• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.2
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• pp.136-143
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• 2013

The analysis of the written verdicts in recent five years was conducted to obtain preventive measures of collision between fishing vessel and non fishing vessel. As a result, a collision much happened in offshore trap for fishing vessel and below 5,000 tons of small and medium class for non fishing vessel. A person involved in a marine accident occupied 68% in sixth class deck officer and small boat operator for fishing vessel and 29% in third class deck officer for non fishing vessel. 90% of the collision happened in a underway by operating state and 84% in sight of one another by visibility state. The systemic radar training was required since 47% of the collisions was occurred on the condition of radar operation in fishing vessel. The main cause of poor lookout was a intensive fishing and poor lookout on movement by radar for fishing vessel and one man watch system and no recognition of one another by radar for non fishing vessel. This result is expected to contribute for the decrease of collision.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.119-125
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• 2007

In recent days, the consumption of stainless steel in the propulsion shafting systems for small-medium class vessel is increased due to its high corrosion protection with wear resistant properties. Unfortunately the small and medium class vessel that operated in the west-south sea area of Korean peninsula experienced heavy wear down due to the role of mud. In the event of wear or broken down, the propeller shaft must be replaced by new one, but the new shaft is very expensive and time-consuming for order made supply. In this case, the methods of built up for wear and broken shaft by welding is one of the most effective cases. In this study, the built up welding for austenitic stainless steel shaft has been accomplished by various pre-surface treatment, welding methods, post heattreatment and inspection. The results confirmed that the built-up welding was one of the effective methods for stainless steel shafting.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.791-798
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• 2016

In this study, numerical simulations on the effects of bilge keel on roll motion were conducted. The numerical simulations were performed on a 110 m class PSV using the commercial viscous flow analysis software Star-CCM+. Before conducting the study on the 110 m class PSV, an additional simulation of DTMB 5512 was performed and compared with the experimental results to validate the feasibility of the numerical simulation. In the simulation on PSV, a nondimensional damping coefficient was calculated using a free roll decay simulation, and the response amplitude operator (RAO) for the roll motion was calculated with a nondimensional damping coefficient at two conditions (with/without bilge keel).

• Composites Research
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• v.35 no.5
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• pp.347-358
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• 2022

Carbon fiber is an excellent structural material, which has been proven in many industries, and the shipbuilding industry is no exception. In particular, in advanced maritime countries, special ships of the Navy and Coast Guard with carbon fiber composite hulls have already been deployed. In Korea, carbon fiber composite materials have been applied to a 10-ton class leisure craft or a 30-ton class patrol, but no research has been done on a hundred of tons or more vessels. In this study, the feasibility study of a 500-ton patrol vessel with a carbon fiber composite hull was conducted through an analysis of similar cases abroad. As a result, it was recognized that the developed hull can be reduced in weight by about 21% to 25% compared to the existing aluminum or FRP hull. It was also confirmed that this light-weight effect can induce the improvement of the maximum speed and the improvement of the operating range via simulations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.365-372
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• 2024

The South Korean marine industry is emerging as a significant market, driven by the growing popularity of various water leisure activities, including sailing. This trend suggests a rising demand for sailing yachts. Consequently, since 2022, the design and development of a 28ft sailing yacht have been ongoing, supported by the government and the Ministry of Oceans and Fisheries, to promote yachting culture in South Korea. The Velocity Prediction Program (VPP) analysis was conducted using WinDesign during the preliminary design stage to evaluate performance and determine design parameters. The hydrodynamic model used for this vessel is based on regression methods developed from years of experience in naval architecture and yacht research at the Wolfson Unit, providing reliable estimates for most modern yachts. However, owing to the lack of specific hydrodynamic data from towing tank tests or CFD numerical analysis, verification of the hydrodynamic model has faced some challenges. Additionally, an incomplete weight estimate resulted in variable VCG values, potentially affecting stability and overall performance. The optimal boat speed for this vessel was determined at true wind speeds (TWS) of 4, 8, 12, 16, and 20 knots, using both the jib (up to 120° TWA) and the spinnaker (from 80° TWA). The optimized speed of the yacht was found to be comparable to that of international similar-class yachts.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.367-375
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• 2012

In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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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.