• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.5
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• pp.487-495
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• 2016

In the offshore project such as semi-submersible FPU and FPSO, the free fall type life boat called TEMPSC (Totally Enclosed Motor Propelled Survival Craft) has been installed for the use of an emergency evacuation of POB (People on Board) from the topside platform. For the design of life boat arrangement for semi-submersible FPU in the initial design stage, the drop height and launch angle are required fulfill with the limitation of classification society rule and Company requirement, including type of approval as applicable when intact and damage condition of the platform. In this paper, we have been performed the numerical studies to find proper arrangement for the life boats consider drop height in various environmental conditions such as wave, wind and current. In the calculations, the contributions from static and low frequency (LF) motions are considered from the hydrodynamic and mooring analysis as well as damage angle from the intact and damage stability analysis. Also, Air-gap calculation at the life boat positions has been carried out to check the effect on the life boat arrangement. The air-gap assessment is based on the extreme air-gap method includes the effect of 1st order wave frequency (WF) motions, 2nd order low frequency roll/pitch motion, static trim/heel and set down.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.849-855
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• 2011

Emergency batteries on board are used for stairs, pathway lights, and emergency communications during alternator black-out. In addition, there are engine start-up batteries in lifeboats. Typically, these batteries are installed under the Classification Rules. However, Since batteries inside life boats are installed in a confined narrow space, it is difficult to perform regular maintenances. Also, even though there are air vents in the life boat, the temperature inside the life boat often reaches above $65^{\circ}C$, which is much higher than the regulation temperature, $45^{\circ}C$. In this paper, we will summarize the accident of battery explosion occurred in MMU training ship, and possible causes. We will propose preventive measures of battery explosions as well as the revision of the regulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2559-2565
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• 2013

Material of boat hull has been used mainly with FRP composite materials until now. FRP boat hull manufacturing began to be restricted after the 2000's under international regulation on ocean environment safety. Shipyard on a small scale has manufactured polyethylene canoe and kayak hulls. Polyethylene has the melting point lower than the existing hull materials. Thermal stress occurs on outer hull surface when the polyethylene boat hull is exposed to sunlight. If it happens everyday, boat hull undergoes fatigue damage due to thermal fatigue. Therefore, this study presents the statistical fatigue life estimation on the HDPE boat hull subject to repeated thermal stress under three point bending condition.

• Journal of Navigation and Port Research
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• v.41 no.2
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• pp.63-70
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• 2017

Despite the remarkable continual growth of the world cruise industry, studies have yet to be attempted on many revenue management problems in cruise operations. This paper suggests two schemes that can be easily applied to cruise revenue management: optimal dual pricing and passenger safety level. In optimal dual pricing, a pair of higher and lower prices is applied to cabin reservation through market segmentation. This scheme can be executed with a linear price-response function for the current unreserved cabins. A cruise line could benefit from this scheme to maximize reservation revenue while attaining full occupancy. The dual pricing scheme is also devised to produce only integer demands to suit real management practices. The life boat capacity is an additional service capacity unique to the cruise industry, catering to passengers' safety. The concept of passenger safety level is defined and computed for any passenger life boat capacity of a cruise ship. It can be used to evaluate the passenger safety of a cruise ship in operation, as well as to determine the number of life boat seats required for a new cruise ship. Hypothetical examples are used to illustrate the operation of these two schemes.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.78-83
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• 2008

In recent years, small boats used for marine leisure have been steadily increasing because of the increase in national income and the desire for marine leisure. But the repair of such small boats in dry dock has pointed out many faults in small FRP-shipbuilding in terms if workspace and manpower. Lifting a boat from the water to land is done with a crane or by hand using a sling around the bottom of the boat. But dry dock work is limited by the scale of the boat, which corresponds to the crane capacity, with carelessness making it possible to capsize a boat and endanger life. The purpose of this study was the development of a marine docking system that would improve economical efficiency and safety, for which we carried out concept design, model tests, structural analysis, etc.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.19-21
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• 2007

