In this paper, the procedure of generation and application of nonlinear wave loads for structural design of large container carrier was described. Ship motion and wave load was calculated by modified strip method. Pressure acting on wetted hull surface was calculated taking into account of relative hull motion to the wave. Design wave height was determined based on the most sensitive wave length considering rule vertical wave bending moment at head sea or fellowing sea condition. And the enforced heeling angie concept which was introduced by Germanischer Lloyd (GL) classification had been used to simulate high torsional moment in way of fore hold parts similar to actual sea going condition. Using wave load generated from this dynamic load calculation, FE analyses were performed. With this result, yielding, buckling, hatch diagonal deflection and fatigue strength of hatch corners were reviewed based on the requirement of GL classification. The results of FE analysis show good compatibility with GL classification.

Sloshing loads, produced by the violent liquid free-surface motions inside the cargo tank have become an important design parameter in ship building industry since there have been demands for the increased sizes of the cargo containment system of LNG carriers. In this study, sloshing impact pressure acting on the shell of the spherical cargo tank of an LNG carrier as well as dynamic pressure and flow behavior around the pump tower located at the center of the tank have been calculated. Comparative numerical sloshing simulations for a spherical LNG tank using 2-D LR.FLUIDS which is based on the finite difference method and 3-D MSC.DYTRAN which is capable of calculating nonlinear fluid-structure interaction have been carried out. A method of calculating sloshing-induced dynamic loads and the subsequent structural strength analysis for pump tower of a spherical LNG carrier using MSC. DYTRAN and MSC.NASTRAN have been presented.

An attempt to improve the speed performance through the minimizing in wave resistance has been done by an application of gooseneck and no bulb type to bulbous bow for the DSME 78,500 Class LPG Carrier on the basis of the CFD calculation and comparatives model tests. The hydrodynamic characteristics according to the variation of the shape of Cp-curve, design load water line, frame line and bulbous bow that have an important effect on the wave resistance has been evaluated/calculated by ship-flow code. A wide variety in hull variation have been tried to have a good hull form with three types of fore-body hull forms mainly classified by the shape of bulbous bow. The speed performances for the three final hull forms with different bulbous bows have been evaluated through the model tests.

The present study is concerned with the numerical analysis of the sloshing impact pressure of the Liquefied Natural Gas (LNG) carriers in rough sea. The reliable predictions of the both random tank motions in irregular waves and violent fluid flow in the LNG tanks are required for practical sloshing analysis procedure of LNG carriers. The three-dimensional numerical model adopting SOLA-VOF scheme is used to predict violent free surface movements of LNG tank in irregular motions. For accurate input motion of tank, a three-dimensional panel method program called SSMP (Samsung Ship Motion Program) is applied for seakeeping analysis. Comparison studies of sloshing analysis are carried out for No.2 tank of 138K and 205K LNG carriers to verify the safety of the LNG containment system of the proposed 205K large LNG carrier.

Since a cavitation pattern in model scale can be different from that in full scale, it has been highly demanded to measure a fluctuating pressure induced by propeller in full scale. For the verification of the cavitation test for 105K lanker in the large cavitation tunnel in Samsung Ship Model Basin(SSMB), an effective pressure fluctuation measurement system was developed and a series of full scale measurements was carried out. These results were compared with those of cavitation tests in SSMB. The measured results in full scale gave good agreements to those in model tests. The fluctuating pressure at $2^{nd}$ blade frequency in full scale seems to be highly dependent upon tip loading.

In this paper, a correlation analysis of wake distribution between model test and CFD was described. CFD calculation was performed by 'WAVIS' which is utilized in hullform development. By using the correlation between model test and CFD, we have estimated M/T wake distribution To control M/T and CFD wake distribution effectively. we have developed the program that it is possible to export to TECPLOT and visualize wake distribution.

STX shipbuilding Co,. Ltd. has been developed a hull form and propeller of medium class container vessel. The present paper deals with numerical calculations and experimental tests for the investigation of wave resistance, viscous resistance and propeller. The characteristics of wave resistance and self propulsion factors are varied in order to find an optimized hull form. The measured results have been compared with computed results by 'WAVIS' The prediction of the caviation occurrence was predicted by 'Opti-pro' and measurement is performed in KRISO.

