A Study on Improvement of Criteria for Mooring Safety Assessment in Single Point Mooring

Sang-Won Lee,Young-Du Kim 해양환경안전학회 2019 海洋環境安全學會誌 Vol.25 No.3

The recent increase in crude oil trading has led to an increase in the workings of SPM for crude oil carriers. VLCCs generally encounter difficulty entering port due to limitations in terms of sea depth and maneuverability. The SPM is a system that allows mooring to the buoy located in the outer sea for such vessels. However, the buoy is more affected by relatively external forces because of their offshore location. Therefore, the safety assessment of SPM is particularly important as it can lead to large oil pollution disasters in the event of SPM accidents. Despite this, in the implementation of the Marine Traffic Safety Audit Scheme in Korea, there exists no guidance for SPM. In this study, a SPM mooring safety assessment is performed using OPTIMOOR, a numerical analysis program, so as to understand the mooring characteristics of SPM. As a result, it is confirmed that the tension of mooring lines and hull movement in the SPM are greatly affected by the encounter angles with external forces. In addition, it is found that the maximum tension of the mooring line is elevated as the water depth becomes shallower through sensitivity analysis. According to SPM characteristics, which has a large influence on the encounter angle, this study has proposed an amendment to setting criteria in the implementation of the Maritime Traffic Safety Audit Scheme which could improve the reliability and accuracy of mooring safety assessments.

Identification of Impact Factors in Ship-to-Ship Mooring Through Sensitivity Analysis

Sang-Won Lee,Hyeong-Tak Lee,Dae-Gun Kim,Ik-Soon Cho 한국항해항만학회 2019 한국항해항만학회지 Vol.43 No.5

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.

여객선 부두 계류안전성 평가를 통한 계류 환경 개선에 관한 연구

김대근,강은지,조익순 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.2

Most of the domestic car ferries departing from Jeju Port in Korea were replaced through the construction of new ships or the introduction of new used ships starting in 2018 after the Sewol Ferry accident. Amid this trend of ship replacement, the size of passenger ship has also become larger than in the past to increase passenger sales and cargo transportation profits, but the passenger ship berth configuration at Jeju Port have not improved significantly. In this study, the current status of passenger ships at Jeju Port was investigated, and a mooring safety assessment was conducted on car ferries exceeding the design berth capacity of the pier. Risk factors of the target ship were identified through mooring safety assessment. Through the sensitivity analysis of each improvement plan, a plan to improve mooring configuration was proposed and its effect was confirmed. As a result, the in case of Arion Jeju which is berthed at No. 2 pier, improvement plan scenario case 1 to 4 from the operator’s perspective did not secure the mooring safety due to the problem of exceeding maximum traction force with the size of the mooring post. However in case of scenario case 5 of the improvement plan through the additional installation of High Height Bitt, it was analyzed that a load of about 23% or less of the breaking strength of all lines acts on the mooring line and the load of 44% or less of the maximum traction force of the mooring post acts that the mooring safety was evaluated to be secured. The results of this study are expected to be used as reference materials for the establishment of safe passenger ship berth mooring configuration and the development of guidelines for mooring a car ferry.

A Study on Improvement of Criteria for Mooring Safety Assessment in Single Point Mooring

Lee, Sang-Won,Kim, Young-Du The Korean Society of Marine Environment and safet 2019 海洋環境安全學會誌 Vol.25 No.3

The recent increase in crude oil trading has led to an increase in the workings of SPM for crude oil carriers. VLCCs generally encounter difficulty entering port due to limitations in terms of sea depth and maneuverability. The SPM is a system that allows mooring to the buoy located in the outer sea for such vessels. However, the buoy is more affected by relatively external forces because of their of shore location. Therefore, the safety assessment of SPM is particularly important as it can lead to large oil pollution disasters in the event of SPM accidents. Despite this, in the implementation of the Marine Traffic Safety Audit Scheme in Korea, there exists no guidance for SPM. In this study, a SPM mooring safety assessment is performed using OPTIMOOR, a numerical analysis program, so as to understand the mooring characteristics of SPM. As a result, it is confirmed that the tension of mooring lines and hull movement in the SPM are greatly affected by the encounter angles with external forces. In addition, it is found that the maximum tension of the mooring line is elevated as the water depth becomes shallower through sensitivity analysis. According to SPM characteristics, which has a large influence on the encounter angle, this study has proposed an amendment to setting criteria in the implementation of the Maritime Traffic Safety Audit Scheme which could improve the reliability and accuracy of mooring safety assessments.

