• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.487-494
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• 2010

In order to test the applicability of bunker-A in a diesel engine for small-fishing boat, the investigation of the engine performance and the exhaust emission was performed under various conditions of fuel property, intake air pressure and fuel temperature. It was also performed based on IMO NOx Technical code. At high load, the energy consumption rate of bunker-A was lower than that of diesel oil, and the characteristics of exhaust emission of bunker-A were similar to those, and NOx emission rates of both fuels satisfied the IMO NOx emission regulation limits. The energy consumption rate and characteristics of exhaust emission were improved as the intake air pressure was increased, but these were not improved remarkably as the temperature of bunker-A was heated. However, at low load the energy consumption rate, CO emission rate and HC emission rate of bunker-A were higher than those of diesel oil, but NOx emission rates of the fuels were about the same. In addition, at low load the energy consumption rate and CO emission rate of bunker-A were increased as the intake air pressure and the temperature were higher than normal conditions. Accordingly, it is thought that the use of bunker-A in a kind of test engine is possible at high load. On the other hand, it is thought that more research is needed to improve the combustion efficiency under low temperature and low load condition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.1
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• pp.33-49
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• 1997

One of the most important missons that are imposed on merchant ship at sea is to accomplish the safe transportation of cargo loaded. Recently, a study on the seakeeping performance has been carried out on the development of evaluation system related to the synthetic safety of a ship at sea. The seakeeping performance is the ship's ability sailing at, and executing its misson against adverse environmental factors successfully and safely. Until now, however, there has not been any method of quantitative evaluation on the dynamic safety of the ship's cargo loaded. In this regards, this paper has introduced the evaluation method of dynamic safety of the ship's cargo. In order to evaluate the dynamic safety of cargo, the vertical and lateral acceleration which causes the collapse, racking and local structure failure of cargo was adopted as the evaluation factors in the ship's motions. The response amplitude of ship's motions in regular waves is manipulated by NSM (New Strip Method) on a given 2,700 TEU full container vessel under the wind forces of 7, 8 and 9 Beaufort scale. Each response of ship's motions induced by NSM was applied to short-crested irregular waves for stochastic process on evaluation factors and then vertical and lateral acceleration of each cargo was compared with significant amplitude of each acceleration. A representative dangerous factor was determined by comparing permissible values of stacking and racking forces occurred typically to the vertical and transverse directions with the container strength required on ISO 1496 at the positions of forecastle, poop and ship's midship respectively. Through the occurrence probability of the determined factor by Rayleigh's probability density function, the dangerousness which limits loads on container's side wall as an evaluation was applied in judging of the danger of the ship's cargo loaded.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.241-253
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• 2020

The Small-Unit Riverine Craft (SURC) is a small high-speed vessel used by navies and marine corps in relatively shallow waterway environments, such as riverine areas or littoral coasts. In the past, SURCs have primarily been rigid-hulled inflatable boats constructed using composite materials such as glass fiber reinforced plastics. More recently, single-hull SURCs have been manufactured using aluminum for weight reduction. In this study, a Carbon Fiber Reinforced Polymer (CFRP) material was applied instead to examine its feasibility in the basic design of an SURC with a hull length of 10 m. The CFRP structural design was obtained using the properties of a marine CFRP laminate, determined in a previous study. Next, the designed CFRP SURC was modeled to confirm its functionality, then compared with existing aluminum SURCs, indicating that the CFRP SURC was 41.49 % lighter, reduced fuel consumption by 30 %, and could sail 50 NM further for every hour of engine operation. A method for reducing the high cost of carbon fiber was also proposed based on the adjustment of the carbon fiber content to provide the optimum strength where required. The data developed in this study can be used as a basis for further design of CFRP craft.

• Journal of Welding and Joining
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• v.29 no.2
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• pp.46-55
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• 2011

This paper deals with the crack propagation life assessment of T-joint welded structure where typical fatigue cracks have been frequently initiated when the marine vessels experience the storm load. Welding residual stresses are calculated to investigate its effects on the fatigue life. Thereafter the residual stress distribution was applied to the AFGROW life prediction program, which incorporated the loading, the welding residual stress, and the geometric shape of the structure. The fatigue tests of the T-joint welded specimen under storm loading show the beach mark clearly generated on the fractured section of the weldment. The crack propagation life estimated based on the beach mark is compared with that of AFGROW to validate the life prediction. Based on the results, the evaluation method of the remaining fatigue life for T-joint fillet weldment of marine vessel's cargo hold with random load or storm load was established.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.111-119
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• 2003

In order to improve navigational safety of ships, an ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface wind first and then carried out ocean wave hindercasting simulations according to the routes the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed iou pressure system Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, wave period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.

