• International Journal of Naval Architecture and Ocean Engineering
• /
• v.12 no.1
• /
• pp.605-616
• /
• 2020

The construction quality control of hull blocks is of great significance for shipbuilding. The total station device is predominantly employed in traditional applications, but suffers from long measurement time, high labor intensity and scarcity of data points. In this paper, the Terrestrial Laser Scanning (TLS) device is utilized to obtain an efficient and accurate comprehensive construction information of hull blocks. To address the registration problem which is the most important issue in comparing the measurement point cloud and the design model, an automatic registration approach is presented. Furthermore, to compare the data acquired by TLS device and sparse point sets obtained by total station device, a method for key point extraction is introduced. Experimental results indicate that the proposed approach is fast and accurate, and that applying TLS to control the construction quality of hull blocks is reliable and feasible.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.2
• /
• pp.110-119
• /
• 2023

The prediction of ship resistance performance is typically obtained by Computational Fluid Dynamics (CFD) simulations or model tests in towing tank. However, these methods are both costly and time-consuming, so hull-form designers use statistical methods for a quick feed-back during the early design stage. It is well known that results from statistical methods are often less accurate compared to those from CFD simulations or model tests. To overcome this problem, this study suggests a new approach using a Convolution Neural Network (CNN) with voxelized hull-form data. By converting the original Computer Aided Design (CAD) data into three dimensional voxels, the CNN is able to abstract the hull-form data, focusing only on important features. For the verification, suggested method in this study was compared to a parametric method that uses hull parameters such as length overall and block coefficient as inputs. The results showed that the use of voxelized data significantly improves resistance performance prediction accuracy, compared to the parametric approach.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2005.06a
• /
• pp.144-150
• /
• 2005

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.

• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.6
• /
• pp.120-125
• /
• 2004

There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.2
• /
• pp.78-84
• /
• 2008

As a preliminary step to build a complete superyacht hull design program, the development of superyacht profile design system is introduced. The two-dimensional hull profile is decomposed into four local zones depending upon the functionality and connecting continuity of the profile. Characteristics of each zone are investigated and used to generate the model describing the geometric shape of zone using freeform curves. A set of design parameters is derived from the established geometric model. Generation and modification of a model are is by manipulating the chosen parameters. Four zones designed are integrated to form a final profile. An interactive design system performing all the modeling and modification processes is implemented using the graphic user interface system based an Microsoft Foundation Class and OpenCASCADE, a open graphic library. The shapes of the profiles generated by the developed design system are verified with those of built superyachts. The developed design system will be used for the construction of three-dimensional superyacht hull modeling system.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.5
• /
• pp.502-512
• /
• 2008

CFD tools were intensively used to develop a bulk carrier hull form of 180,000 DWT. HCAD and WAVIS were utilized to vary and evaluate the hull forms. LCB and framelines were systematically changed starting from a mothership. Resistance characteristics have been assessed by evaluating the wave-pattern resistance and viscous pressure drag along with the wave profile and wake distribution. It was found that the hull forms obtained from LCB variations were not good enough to satisfy the target resistance coefficient because of large wave generation at the design speed. After choosing the appropriate one from the LCB variation series, bow and stern framelines have been modified to improve wave-making characteristics and wake distribution, respectively. Model tests were performed to confirm the CFD results. Furthermore, the effect of free surface on CFD application was investigated, and a few comments are given on the difference between WAVIS version 1.4 and 2.0.

• Journal of the Society of Naval Architects of Korea
• /
• v.38 no.3
• /
• pp.14-22
• /
• 2001

This paper presents the results of hull form design and powering performance for a 2.500 ton class trimaran frigate. A series of resistance tests and numerical calculations have been conducted to figure out the influences of side-hull form and position on the resistance characteristics of the trimaran. And the propulsion test was conducted to investigate the propulsion efficiency of the trimaran, and the powering performance of the trimaran was compared with that of the similar mono-hull ships in full scale. From the research it was found that the longitudinal position of side-hull had a large influence on the resistance characteristics of the trimaran while the side-hull form and transverse position had a small influence on it. The trimaran showed favorable resistance performance when the side-hull was located near the stern of trimaran, which was resulted from the fact that the side-hull stem was located near the primary wave hollow generated by the main hul1. The powering performance of the trimaran was superior to that of the similar mono-hull ships above the middle speed range.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.6
• /
• pp.405-410
• /
• 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 Society of Naval Architects of Korea
• /
• v.49 no.2
• /
• pp.182-188
• /
• 2012

The hull form design technique for high speed power boat based on the parametric design method is presented in this paper. While the design methods of conventional vessels that are currently in use have been well developed in various aspects from existing database. However, an easy and simple design program for high speed power boats needs to be provided for the relatively small boat builders who are in lack of experience and skilled manpower. This paper presents a parametric design technique which is aimed to provide an easier creation of a new model by inputting several parameters, such as angles and lengths, which correlate with hydrodynamics characteristic for high speed boats. The paper also introduces the prototype program developed to design power boat with parametric design technique.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.5
• /
• pp.558-570
• /
• 2015

A study on the green ship design for Ultra Large Container Ship (ULCS, 18,000 TEU Class Container Ship) was performed based on the four step procedures of the initial design and hull form optimization to maximize economic and propulsive performance. The first, the design procedure for ULCS was surveyed with economic evaluation considering environmental rules and regulations. The second, the characteristics of single and twin skeg container ships were investigated in view of initial design and performances. The third, the hull form optimization for single and twin skeg ships with the same dimensions was conducted to improve the resistance and propulsive performances at design draught and speed by several variations and the results of the optimization were verified by numerical calculations of CFD and model test. The last, for the estimated operating profile of draught and speed, the hull forms of single and twin sked ships were optimized by CFD. From this study, the methodologies to optimize the hull form of ULCS were proposed with considerations during the green ship design and the improvement of the energy efficiency for the optimized hull forms was confirmed by the proposed formula of the total energy considering design conditions, operating profile and fuel oil consumption.