A Study on Improvement of Criteria for Mooring Safety Assessment in Single Point Mooring

이상원,김영두 해양환경안전학회 2019 海洋環境安全學會誌 Vol.25 No.3

The recent increase in crude oil trading has led to an increase in the workings of SPM for crude oil carriers. VLCCs generally encounter difficulty entering port due to limitations in terms of sea depth and maneuverability. The SPM is a system that allows mooring to the buoy located in the outer sea for such vessels. However, the buoy is more affected by relatively external forces because of their offshore location. Therefore, the safety assessment of SPM is particularly important as it can lead to large oil pollution disasters in the event of SPM accidents. Despite this, in the implementation of the Marine Traffic Safety Audit Scheme in Korea, there exists no guidance for SPM. In this study, a SPM mooring safety assessment is performed using OPTIMOOR, a numerical analysis program, so as to understand the mooring characteristics of SPM. As a result, it is confirmed that the tension of mooring lines and hull movement in the SPM are greatly affected by the encounter angles with external forces. In addition, it is found that the maximum tension of the mooring line is elevated as the water depth becomes shallower through sensitivity analysis. According to SPM characteristics, which has a large influence on the encounter angle, this study has proposed an amendment to setting criteria in the implementation of the Maritime Traffic Safety Audit Scheme which could improve the reliability and accuracy of mooring safety assessments.

Identification of Impact Factors in Ship-to-Ship Mooring Through Sensitivity Analysis

Lee, Sang-Won,Lee, Hyeong-Tak,Kim, Dae-Gun,Cho, Ik-Soon Korean Institute of Navigation and Port Research 2019 한국항해항만학회지 Vol.43 No.5

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.

Identification of Impact Factors in Ship-to-Ship Mooring Through Sensitivity Analysis

이상원,이형탁,김대근,조익순 한국항해항만학회 2019 한국항해항만학회지 Vol.43 No.5

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.

A Study on the Allowable Range of Overhanging Berthing at the Port of Ulsan

Seungyeon Kim,Yongung Yu,Yunsok Lee 해양환경안전학회 2019 海洋環境安全學會誌 Vol.25 No.3

As vessels become larger and competition between ports intensifies, there has been an increase in the number of cases where vessels that exceed the available berths are berthed at the pier. Therefore, there has been an increase in the number of cases in which the bow or stern of a ship is projected and moored. The risk of overhanging berthing is that mooring safety can be compromised because it is not possible to connect the bow and stern mooring line to the ship properly. In addition, collision accidents may occur between moving vessels if the view of a vessel moving in the port is obstructed. Therefore, in this study, the simulation of mooring safety was performed according to the overhanging range in Piers No. 6 and 7 in Ulsan’s main port to propose the overhanging limit and operational standards according to each ship. As a result of the assessment, 30,000 DWT bulkers are able to overhang up to 0.75B, and 50,000 DWT bulkers can overhang up to 0.50B. The results of this study are expected to be used as basic data for setting the allowable overhang limit, as well as clear usage criteria for safe unloading operations.

항로 인접 계류선의 안전 확보를 위한 통과선의 항행기준 분석

임민정(Min-Jeong Lim),조익순(Ik-Soon Cho) 한국연안방재학회 2023 한국연안방재학회지 Vol.10 No.3

The ship wave generated by the passing ship can affect to the nearby berth and moored vessels. This can result in excessive motion of the moored ship and lead to the severing of mooring lines, potentially causing accidents. The aim of this study is to analyze the effect of passing ships navigating through the vicinity of the berth, evaluate the risks posed to the safety of moored ship, and propose safety measures. The OPTIMOOR analysis software was utilized for the assessment, with Berth A in Ulsan Port chosen as the target. The study revealed that the speed of passing ships and the separation distance between vessels significantly influence the motion of moored ships. Considering the high-risk of Berth A due to its proximity to the fairway, proposed navigation criteria for the Ulsan Port's No.1 fairway to ensure mooring safety. It has been determined that passing ships in the vicinity of Berth A should maintain a proper speed less than 8 knots, or navigate at a distance of more than 200 meters away from the dock. This study can contribute to decision-making and the establishment of safety measures in berth and fairway design.

A Study on the Allowable Range of Overhanging Berthing at the Port of Ulsan

Kim, Seungyeon,Yu, Yongung,Lee, Yunsok The Korean Society of Marine Environment and safet 2019 海洋環境安全學會誌 Vol.25 No.3

As vessels become larger and competition between ports intensifies, there has been an increase in the number of cases where vessels that exceed the available berths are berthed at the pier. Therefore, there has been an increase in the number of cases in which the bow or stern of a ship is projected and moored. The risk of overhanging berthing is that mooring safety can be compromised because it is not possible to connect the bow and stern mooring line to the ship properly. In addition, collision accidents may occur between moving vessels if the view of a vessel moving in the port is obstructed. Therefore, in this study, the simulation of mooring safety was performed according to the overhanging range in Piers No. 6 and 7 in Ulsan's main port to propose the overhanging limit and operational standards according to each ship. As a result of the assessment, 30,000 DWT bulkers are able to overhang up to 0.75B, and 50,000 DWT bulkers can overhang up to 0.50B. The results of this study are expected to be used as basic data for setting the allowable overhang limit, as well as clear usage criteria for safe unloading operations.