• The Journal of Fisheries Business Administration
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• v.34 no.1
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• pp.69-85
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• 2003

The primary objective of this thesis is to study, case by case, the international disputes for fishing rights between fishing nations and costal states never imagined till the introduction of the UN Convention on the Law of the Sea adopted in 1982 and came into effect in November 16, 1994, which governs the high seas and EEZ in a new manner. Such a study is to provide help in the understanding on this new marine system and how to deal with. This is addressed by the perspectives of disputes (a) in the high seas between fishing nations having traditionally enjoyed the principle of the freedom of the high seas and costal states, (b) in the EEZ between fishing nations and costal states possessing the exclusive jurisdiction over living marine resources and sovereign rights for determining allowable catch and the surplus in its EEZ. The article can be divided into four main parts. First, both the general principles of the settlement of international disputes, and the nature and procedures described in the UNCLOS are introduced. Second, it gives cases of tuna long-liner, North Pacific trawler and squid jigger occurred in the coastal states EEZ, and analyses the problem in both terms of its background and final judgment. It further describes the possible issues in case it depends on the International Tribunal for the Law of the Sea for its settlement. Third, closely tied to above, important points such as the right of hot pursuit, prompt release of vessel and crew, and the limits of cooperation with costal states inspector on board fishing vessels are considered mostly based on the UNCLOS, Bilateral Agreement and UNIA. Finally, the article concludes as follows ; The need for broad analyses on the nature of international suits and legal system for the settlement, to win the case before the International Tribunal for the Law of the Sea or coastal states court, is really acknowledged. However, considering the lack of previous studies about it, it is preferably recommended that governmental efforts for making legal standards to cover the judicial costs, for helping industry out of becoming bankrupt.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.195-208
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• 2005

The flag State is primarily responsible for implementing international maritime conventions(IMO conventions) and national laws and other standards as far as its own vessels are concerned, on the other hand the port State exercise its rights for the safety and marine environment under international law especially UNCLOS within port and territorial sea. In particular, the port State may take appropriate measures including detention of ships identified as sub-standard vessels which are considered as port State's supplementary role aiming for implementing international and national and regulations. But in the course of implementing port state control, international disputes may happen between port state, coastal state and flag state in spite of making all possible efforts to avoid these disputes. This paper aims to consider legal grounds on port state control(PSC) in international conventions and national laws concerned and deals with contradictions between international and national law arising from exercising PSC by port state control officers(PSCOs).

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.577-582
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• 2015

This paper is the fundamental study for the application of cold storage system to the transportation equipment by sea and land. This numerical study presents the solid-liquid phase change phenomenon of calcium chloride solution of 30wt %. The governing equations are 1-dimensional unsteady state heat transfer equations of $1^{st}$ order partial differential equations. This type of latent heat storage material is often usable in fishery vessel for controlling the temperature of container with constant condition. The governing equation was discretized with finite difference method and the program was composed with Mathcad program. The main parameters of this solution were the initial temperature of heat storage material, ambient temperature of cold air and the velocity of cold air. The data of boundary layer thickness becomes thin with the increasing of cold air flowing velocity and also the heat storage completion time become shorten.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.405-411
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• 2014

It needed the calculation of the required tugboat's power to move the damaged vessel to the safe area for reducing the additional damages. In this paper, it was verified the theoretical calculation method on the required power of tugboat through the 93m real ship tests. From the experiments, it was considered that the theoretical calculation method was sufficient to estimate the required power of tugboat. The resistance of the locked propeller was relatively big portions compared with other static resistances such as air resistance, frictional resistance and residual resistance. And dynamic resistance induced by swing movement and yawing was continuously occurred and it also was great effects on the total resistance. In the future, the safety factor will be considered and the exact prediction of ship's resistance will enhance the efficiency of tugboat because of the minimization of safety factor.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1319-1328
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• 2016

Since Ballast Water Management Convention has been effected, BWTS, applied to new-building vessels and existing vessels, have been developed from many countries with various treatment methods. However, BWTS is mainly typed Electrolysis, Ozone and UV type. Approximately 70 products have been type approved by the Flag Administrations. For the new-building vessels, the vessels' design and construction have been considered for arrangements and installations for BWTS. However, existing vessels which already construction had finished have problem with selection of BWTS type for installation and arrangement. The selection of the most economized BWTS system is important though, CAPEX has not been made any significant differences. However, OPEX is more important factor. Consequently, detail analysis of OPEX is the key to the selection of the most economized BWTS system and also it can be the purpose of this study. The feasibility study on the main three type of BWTS (Electrolysis, Ozone and UV type) for 175K Bulk Carrier and 57K Cargo ship has been conducted for this study. Because, these three type of BWTS have been the most frequently installed and used and the two type of object vessels are consist of the 40% of the world merchant ship market. For this study, interest rate, project duration (operation time after installation), maintenance cost and fuel oil price are considered as major factor of feasibility study. In addition, expecting Interest rates to sensitivity analysis conducted for more accurate feasibility study. For 175K Bulk carrier, ozone treatment system is more economical than other types. For 57K cargo ship, UV type is considered more economical than other types. However, it is concluded that electrolysis type is more suitable compare to installation space, total weight and electrical power consumption.