Optimum design of the big brackets is performed through iterated 3-D FE analyses to meet the permissible limits of stress, which consumes an excessive amount of calculation time. Therefore, this study has been prepared to determine rapidly and accurately an optimum size and scantling of the big brackets at the initial design stage. The generalized slope deflection method (GSDM) based on the span point concept is applied to enhance the efficiency of iterated structural analyses. The accuracy and applicability of the present method is verified by comparing with a detail 3-D FE analysis of web frame structures. As an optimization technique, evolution strategies (ES) are applied using discrete design variables for practical design.

Recently it was reported that the vibration problems on the oil pipe support structure of the crude oil carrier were occurred. in order to investigate the vibration characteristics and the causes of the vibration occasionally. the vibration measurements and impact tests for the oil Pipe structure were carried out. From the measurement results severe vibration was caused by the resonance between the transversal natural frequency of the structure and $6^{th}$ order excitation force of the main engine. Providing the proper countermeasures a series of the vibration analyses were carried out based on the measurement results. From the analysis results, it was concluded that the vibration characteristics of the oil pipe structure were affected by the oil pipes, support structure itself, upper deck structure and the installation spaces and the standard design was established for the crude oil carriers.

Membrane type LNG Carriers are characterized by their special structures such as trunk deck above upper deck. It is necessary to introduce an appropriate structure arrangement taking into account transition of the trunk deck to the upper deck or deckhouse in fore and aft parts. The transition area at aft part -from trunk deck to the deckhouse - is to be specially considered because of high longitudinal stresses applied at the area. This study has been carried out to tackle the transitional structure problem in design stage This paper deals with not only mesh size of FE models for scantling evaluation and fatigue assessment but also technical issues regarding fatigue assessment.

The double hull VLCC(Very Large Crude Oil Tanker) have been designed to have each four(4) longitudinal bulkheads and transverse bulkheads in general. Actually, the inside longitudinal bulkheads among four(4) longitudinal bulkheads, which are extended up to the end of the aft cargo hold for continuity of the members, have been designed with knuckled type inboard due to the narrowed hull shape at bottom region, but sometimes the straight type of longitudinal bulkheads were adopted based on the degree of the hull lines shape. However, regardless the type of longitudinal bulkheads, inside and outside longitudinal bulkheads conflict each other in aft cargo hold region This makes the structure more complex thus giving difficulties to structural design and production. Recently, a vessel of straight type was reported to have cracks on bracket end and tripping bracket toe in aft cargo hold region. As a solution to this problem, in designing the first 60m Beam VLCC, DSME developed a new cargo hold structure which is good in production and structural point of view by structural strength and fatigue analysis of fore and aft cargo hold.

This paper presents the results of the reliability analysis of PAU (Preliminary Assembly Unit) seat of the floating Production Storage and Off1-loading Unit (FPSO) The main aim of the analysis was to demonstrate that a sufficient safety of structural members is guaranteed against PAU loads, internal and external pressure, and hull girder moments. Topside loads for PAU design are based on owner's request. According to the seat type, topside loads are classified into maximum values of same seat type for design efficiency. Totally, 26 loading cases for each model are used for this analysis with the combination of the reactions of PAU loafing and the hull girder bending moments according to LR offshore (2). The analysis results are evaluated according to the acceptance criteria for yielding given in LR offshore and guidance note (3) and The panel buckling resistance is verified by LR offshore and SDA (4). For 900,000 bbls FPSO, the PAU support foundation analysis using 3-D F.E. model is carried out to verify the structural adequacy of PAU foundation and structure members in way of PAU. The modified structures in way of PAU support are safe against considered load cases and all stresses in way of PAU support are within design criteria.

According to the trends of construction of large size vessel with high power the natural frequencies of the bending modes of propeller blades have been lower than the past. Therefore, it is expected that the noise and vibration problems of the marine propeller are frequently occurred. As main issue of the propeller noise and vibration problem, the cavitation noise and singing noise due to the flow induced excitation of the bending modes of propeller blade in the high frequency range has been studied by the hydrodynamic researchers in the view point of the excitation force reduction. In this paper, the vibration mode characteristics of propeller with a large diameter in very large vessel are investigated by the vibration analysis of the finite element method using MSC/Nastran and the vibration measurement by the impact test on the propeller blade. According to the results, the natural frequencies of various blade bending modes in water entrained condition could be estimated from the natural frequencies taken by the measurement and free vibration analysis in the dry condition, and it could be estimated how the high frequency noise such as singing is generated from the blade bending modes.