우리나라 조선산업은 생산성 향상을 통한 건조척수의 증가를 통하여 일본과 더불어 세계 $1^{\sim}2$위의 시장 점유율을 기록하는 등 세계 최고의 수준이다. 그러나 국내 중소형 조선소나 조선기자재업체의 경우에는 기술 인력의 부족으로 인하여 독자적인 기술의 확보와 기술개발 여건이 마련되어 있지 않은 상황이다. 특히, 구명정(Life boat)은 선박의 비상 탈출 장비로써 법적으로 의무 설치가 강제화 되어 있는 선박 안전에 있어 필수적인 장비로서 수요도 꾸준히 증가하고 있으나, 국내의 구명정 제작업체로는 현대라이프보트가 유일하며 2004년 기준 국내 신조선박에 탑재되는 수량의 25%, 세계시장의 4% 만을 공급하고 있다. 이외의 수량은 $7^{\sim}8$ 개의 유럽 등 외국업체와 중국업체들이 제작, 공급하는 실정이다. 이에, 본 연구에서는 구명정의 신선형 개발과 선형시험 통한 성능 검증 및 품질 향상과 풍수절감을 위한 생산성 향상 방안, 기존 몰드 개선 방안 연구 등을 수행하고 시제선을 건조하여 저가의 외국 구명정에 대응하여 국내 구명정 기술 경쟁력을 향상시킬 수 있는 전폐형 구명정의 국산화를 달성하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.47-54
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• 2014

Endurance of ship hull can be estimated by existing regulations and fatigue estimation methods. These can be applied to the hull materials that are recommended by ship regulations but can't be applied to new materials. In this study, structural force in the worst sailing condition is obtained by the acceleration measurement test of small polyethylene boat and the endurance of small polyethylene hull is estimated by rainflow cycle counting method and linear cumulative damage rule. Maximum Von-Mises stress on the polyethylene boat is 1.8MPa and much lower than the fatigue strength of at least 5.9MPa for the fatigue life of $1{\times}10^9$ cycles. Fatigue life of the polyethylene boat hull is estimated to be 6,229 years.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.99-104
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• 2015

Life rafts, which has been used for domestic vessel currently, are fabricated mostly for the ocean-going vessels in accordance with the SOLAS Resolution. Therefore, there is not any small-sized life raft which can be installed on small fishery boat, leisure boat and cargo vessel with those length shorter than 20 meters in our country. However, in many foreign countries, new standards or the small-sized life rafts applicable to those small vessel have been developed according to the standard of ISO 9650. Furthermore, they make their effort to contribute the safety for the life at sea by supply the superior product of life rafts, which have been adopted by light material (i.e. thermoplastic polyurethane, TPU) and economic production process (i.e. heat sealing, radio-frequency welding, RFW), etc. In this paper, the development results of the small-sized life raft, which has been used the lightening material TPU and fabricated by RF-welding method, will be introduced.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.1-8
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• 2002

When a body enters waters, its original kinetic energy or momentum is distributed among the body and surrounding water in the form of added mass. Due to the transfer of the energy or momentum, the bode is subjected to the hydrodynamic impact forces and acceleration. This impact behavior can be an important criterion of submersible vehicle launched to the air. In this paper, based on Life-boat model, an approximate method is proposed for the evaluation of the forces and responses of cylindrical rigid bode by water entry impact. The impact forces are calculated by yon Karman's momentum theory and motion responses the body, especially acceleration, are calculated by a numerical integration of the motion equations derived by hydrodynamic force equilibrium. The proposed method is expected to be a simple but efficient tool lot the preliminary design or motion analysis of a body subjected to water entry impact.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.79-83
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• 2018

According to the Korea Robotics Industry Association, the number of robots companies, sales and production are steadily increasing until 2016, and the global robot market outlook is expected to continue to increase until 2025. We need to develop more attention to robots that can make life easier for us and can replace human tasks that we cannot do. It is predicted that robots will be more developed in the future with the above statistics, and future robots will be more activated by robots that can depend on each other, fix each other, and adapt to the changing environment without humans. Therefore, the shape of the robots in the future will be developed as a group robot(swarmbot) that cooperate with each other while the robot works. These robots have been studied for a longtime, but there are only two community robots that are applied in real life, only two of which are jailbreaking robots made in KAIST and KIVA robots made in Amazon company. In the future, as these robots develop more and more, and environment where robots can live without human intervention is created, so that a plurality of robots can collaborate and do individual work.