• Journal of Positioning, Navigation, and Timing
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• v.7 no.4
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• pp.217-226
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• 2018

According to the Korea Coast Guard's maritime disaster statistics (Korea Coast Guard 2017, Korean Statistical information Service 2018), an average of 2,140 marine accidents occurred every year for the past 6 years and the number of accidents is increasing every year. Among them, maritime accidents of fishing vessels are the most frequent, and recently accidents involving fishing boat and leisure vessels are rapidly increasing as well. In particular, the number of accidents involving leisure vessels increased to about one-third of the accidents of fishing vessels, and emergency rescue requests are increasing every year accordingly. However, the number of crash accidents involving users of small vessels and marine leisure activities are increasing because of the difficulties of installing navigation equipment and electronic navigation charts. Recently, the demand for precise positioning using mobile devices is increasing in the fields of maritime safety, piloting support, and coastal survey. Although various applications of smart devices provide location-based services for users, the measurement results are discontinuous when using the position coordinates of the National Marine Electronics Association (NMEA) calculated by smartphone. Recently, Google announced that they will provide GPS raw data to developers from Android 7.0 Nougat. As a result, developers have an opportunity to receive precise carrier phase and code measurements to make more accurate positioning according to the performance of Android devices. This study analyzed GPS positioning performance using Android devices, and compared and analyzed the positioning performance at sea with high-performance GPS receivers.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.226-232
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• 2024

During scuba diving in Korea, accidents involving bodies being struck by the ship propeller when entering and exiting the water, repeatedly occur every year. In response to the need to reduce accidents and implement safety management measures, Korea has established regulations for the installation and management of propeller guards. However, owing to the absence of clear production regulations in domestic laws and regulations, the installation standards are ambiguous, and the inspection items are limited to the appearance and fixation status. As a result, the safety of divers in propeller accidents is not guaranteed. Therefore, this study was conducted to specify the current legal requirements for the installation and inspection of propeller guards. To achieve this goal, we conducted a thorough analysis of the current state of domestic and foreign propeller guards and the legal factors pertaining to safety standards. Based on this analysis, we identified specific areas for improvement and proposed a plan to enhance the system for installation and inspection. The installation standards for propeller guards were clearly outlined in terms of the lattice size and material. Additionally, inspection standards were proposed for appearance, fixation, and material condition, along with clear indicators for assessing them.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.1
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• pp.93-99
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• 2013

It is expected to continue to increase the number of people who enjoy marine and water sports due to the increase of leisure time because of income increase, the five-day workweek, etc. However, in the safety awareness, the development of equipment is just in the early stage. Established system for fundraising is required for Korean marine and water sports to be developed first. Should the fund be spent on the safety and development of domestic equipment for marine and water sports, it would make for a safer and more enjoyable sports for the people. The profit return measures of motor boat race, among marine and water sports, are surveyed and analyzed to suggest the measures stated above. Japanese legal structure and the profit return measures on motor boat race, which are about 60 years ahead than Korean systems, were analyzed and led to suggest the establishment of professional institutions which promote motor boat, etc. and the legal improvement for funding.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.8
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• pp.911-916
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• 2014

The leisure boat industry has the potential to become a high-value-added industry in the future. Recently, a study on Korean high-speed leisure boats for fishing was conducted. This study suggests a product configuration model-based shipbuilding cost estimation method for determining the type of leisure boat suitable for mass production, as part of a research for productivity improvement. The suggested estimation method based on the analysis of the leisure boat process and generic YWBS can calculate quantitative and concrete data. By using this method, the cost of building the catamaran-type design ship can be reduced by 17 times, compared to that of the monohull-type mother ship. This implies that the final design of the Korean high-speed leisure boat for fishing will have a competitive price at the actual production stage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.482-488
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• 2019

Leisure and business facilities have been steadily developing in Korea. Among waterborne leisure vessels and equipment, the distribution and sale of kayaks and canoes have significantly increased. Previously, (FRP) materials were primarily employed for constructing kayaks. However, owing to global warming and depletion of natural resources, the demand for non-polluting renewable energy is rapidly increasing, which has increased the demand for carbon fibers. To meet the requirements of changing social consciousness, a carbon fiber-based commercial kayak was designed in this study. Resistance analysis and structural safety were conducted by employing software tool for verifying the reliability of the proposed kayak. The pressure resistance and frictional resistance were examined in a wide range of speed. Obtained results indicate that at speeds greater than 2.6 m/s, the pressure resistance significantly increases and the total resistance also increases. Furthermore, the results corroborate that the proposed kayak structure has a adequate safety with respect to the design loads that are considered during operating conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.147-153
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• 2015