During assembling the ship block, the lifting and turnover events are not only inevitable but also very important for safety aspects and block accuracy. However, they have been executed in empirical ways rather than numerical ways in consideration of the building schedule. In this paper, a structural analysis has been carried out for the container ship side block that collapsed in the course turnover stage. As a result, the causes of collapse and countermeasure plans are presented.

This paper describes introductory remarks on risk management and risk-based design for ships and offshore installations with potential hazards. Clients' requirements on safety and performance was related to the risk management and risk-based design. A general procedure for risk-based design was also suggested with each step explained in detail. Various risk-based design approaches were emphasized with their needs and methodological characteristics taken into account. Related rules, standards, and regulations were summarized. The last part included recommendations for Korean ship building industries about the risk management and risk-based design.

DSME has successfully developed the unified CAD system (DACOS) for the commercial ship based on its design know-how accumulated for several years. Currently, DSME is expanding the unified CAD system to plant and special ship design. In this paper, the development of pipe design, especially, isometric drawing and BOM(Bill of Material) generation will be introduced isometric drawing and BOM generation are major activities of pipe design in shipbuilding. The drawing is used for pipe construction and installation while the BOM is used for purchasing and manufacturing pipe line. These activities are time-consuming and tedious jobs done by designers because the drawing should be generated as a non-scaled symbolized drawing that can be easily understood and the BOM information should be extracted without mistake. Therefore, we implemented automatic isometric drawing and 80M generation system for pipe design. In this paper, the developed system and the used technology will as well be introduced and a design output in a plant project as an applied example will be illustrated.

Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

Recently, it is much more required to approach the accurate shaft alignment analysis according to the tendency of active showing in large container vessel and that of the heavy weight of propeller in connection with it. Shaft alignment calculation lies upon how the pressure apply on bearings properly in operation of main engine and how the stress of shaft puts within that of limit of bearing material and how the movement of shaft is prospected owing to propeller forces and moments. Therefore, we have conducted the shaft alignment calculation of very large container vessel considering the deformation of hull structure and the propeller forces and moments and the static and dynamic condition of shaft. The calculation results show the pressure distribution of aft bush and the movement of shaft in bearing. The shaft alignment calculation helps the stable application of shaft alignment, which was proved in sea trial.

The size of ship is being larger than the past in the shipping industry thanks to the increased quantity of goods transported by ship. Therefore, HHIC (Hanjin Heavy industries & Construction co., LTD) invented innovative construction method, so called 'DAM', to build a ship which is longer than the length of the HHIC's dry dock. On Erection at the sea by the application of DAM Method, Squeezing & Detachment of A/F film may occur as a result of the wave and the constriction between A/F film pre-applied on the side shell and DAM's Rubber Packing. Thus, the test for finding the minimum curing time of A/F film was performed to protect Squeezing & Detachment of A/F film on the hull. To verify the soundness of paint and to find the optimum condition during the erection period of the DAM, laboratory test was carried out under no immersion condition through the application of various coatings on the Rubber Packing. And two methods were selected from the results of laboratory test for actual MOCK-UP Test. In addition, the test for the film profile per temperature of silicone A/F coat and the film Squeezing was performed.

It is important to control material flow in shipbuilding as it decides the productivity of production, cost and period of production. The weight of material in a big shipyard is even more one million tons. The results contained in this paper can provide the valuable information on the effect of reduction of cost and competitive power. The intention of this paper is to let ship builders pay attention to material flow. This paper refers to other manufacture's methods to improve their material flow and also give one example to show how to pursue to improve material flow in a shop. We have still lots of room to improve material flow.

In this paper, we study some problems of the scheduling on the fixed area in a shipbuilding. The scheduling, constrainted a working area, is not easy to make a load balance and to operate a change of daily work plan. we proposed a block arrangement algorithm to make the load balance and developed a system used to operate the change of daily work plan.

The weight of a ship depends on the size of the ship. Normal lightweight of a ship is over 10,000 tons. So it is inevitable to divide a ship into about more than hundreds of lumps. Each of lumps is called as a block in shipbuilding. The sizes of blocks are decided by a yard's facilities. Among them lifting cranes are most decisive facilities. By block's size the productivity of a yard is decided very much. So it is very important to have a proper block division during shipbuilding. This paper refers to the recent trend of block division among yards. This paper would give an idea how to decide boundaries of blocks. Block division also decides both quality of a ship and work volume of it. These days the block erection method is changed dramatically due to use sea barge mounted crane for erection of a grand ring block. This paper explains the new trend of block division in shipbuilding.

