• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.176-183
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• 2024

Assessing the stability of small fishing vessels is important to prevent capsize accidents in coastal waters that primarily occur on small fishing vessels. However, the regulations regarding stability assessment for small vessels under 24 m are inadequate according to the domestic Fisheries Act. Based on safety standards issued by the Ministry of Oceans and Fisheries in 2022 to enhance safety and welfare, vessels adhering to the enhanced safety standards for standard ship types are required to establish stability regardless of their length. This study aims to utilize these aforementioned standards to assess the stability of vessels under 24 m, investigating the suitability of applying these criteria to these vessels and examining the impact on various small vessels with different superstructures. Initially, a 4.99-ton fishing vessel designed according to the standard ship type was selected as the subject vessel. Compliance with the standards was evaluated based on the initial stability of the vessel using the transverse metacentric height (GM) and transverse restoring moment arm at the limit angle (GZ_α). Additionally, six types of small vessels with identical hull forms and specifications to the subject vessel were further examined using prevalent superstructure designs in small fishing vessels. The stability of the subject small vessel was also assessed. A study of a 4.99-ton standard fishing vessel confirmed that the safety standards for standard fishing vessels with enhanced safety welfare were applicable to small fishing vessels under 4.99-ton class and that the stability of small fishing vessels with superstructure modifications was not significantly changed.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.161-172
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• 2024

Approximately 89% of all capsizing accidents involve small vessels, and despite their relatively high accident rates, small vessels are not subject to ship stability regulations. Small vessels, where the provision of essential basic design documents for stability calculations is omitted, face challenges in directly calculating their stability. In this study, considering that the majority of domestic coastal small vessels are of the Chine-type design, the goal is to establish the major hull form characteristic data of vessels, which can be identified from design documents such as the general arrangement drawing, as input data. Through the application of a deep learning approach, specifically a multilayer neural network structure, we aim to infer hydrostatic curves, operational draft ranges, and more. The ultimate goal is to confirm the possibility of directly calculating the initial stability of small vessels.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.199-212
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• 2020

A large percentage of maritime accidents in coastal seas are related to small fishing vessels. In order to investigate causes of maritime accidents, it is often necessary to carry out dynamic simulations for the estimation of trajectories and motions of vessels. Initial conditions of vessels such as main dimensions, loading conditions and hydrostatic properties are required for the accurate simulations. Small fishing vessels usually have few records of hydrostatic properties during their fishing operations. Therefore, in this study, estimation procedures for hydrostatic properties of small fishing vessels are proposed. At first, hull form characteristics of Korean small fishing vessels are investigated. Most of vessels have hard-chines and centerline skegs, they have similar hull forms. Bonjean curves of several small fishing vessels whose gross tonnages are below 10 tons are normalized with vessel breadths and depths. Representative bonjean curves are derived from normalized bonjean curves, and a representative hull plan is obtained as well. If the vessel loading conditions such as total weights and centers of gravity are given, fore and aft drafts can be calculated by using the representative bonjean curves with the constraint that weights and buoyancies are in equilibrium. Metacentric heights are also estimated by using the representative hull plan. Drafts and metacentric heights estimated by proposed iterative estimation procedures are compared with actual vessel data, estimated values are in good agreements with actual values. In addition, normalized fore and aft drafts, metacentric heights of vessels can be formulated as the linear functions of normalized total weights and centers of gravity. Empirical formulas of drafts and metacentric heights are proposed, and it is confirmed that the empirical formulas also provide reasonable results, which are similar to the results by iterative estimation procedures with representative bonjean curves and hull plan.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.51-63
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• 2005

In relation with inspection systems of small fishing vessels, Government is drawing up revision of the law about ships safety act(Article 3) on the basis of supporting safe fishing activities to expand the application range of ships safety act for vessels under 2 tons(small fishing vessels) that are exempted from inspection systems. There are two opinions about inspection of small fishing vessels. Government's opinion is that inspection of small fishing vessels must be enforced to confirm small fishing vessels' safety but fishermen's opinion is that inspection systems keep on existing law because inspection systems spends a lot of time and money to the poor and the old. The alternatives for countered opinions is that the poor fishermen's vessels' for living or small vessels' inspection must be operated by themselves in principle and minimizing the limitation through policies is recommended. In addition, Government needs to develop various programs for inspection systems of small fishing vessels like the main fisheries countries. Particularly, in case of operating inspection systems of small fishing vessels, Government needs to consider some solutions for example supporting inspection fee, minimum inspection for confirming vessels' safety, inspecting when a vessel is building, expanding an inspection period.

