• 한국항해항만학회지
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• 제43권5호
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• pp.310-319
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• 2019

With the recent increase in the volume of liquid cargo transportation, there is a need for STS( Ship To Ship) globally. In the case of the STS mooring, the safety assessment should be conducted according to other criteria because mooring is different from the general mooring at the quay, but there is no separate standard in Korea. Thus in this study, STS mooring simulation and sensitivity analysis using OPTIMOOR program, the numerical analysis program, was conducted to identify the characteristics of the STS mooring. The target sea modeled the Yeosu port anchorage in Korea and the target ship was selected as the case of VLCC (Very Large Crude Oil Carrier)-VLCC. Through the numerical simulation and sensitivity analysis, the characteristics of STS mooring were identified. Also based on these results, we focused on establishing the standard for STS mooring safety assessment. Numerical simulation results show that the STS mooring safety can be changed according to a ship's cargo loading condition, pre-tension of mooring line, sea depth, encounter angle with the weather, and the weather condition. Additionally, the risk matrix is prepared to establish the safe external force range in the corresponding sea area. This result can be used to understand the mooring characteristics of STS and contribute to the revision of mooring safety assessment criteria.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 춘계학술대회
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• pp.135-137
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• 2019

최근 액체화물운반선 운송량이 증가함에 따라 국내외에서 해상환적(Ship-to-ship)에 대한 필요성이 대두되고 있다. STS 계류의 경우, 일반적인 부두에서의 계류와 그 특성이 다르기 때문에 다른 기준으로 안전성 검토가 이루어져야 하지만, 국내에서는 별도의 기준이 부재한 상황이다. 따라서 본 연구에서는 STS계류의 특성을 파악하기 위해 상용 수치해석프로그램인 OPTIMOOR 프로그램 이용한 STS 계류 시뮬레이션 및 민감도 분석을 시행하였다. 대상해역은 여수항의 D2 정박지를 모델링하였으며, 대상 선박의 모델링은 VLCC-VLCC의 Case로 선정하였다. 이 수치해석과 민감도 분석을 통하여 STS 계류의 특성을 파악하고자 하였으며 이를 바탕으로 STS 계류안전성 평가에 대한 기준을 확립하고자 하였다. 수치해석 시뮬레이션 결과, STS 계류는 선박 재화상태, 기상상태(파주기 및 파고영향) 및 만남각, 그리고 계류삭의 초기장력 등에 따라 변화함을 확인하였다. 또한 Risk Matrix를 작성하여 해당 해역에서의 안전외력범위를 설정하였다. 이 결과를 통해 STS의 계류 특성을 파악할 수 있으며, 계류안전성 평가 기준을 개정에 기여할 수 있을 것으로 기대한다.

• 한국항해항만학회지
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• 제38권6호
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• pp.577-583
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• 2014

A ship-to-ship (STS) lightering operation takes place in order to transfer cargo (e.g. crude oil or petroleum products) between an ocean-going ship and a service ship alongside it. Instrumental measurements to accurately determine the relative speeds and distances during the approach between the vessels would benefit the operational safety and efficiency. A velocity information GPS (VI-GPS) system, which uses the instantaneous velocity measures from carrier-phase Doppler measurement, has been applied in a field observation onboard a service ship (Aframax tanker) approaching a ship-to-be-lightered (VLCC) in open waters. This article proposes to apply VI-GPS as the input sensor to a guidance and decision-support system aiming to provide accurate velocity information to the officer in charge of an STS operation. A method for precise velocity measurement using VI-GPS was described and the measurement results were compared each other with the results of Voyage Data Recorder (VDR) and VI-GPS that showed the concept of a guidance and decision-support system applying VI-GPS with the field test results during STS operations. Also, it turned out that VI-GPS has sufficient accuracy to serve as an input sensor from the field test results.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 추계학술발표회
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• pp.186-186
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• 2017

• 해양환경안전학회지
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• 제24권3호
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• pp.352-359
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• 2018

As a fuel for ship propulsion, liquefied natural gas (LNG) is currently considered a proven and reasonable solution for meeting the IMO emission regulations, with gas engines for the LNG-fueled ship covering a broad range of power outputs. For an LNG-fueled ship, the LNG bunkering process is different from the HFO bunkering process, in the sense that the cryogenic liquid transfer generates a considerable amount of boil-off gas (BOG). This study investigated the effect of the temperature difference on boil-off gas (BOG) production during ship-to-ship (STS) LNG bunkering to the receiving tank of the LNG-fueled ship. A concept design was resumed for the cargo/fuel tanks in the LNG bunkering vessel and the receiving vessel, as well as for LNG handling systems. Subsequently, the storage tank capacities of the LNG were $4,500m^3$ for the bunkering vessel and $700m^3$ for the receiving vessel. Process dynamic simulations by Aspen HYSYS were performed under several bunkering scenarios, which demonstrated that the boil-off gas and resulting pressure buildup in the receiving vessel were mainly determined by the temperature difference between bunkering and the receiving tank, pressure of the receiving tank, and amount of remaining LNG.

• 선박안전
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• 통권24호
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• pp.4-20
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• 2008

Stainless steel 304 or stainless steel 630 types using propeller shaft of a small ship or a FRP fishing boat generally restrain localization corrosion and abrasion damage occurrence to shaft bearing or grand packing contact. In general, the residual stress which remains after welding or heat treatment in material can cause the stress concentration or localization corrosion. In case of small ship, stainless steel such as STS304 has long been used for propeller shaft. Meanwhile, crew of small ship tend to reuse damaged propeller shaft after repair by welding and performing heat treatment to save cost. However, it was found that reused propeller shaft by repair often caused troubles in ship's operation. In this study, the basic guideline for maintenance and treatment of propeller shaft are investigated. From the results of investigation, remarkable deterioration of the material properties and corrosion resistance on the welded work part was observed.