This paper presents a novel Intelligent-Welding-Carriage (IWC) for automation of curved block in shipbuilding. The curved block is usually used in both front and back side of the ship. In curved block root gap is big, 1-7 (mm) and inclination, 0-30 (deg). Since available conventional carriage type is limited to use below root gap of 3 (mm), only manual welding is employed in curved block. To adopt an IWC in curved block, it requires control of the welding conditions, i.e., voltage. current, weaving speed, dwell time and travel speed, with respect to root gap and inclination to achieve good welding qualify. In this paper, an IWC is developed for automization of welding operation to accommodate gap and inclination. Kinematics model and dynamics using Lagrangian formulation of the manipulator is introduced. IWC utilizes a database to perform accurate welding. The database is programmed based on numerous experimental test results with respect to gap, inclination, material, travel speed, weaving condition, voltage, and current. Finally, experimental result using PID control is addressed for verifying the trajectory tracking accuracy of end-effector.

This paper is concerns with the development of the formulae to predict deformation of curved plate due to line heating. For this purpose thermal elasto-plastic analysis has been carried out for both flat and curved plate models with varying parameters which affect the result of line heating. based on the results of numerical analysis, the formulae for predicting angular deformation has been derived through the regression analysis, which. It has been seen that the present model well agrees with the numerical analysis results and can reflect the curvature effect of plate to be heated. This paper ends with some comments on this formulae.

Korean naval architecture company today is making researches in expansion of productivity of their own accord. In result, they have accomplished many technical developments like a ground shipbuilding system. For our company's productivity expansion in our yard's limited condition (the facility, P.E area, stock area), we develop isometric pre-erection method that turn into a possibility to maximize our facility use, minimize our dock period.

A welding bead height is closely related to the efficiency of welding work, and the height of 3mm is used in the conventional practice of butt welding. in the present paper, the modification of bead height from 3mm to 6mm is considered to increase the efficiency and work productivity of butt welding on bottom plate (of BONGA FPSO actually built in SHI shipyard). Therefore, fatigue analysis has been carried out using simplified method based on the DNV Rules. It is found that the minimum fatigue life is about 594 years and the butt welding details with 6mm bead height has sufficient strength and resistance against fatigue.

Reduction of labor hour for cleaning up of the used abrasives after blasting. is attempted by improving the efficiency of abrasive recovery process in the protective coating of ship's block, For this purpose, the theoretical background for pneumatic transport technology in the abrasive recovery system as well as experimental evaluation on the effect of design parameters such as flow pattern, saltation velocity and pressure drop on the efficiency of the abrasive recovery system are employed . By optimizing the operating parameters such as the length and diameter of the suction hose, specification of recovery device and recovery mouth, a new method which can dramatically increase the efficiency of abrasive recovery system, is proposed.

As design trends has changed to have flexible aft hull structure, increased power output and stiffer shafting system, owners and classification societies have more concerned about shaft alignment. In the shaft alignment analysis, there are many uncertainties which are related in propeller generated force, bearing stiffness, crank shaft model and etc. in this study, it is focused on the effect of crankshaft model by comparing between equivalent model and actual crankshaft model.

The binary Al-Mg alloys are the basis for the 5000 series of non-heat-treatable aluminum alloys. In general, 5000 series of aluminum alleys have a high strength, good welding characteristics and a high resistance to corrosion, especially under the seawater. Thus the aluminum alloys are adopted in the hull material of hovercraft that is required light in weight as well as high strength. It is very important that the weldability problem of these alloys caused by high thermal conductivities welding deformation, porosity and so on. in this study, auto-welding equipment was applied for aluminum welding automation. Also, optimal welding data were studied by investigating welding characteristics for various shapes of weldment to use Al 5083 that is representative structural materials of the 5000 series of aluminum alloys.

Many tanks such as a fresh water tank, an aft peak tank and oil tanks are arranged in the engine room and aft part areas of the ship. By added mass effect of the fluid inside the tanks, the natural frequency will be changed according to filling height of the tank. For this reason, there is possibility of occurrence of excessive vibration by resonance between natural frequencies of local structure and excitation frequencies of the propeller or main engine. Therefore, calculation of natural frequencies is required for structure for many types of tank which are contacting with water or oil to consider added mass effect for anti-resonance design at design stage. In this study, a case of structure damage on the fresh water tank for 2600 TEU container vessel is introduced. In addition, natural frequency analysis and vibration measurement have been performed to investigate vibration characteristics for excessive vibration control.