twin rudder at $Re

The free surface influenced the wake behind a circular cylinder and its effects were investigated experimentally in a circulating water channel with the variation of water depth. Instantaneous velocity fields were measured in this paper. The measured results has been compared with each other to investigate the flow characteristics of the circular cylinder`s 2-dimensional section at $Re

Automation is being accepted for control systems onboard ships in view of the shortage of skilled manpower in marine sector. Control theory has long been applied to maneuvering problems and at present this trend is continuing at an increased rate. This is for speed control, course control and path keeping. Heading control and course keeping are very important for surface ships while they enter shallow water regions. A typical situation is the entry of a large commercial ship into the harbour basin. The ship faces a sudden change of forces and moments around it due to the change in the hydrodynamics. The Master of the ship regulates the speed while entering the basin. Forces and moments, due to the hydrodynamic flow around the moving hull, are balanced by the rudder behind it. The feed back from the heading angle is taken and the gain in the control system prompts the steering gear to turn the rudder. The conventional control algorithm based on PID is attempted in the first part of the paper and case studies are shown for a Mariner class ship whose hydrodynamic derivatives are known. Displacement, velocities and accelerations are determined for short duration from the simulation of a voyage in calm water. The proposed system can be implemented into autopilot systems. The codes developed in MATLAB can accommodate wind and wave forces as well. The simulation is of a general type and can be used for other vessels with a change in the constants of P (Proportional), I (Integral) and D (Derivative) which can be arrived at by trial and error. The design of the control system depends on the choice of the three control constants Kp, Ki and Kd. These will change as per sea state and extra loads. The control of motions in shallow water and deep water cases are discussed in the paper. In the next part of the paper, fuzzy logic control is discussed. Fuzzy logic is applied to control the heading and bring the path of the vessel to the desired level. The models discussed are versatile because of the provision for add-on facility for wind, wave or any other environmental loads. The rudder turning rate is taken as that for commercial ships. In the near future, a combined control system for ship maneuvering can be possible by considering both the PID and Fuzzy based algorithm. The two algorithms with suitable modifications are useful for non-linear cases. It is also tried to compare the two methods and an attempt is made to find out which is better and acceptable. � 2008 Elsevier Inc. All rights reserved.

Estimation of the buckling and ultimate strength of a continuous stiffened plate subjected to combined transverse compression and lateral pressure is of high importance to ensure the safety of ship structures, particularly for the bottom plating under a deep draft condition For example, bottom plating of bulk carriers is subjected to transverse thrust caused by the bending of double bottom structure and the direct action of pressure on the side shells. Most of experimental tests, theoretical approach and numerical researches have been performed on the buckling and ultimate strength behaviour of plates or stiffened plates under combined compression and lateral pressure. With regard to stiffened panels, however, most of studies have been concerned with the load conditions of combined longitudinal thrust and lateral pressure, while fewer studies have been performed for the combined transverse thrust and lateral pressure. In addition, the previous researches are mainly concerned with an isolated rectangular plate simply supported along the all edges, whereas actual ship plating is continuous across the transverse frames and heavy girders. In the present paper, a series of elastoplastic large deflection FEA on a continuous stiffened plate is performed and then clarify the characteristic of collapse mode and explain the effect of transverse compression.

The main purpose in having a control surface on a ship is to control the motion of it. It is the important element to determine the maneuvering characteristics of the ship. In this paper, the measured results has been compared with each other to predict the performance characteristics of flapped rudder`s 2-dimensional section at $Re

Flow characteristics of the control-rod-attached 2-dimensional circular cylinder was accomplished using by PIV techniques. model tests had been carried out with different diameters of control rods(d/D

The purpose in having a control rod on a buoy system is to control the motion of it. The system may be composed entirely of a single circular cylinder and a long mooring anchor cable. A control rod has one function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of the effects of mutual interference. then determine the stability characteristics of the body. In this paper, the study of control-rod-attached buoy`s 2-dimensional section was accomplished. model tests and numerical simulations had been carried out with different diameters of control rods. and varying the Reynolds number $Re

In this paper, the wave pattern around the hull with the transom stern advancing on the free surface with a constant speed was taken into consideration. To solve the problem the numerical analysis program was developed using Rankine source panel method based on potential flow analysis technique. The non-linearity of the free surface boundary conditions was fully satisfied. To verify the validity of the developed program the numerical calculations for Athena hull and KCS(KRISO container ship) hull was performed. The results of the numerical computation was compared with the ones of the model test experiment.

