• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.309-316
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• 2020

Waterway design should prioritize appropriate channel width to ensure preferential safe passage for the arrival and departure of vessels. To calculate the minimum channel width required for safe passage a comprehensive review of several factors is required. These factors include vessel maneuverability, determined by vessel size, type and speed; environmental factors such as wind, tide, and wave action; human factors, including personal experience and operator judgment as well as marine traffic and navigation support facilities for decision making. However, the Korean channel width design standard is based only on vessel length, and requires improvement when compared with the standards of PIANC, USA, and Japan. This study aims to estimate the appropriate channel width required for one-way traffic in a straight channel, considering various vessel and environmental factors, using Fast Time Simulation (FTS). When the wind speed is 25 knots, with a current speed of 2 knots and a normal vessel speed of 10 knots FTS shows that a 150K GT Cruise Ship requires a minimum channel width of 0.67-0.91 the vessel length (L), whereas a 120K TEU Container Ship and a 300K DWT VLCC require 0.79-1.17 and 1.02-1.59, respectively. Such results can be used to calculate the minimum channel width required for safe passage as an improved Korean design standard.

• Journal of Navigation and Port Research
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• v.35 no.10
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• pp.823-827
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• 2011

The present Common Structural Rules for double hull oil tanker is not included the residual strength, which is one of the functional requirements in design part of Goal-based new ship construction standards (GBS). The GBS will be enforced after July 1, 2016. The requirement related residual strength has the goal to build safe ship even if she has the specified damages due to marine accidents including collision and grounding. In order to assess the residual strength based on risk for structural damages according to GBS, tons of nonlinear FE analysis work taking into account various types of damage will be needed. The Smith's method, a kind of simplified method for the strength analysis is very useful for this purpose. In this paper, the residual strength assessments based on ultimate strength using Smith's method were carried out. The objected ship is VLCC with stranding damage in bottom structures. Also, the results were compared with that of nonlinear FE analysis using three cargo hold model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.552-557
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• 2015

A numerical simulation studies were performed to investigate a manoeuvring characteristics as function of stern hull form with the mathematical model. In order to consider the effect of the stern hull form and obtain the manoeuvring characteristics, a parameter($C_{wa}$) which is aft. water plane area coefficient is modified. Because modifying $C_{wa}$(${\pm}2%$) means that the stern hull form is modified to V-type or U-type, the numerical simulation was performed with this modified $C_{wa}$. A changing trend for the manoeuvring characteristics not only in deep water but also in shallow water such as directional stability, turning and zig-zag was investigated and presented as the results. Present study showed that the manoeuvrability in shallow water largely changed when the draught and water depth ratio(=d/H) become 0.5, and the stern hull form can affect to the manoeuvrability of a vessel navigating in restricted water depth. In addition, it showed that approaching the stern hull to U-type makes the advance and tactical diameter of turning motion large and the overshoot angle of zig-zag motions small. Otherwise, it showed approaching the stern hull form to V-type makes the advance and tactical diameter of turning motion small and the overshoot angle of zig-zag motions large in the present study.

• Korea Trade Review
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• v.48 no.3
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• pp.69-88
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• 2023

This study analyzes the dynamic characteristics of cargo volume (demand), ship fleet (supply), and freight rate (price) of container, dry bulk, and tanker shipping markets by using the VAR and VECM models. This analysis is expected to enhance the statistical understanding of market dynamics, which is perceived by the actual experiences of market participants. The common statistical patterns, which are all shown in the three shipping markets, are as follows: 1) The Granger-causality test reveals that the past increase of fleet variable induces the present decrease of freight rate variable. 2) The impulse-response analysis shows that cargo shock increases the freight rate but fleet shock decreases the freight rate. 3) Among the three cargo, fleet, and freight rate shocks, the freight rate shock is overwhelmingly largest. 4) The comparison of adjR² reveals that the fleet variable is most explained by the endogenous variables, i.e., cargo, fleet, and freight rate in each of shipping markets. 5) The estimation of co-integrating vectors shows that the increase of cargo increases the freight rate but the increase of fleet decreases the freight rate. 6) The estimation of adjustment speed demonstrates that the past-period positive deviation from the long-run equilibrium freight rate induces the decrease of present freight rate.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.467-475
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• 2013

In order to seize quantitative materials as part of studies on measures for oil pollution prevention and control, the statistics of oil pollution incidents in Korean coastal waters for 10 years from 2003 to 2012 were analyzed with relation to the number of oil spills and the volume of oil spilt according to causes, sources and sea areas of spills. Total number and total volume of oil spills for 10 years were found to be 2,833 cases and 17,877 kL, respectively. 50.4 %(1,429 cases) of total number of oil spills were caused by negligence, although oil spillage due to negligence was 294 kL(1.7 %). While oil spillage caused by marine accidents was 17,400 kL(97.3 %), marine accidents accounted for 27.9 %(790 cases) of total number of oil spills. While negligence had a great influence on the number of oil spills, marine accidents had a huge impact on the amount of oil spilt. Fishing boats accounted for 42.7 %(1,210 cases) of the number of oil spills, and although oil tankers accounted for 9.2 %(261 cases) of the number of oil spills, oil spillage from oil tankers was 15,488kL(86.7 %). It means that oil tankers such as VLCC or ULCC may be the main sources of major oil spills and a few very large spills are responsible for a high percentage of the amount of oil spilt. While the number of oil spill incidents was closely related to the accidents of fishing boats, the volume of oil spilt was greatly affected by the major oil spill incidents of oil tankers such as M/T Hebei Spirit. The number and volume of oil spills were shown to be 1,613 cases(56.9 %) and 3,804 kL(21.3 %) in South Sea, 700 cases(24.7 %) and 13,501 kL(75.5 %) in West Sea, and 520 cases(18.2 %) and 572 kL(3.2 %) in East Sea of Korea, respectively. The highest number of oil spills was found in South Sea and the most volume of oil spilt was shown in West Sea of Korea for 10 years.