• 해양환경안전학회지
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• 제28권5호
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• pp.809-818
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• 2022

국제해사기구(IMO)의 대기오염물질 배출 규제에 대응하기 위해 액화천연가스(LNG)를 연료로 사용하는 선박이 증가하고 있다. 이와 함께 선박의 안정적인 연료 수급을 위한 LNG 벙커링 인프라 확대의 필요성이 대두되고 있다. LNG 벙커링은 TTS(Truck to ship), PTS(Pipe to ship), STS(Ship to ship) 3가지 방식으로 진행된다. 외국에서는 3가지 방식 모두 진행하고 있지만, 국내의 경우 인프라 부족으로 TTS 방식으로만 LNG 벙커링이 진행되고 있다. LNG 벙커링은 위험 요소가 많은 작업으로 안전한 벙커링 작업을 위해 작업 종사자의 역량이 아주 중요하며 역량 강화를 위한 전문교육과정이 필요하다. 본 연구는 LNG 벙커링 전문인력 육성과 안전하고 체계적인 벙커링 작업수행을 목적으로 LNG 벙커링 종사자 교육 콘텐츠를 설계하기 위해 진행되었다. 이를 위해 LNG 연료추진선박 및 벙커링 현황을 파악하고 국내외 관련 교육내용을 분석하였다. 더불어 전문가 설문을 통해 교육내용의 중요성에 대한 의견을 수렴하였다. 연구의 결과로서 다양한 교육 대상에 적합한 교육 콘텐츠 설계를 하고, 이를 총 4일이 소요되는 기초교육과 상급교육 과정으로 구분하여 제안하였다. 설계된 교육 콘텐츠를 바탕으로 우리나라 벙커링 환경을 충분히 반영하여 추가 연구가 진행된다면 LNG 벙커링 종사자 역량 증진을 도모하고 인적 자원 육성에 큰 도움이 될 것으로 사료 된다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권6호
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• pp.698-703
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• 2014

최근 기존 화석연료의 고갈로 인하여 대체에너지로써 천연액화가스의 수요 증가와 함께 LNG 운반선의 수요가 증가하고 있으며, 그로인해 극한의 환경에서 사용할 수 있는 LNG 선박용 벨로우즈의 수요 또한 증가할 것으로 예상된다. 현재 LNG 선박용 벨로우즈에 사용되는 재료는 저온취성과 해수부식에 강한 INCOLOY 825와 STS316L합금이다. 본 연구에서는 극저온에 사용되는 LNG용 벨로우즈 재질인 INCOLOY 825과 STS316L 합금에 대하여 최적의 용접조건을 설정하고, 에릭센 시험을 통하여 용접부의 성형성을 분석하였다. 최적 조건에서의 용접시 용접부의 인장강도는 모재에 비하여 90% 이상의 강도값을 나타내었다. 또한 에릭센 시험을 통한 성형성 분석의 결과, 용접부가 아닌 모재에서 파단이 발생하는 매우 양호한 용접부를 얻을 수 있었다.

• 선박안전
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• 통권22호
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• pp.34-53
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• 2007

In the case of hull material. large sized merchant ships are made of steel, on the other hand FRP or wood are used for small sized fishing boats. At present in Korea approximately 88,500 fishing boats are in operation of which 70% are made of FRP In the meantime, stainless steel is frequently used as shaft materials of the small-size FRP fishing boat. Namely, the kinds of shaft materials are STS 304(18Cr-8Ni), STS 316(18Cr-12Ni-2.5Mo steel) and STS 630(17Cr-Ni-Nb steel)etc. Among these things, STS 304 which is the cheapest and having ordinary corrosion resistance is most widely used as 2nd class shaft material. But, using STS 304 for shaft system material of the small-size FRP fishing boat on seawater environments entails a severe corrosion which causes shaft system troubles. Particularly, the corrosions tend to be concentrated of the stern and bow side, propeller shaft surface of inside of stern tube and the boat having no stern cooling pipe line system. As a solution for those problems, research on the ways to mitigate corrosion on the part of 2nd class stainless steel shaft have been undertaken. In the result, not only clarification for the reason of corrosion of the part of stainless steel shaft used mainly for the small-size FRP fishing boat was done, but also most optimal corrosion protection system was developed by experimenting shaft's protection simulation based of the electrochemical cathodic protection principle. In addition, verification through the field test on the optimal cathodic corrosion protection method by means of aluminum sacrificial anode was carried out. In this study, effective and economical shaft's protection system is suggested to the small-size FRP fishing boat operator by substantiating the results obtained from the research on the optimal cathodic protection.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.217-227
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• 2004

The bowl in a ship purifier suffers from high stress and high temperature in a detrimental heavy fuel oil environment. Duplex stainless steel(DSS) is a primary material to withstand this harsh condition. Newly-manufactured STS 329 grade DSS has been evaluated by various mechanical and electrochemical test methods. Eight heat treatment(HT) conditions with different temperature and time were applied to the DSS samples to improve corrosion resistance. Microstructure and polarization test results concluded the optimum HT condition was $1.090^{\circ}C$-60 minutes. Confirmation experiments for applying to a real bowl including stress corrosion cracking test exhibited the reproducibility of the optimum HT condition.