A rudder roll control system is developed and analyzed to control the yawing and rolling motion of ship in irregular waves. The 4-DOF maneuvering equations of motion are derived to carry out the simulation of the motion of a ship and the wave forces are considered as the external forces of a ship in the simulation. The wave forces in the time domain analysis are generated from the frequency transfer function calculated by 3-D source distribution method. The rudder roll control system is developed by linear combination of PD rudder controllers of yawing and rolling motion. Rudder rate speed and Schilling rudder are considered to increase the roll reduction efficiency.

This paper is a continuation of a technical note published in Ocean Engineering in Vol. 30 (2003). Stability of Ro-Ro ships was subjected to rigorous investigation by many researchers recent past. Stability of a ship is to be ensured during design stage for various loading conditions. Two typical conditions of departure and arrival are usually chosen by naval architects. Out of all types of motions of a ship, the critical motion leading to capsize is the roll. Ship roll motions are very complicated and difficult to analyze, as there are various parameters involved in the motion. Large angle roll motions are nonlinear in many aspects. For larger angles of roll many nonlinearties become significant. Various representations of damping and restoring terms found in the literature are investigated and their solutions are analyzed. Data of a Ro-Ro vessel is used to demonstrate the applicability of the proposed procedure. In the present study, the problem of ship safety has been considered with regard to the rolling motion of a ship in beam waves. A parametric investigation is undertaken to identify and quantify the effect of a number of key parameters viz., wave slope, wave frequency etc. on the capsizing conditions of a ship. Nonlinear response of ship is determined in the frequency domain.

Experiments revealed that green water phenomena resemble dam-break, in which flow over deck edge forms a vertical wall of water and suddenly falls down into deck. In this paper the dam breaking problems were formulated using Glimm's algorithm, so-rolled, Random Choice method and, several validations were presented.

FPSOs are commonly proposed and used for offshore oil production. Due to the fundamental requirement of FPSOs to remain moored at their location, they are unable to avoid severe weather. FPSOs normally operate head to the weather, and sensitive equipment located near the bow will be susceptible to green water damage. Damage may occur to both equipment and superstructure, with resulting risk to personnel. To initially access green water is allowed by the physical understanding of green water events. In this paper the main focus is put on the physical phenomena of green water accounted for with the tested data in regular waves.

The concept of live fish tanks in trawlers is to use the catch in a better condition and to reduce marine pollution. It also reduces the infrastructure meant to freeze the catch to preserve it for longer period. But the presence of additional free surface in the vessel challenges the stability of the vessel. This is besides the sloshing effect due to the moving liquid mass in the tank. Roll motions are initiated due to various factors related to the hull characteristics of the vessel, loading and operating conditions and its interaction with the environment. Location of fish tank, its orientation, arrangement of baffles inside the tank to reduce the free surface affects and careful design of tank opening are to be given priority during the design, manufacturing and tank testing. The results obtained from tank test of model are compared with that of analytical method. The non-linear roll performance become further complicated due to the free surface and sloshing effects of the mass in the live fish tank. Wave makers are used for generating waves under laboratory conditions compatible with the scaled down model of the trawler model. The tests are conducted in the towing tank of Pusan National University. ? 2005 Elsevier Ltd. All rights reserved.

The optimum design of bow structure of power yacht belongs to the non-linear constrained optimisation problems. The determination of scantlings for the bow structure is a very important issue within the whole structural design process. The derived design results are obtained by the use of real-coded micro-genetic algorithm including evaluation from Lloyd's Register small craft guideline, so that the nominal limiting stress requirement can be satisfied. In this study, the minimum volume design of bow structure on the power yacht was carried out based on the finite element analysis. The target model for optimum design and local structural analysis is the bow structure of a power yacht. The volume of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. During optimisation procedure, finite element analysis was performed to determine the constraint parameters at each iteration step of the optimisation loop. Optimisation results were compared with a pre-existing design and it was possible to reduce approximately 19% of the total steel volume of bow structure from the previous design for the power yacht.