The International Maritime Organization has conducted SEEMP for reducing $CO_2$ emission from ships. The study was carried out by comparing the real application of three shipping companies with IMO guideline about SEEMP on the same category. This paper suggests a method to improve implementation of SEEMP more efficiently through a grasp of the problem from its real application. Improvements are error correction of Company EEOI, unification of EEOI data acquisition period, compliance of measurements for fuel-efficient operation, suggestion of $CO_2$ mass conversion factors for various fuel and EEOI goal setting through formal standards of the International Maritime Organization.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.365-372
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• 2024

The South Korean marine industry is emerging as a significant market, driven by the growing popularity of various water leisure activities, including sailing. This trend suggests a rising demand for sailing yachts. Consequently, since 2022, the design and development of a 28ft sailing yacht have been ongoing, supported by the government and the Ministry of Oceans and Fisheries, to promote yachting culture in South Korea. The Velocity Prediction Program (VPP) analysis was conducted using WinDesign during the preliminary design stage to evaluate performance and determine design parameters. The hydrodynamic model used for this vessel is based on regression methods developed from years of experience in naval architecture and yacht research at the Wolfson Unit, providing reliable estimates for most modern yachts. However, owing to the lack of specific hydrodynamic data from towing tank tests or CFD numerical analysis, verification of the hydrodynamic model has faced some challenges. Additionally, an incomplete weight estimate resulted in variable VCG values, potentially affecting stability and overall performance. The optimal boat speed for this vessel was determined at true wind speeds (TWS) of 4, 8, 12, 16, and 20 knots, using both the jib (up to 120° TWA) and the spinnaker (from 80° TWA). The optimized speed of the yacht was found to be comparable to that of international similar-class yachts.

• Journal of Ocean Engineering and Technology
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• v.31 no.6
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• pp.419-424
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• 2017

Unlike other leisure boats, a sailing yacht is propelled by wind power using sails that are controlled by the crew. Therefore, the ergonomic design of the equipment that the crew has to operate for sailing might be very important. However, it is difficult to find design rules and regulations for the equipment arrangement of a sailing yacht based on ergonomics. In this study, the arrangement design for the height and side plate angle of a winch for a sailing yacht was examined from an ergonomic design point of view. In a simulation, a Korean male in his 20s was selected as a human model for a grinder. The physical load was analyzed when he was operating a winch using a 3D human simulation. The lower back load showed the highest value when using the grinder at $90^{\circ}$ and $180^{\circ}$. Based on the results for the lower back load when using the grinder with various winch heights, it is suggested that the winch height from the cockpit floor to the top of the winch should be more than 40% of the height of the human operator. In addition, according to the results for the lower back load with various horizontal distances from the body, it is suggested that the side plate angle should be less than $16^{\circ}$.

• Corrosion Science and Technology
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• v.9 no.1
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• pp.48-55
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• 2010

The many vessels are built with FRP(Fiber-Reinforced Plastic) material for small boats and medium vessels. However, FRP is impossible to be used for recyclable material owing to environmental problems and causes large proportion of collision accidents because radar reflection wave is so weak that large vessels could not detect FRP ships during the sailing. Hence, Al alloy comes into the spotlight to solve these kinds of problems as a new-material for next generation instead of FRP. Al alloy ships are getting widely introduced for fish and leisure boats to save fuel consumption due to lightweight. In this study, it was selected 6061-T6 Al alloy which are mainly used for Al-ships and carried out various electrochemical experiment such as potential, anodic/cathodic polarization, Tafel analysis, potentiostatic experiment and surface morphologies observation after potentiostatic experiment for 1200 sec by using the SEM equipment to evaluate optimum corrosion protection potential in sea water. It is concluded that the optimum corrosion protection potential range is -1.4 V ~ -0.7 V(Ag/AgCl) for 6061-T6 Al alloy, in the case of application of ICCP(Impressed current cathodic protection), which was shown the lowest current density at the electrochemical experiment and good specimen surface morphologies after potentiostatic experiment for Al-Mg-Si(6061-T6) Al alloy in seawater environment.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.5
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• pp.294-302
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• 2021

In this study, the 3D printing technique called design for additive manufacturing (DfAM) that is widely used in various industries was applied to marine leisure ships of equipment. The DfAM for the stanchion for crew safety was applied to the equipment used in an actual recreational craft. As design constraints, the design alternatives were not to exceed the safety and weight of the existing stainless steel material, which were reviewed, and the production of a low-cost FFF-type 3D printing method that can be used even in small shipyards was considered. Until now, additive manufacturing has been used for manufacturing only prototypes owing to its limitations of high manufacturing cost and low strength; however, in this study, it was applied to the mass production process to replace existing products. Thus, a design was developed with low manufacturing cost, adequate performance maintenance, and increased design freedom, and the optimal design was derived via structural analysis comparisons for each design alternative. In addition, a life-cycle assessment based on the ISO 1404X was conducted to develop sustainable products. Through this study, the effectiveness of additive manufacturing was examined for future applications in the shipbuilding industry.