• Toxicological Research
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• v.34 no.4
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• pp.363-370
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• 2018

Many studies reported reduced antioxidant capacity in the vasculature under hypertensive conditions. However, little is known about the effects of antihypertensive treatments on the regulation of vascular antioxidant enzymes. Thus, we hypothesized that antihypertensive treatments prevent the reduction of antioxidant enzyme activity and expression in the small vessels of angiotensin II-induced hypertensive rats (ANG). We observed the small mesenteric arteries and small renal vessels of normotensive rats (NORM), ANG, and ANG treated with a triple antihypertensive therapy of reserpine, hydrochlorothiazide, and hydralazine (ANG + TTx). Systolic blood pressure was increased in ANG, which was attenuated by 2 weeks of triple therapy (127, 191, and 143 mmHg for NORM, ANG, and ANG + TTx, respectively; p < 0.05). Total superoxide dismutase (SOD) activity in the small mesenteric arteries of ANG was lower than that of NORM. The protein expression of SOD1 was lower in ANG than in NORM, whereas SOD2 and SOD3 expression was not different between the groups. Reduced SOD activity and SOD1 expression in ANG was not restored in ANG + TTx. Both SOD activity and SOD isoform expression in the small renal vessels of ANG were not different from those of NORM. Interestingly, SOD activity in the small renal vessels was reduced by TTx. Between groups, there was no difference in catalase activity or expression in both the small mesenteric arteries and small renal vessels. In conclusion, SOD activity in the small mesenteric arteries decreased by angiotensin II administration, but not by hypertension, which is caused by decreased SOD1 expression.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.373-380
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• 2018

The small coastal vessel registered in Korea, small coastal vessels with a gross tonnage of 10 tons or less account for 94.6 % and among them, aged vessels over 16 years age indicate 40.6 %. In order to reduce GHG emissions from small coast vessels, discussions are underway to replace aging ships' propulsion units with eco - friendly propulsion facilities, and the electric propulsion ship is emerging as one of the measures. The electric propulsion system using the DFE rectifier, which was applied in the conventional large commercial vessel, was effective in reducing the harmonics and improving the DC output voltage of the DC link stage, but it occupied a large volume and caused an increase in the overall system price. Therefore, in this paper, we propose an electric propulsion system using AFE rectifier with a small volume of system that can be applied to a small coastal vessel. In order to analyze the effectiveness of the overall system, the load profile was applied to obtain accurate and rapid speed tracking performance of the propulsion motor affected by the speed load. In addition, the power factor and total harmonic distortion factor of the voltage and current on the improved power output side are derived through simulation.

• Journal of Korea Ship Safrty Technology Authority
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• s.22
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• pp.19-33
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• 2007

According to amendments of ship safety act which comes into force from 4 Nov. 2007, the amended stability criteria should be applied to the small vessels of 12m or more in length. In this paper, the dimensions of domestic small vessels and the casualty reports of capsizing accidents are analyzed. And 58 ships are sampled, modeled for the investigation of the stability performance. Based on the regression analysis of the model ship's allowable metacentric-heights under several stability requirements, stability criteria for small fishing vessels and cargo ships are proposed.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.3 s.153
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• pp.285-295
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• 2007

In order to ensure safety of small vessels, the amended Ship Safety Act will come into force on 4th. Nov. 2007. This study is performed to suggest the stability criteria of fishing vessels and cargo ships of 12m in length and over but less than 24m in length which will be new object of amended Ship Safety Act. We have analyze the dimensions of domestic small vessels and the casualty reports of capsizing accidents. According to the analyzed result, 58 ships that are in the range of the dimension are modeled and the stability calculation has been carried out. The Stability for the 58 ships has been analyzed by comparing the result that applied the selected standard in the national standard to the stability calculation. Based on the regression analysis of the model ship's allowable transverse metacentric-heights under several stability requirements, stability criteria for small fishing vessels and cargo ships are proposed.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.125-126
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• 2006

This document summarizes the work completed during the interessional period by the IMO SLF correspondence group on the drafting of Safety standards for small fishing vessels, which was established at IMO SLF 48.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.875-888
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• 2018

The Government of the Republic of Korea has been continuously improving its legal system to ensure marine safety as a precaution against marine accidents. However, despite the ongoing improvement of the legal system, the number of maritime accidents has been increasing steadily, suggesting that the efficacy of the legal system is insufficient. As for recent marine accidents, small fishing vessels (less than 10 tons) account for 44.9 % of marine accidents over 5 years ('13_'17). Therefore, this study investigated the improvement status of the Korean government's legal system for small fishing vessels and the characteristics of related overseas legal systems in order to find a way to further improve marine safety for small fishing vessels. Following the results, the Korean government's laws related to small fishing vessels show a hybrid phenomenon due to the history of merging ('97) and separation ('09) of legal systems for fishing and non-fishing vessels, and it has been concluded that only improvements to construct additional facilities are being performed, and those in a fragmentary manner. In addition, overseas legal systems for small fishing vessels were confirmed to have requirements strengthening the responsibility of owners and operators of fishing vessels and introduced a self-inspection program. Based on these results, a plan is suggested to improve the efficacy of the legal system to ensuree marine safety for small Korean fishing vessels.