In order to assess risk as a basic step for securing safety, it requires to select risk factors and determine the frequency and the severity of the consequence of each risk factor. This research adopted common risk factors among well-known maritime risk assessment models, and proposed objective criteria to gauge the risk level of each risk factor. The starting points of risk evolution were chosen for criteria according to related studies and seafarers’ experience. The rate of risk appearance over the criteria is named as the incidence of risk factor. Therefore, the total risk level is expressed as the combination of incidence of each risk factor and severity. This quantitative method would be applied to measuring and comparing the risk level of target maritime zones, and it would also be useful to survey which risk factor be focused for reducing the total risk of a certain maritime zone.
The purpose of this study is to classify the deficient abilities of seafarers into SRK (Skill, Rule, and Knowledge) and analyze and identify the SRK by the type of accident and ship. Experimental data used the SRK cumulative frequency for 1,606 marine accident records and two-way ANOVA and t-test were used for the analysis tools. The results of two-way ANOVA showed that it is possible to identify the deficient abilities by using the cumulative frequency of SRK in both accident and ship types. As a result of the t-test, the adoption of the null hypothesis (H=0) that the mean of two pairs is equal and the rejection of the null hypothesis (H=1) were 29.2 % and 70.8 %, respectively. For the ship type, H=0 is 33.3 % and H=1 is 66.7 %. Through this study, it was found that about 70 % of the deficient abilities of seafarers inherent in maritime accidents can be identified using the proposed method.
The purpose of this study was to analyze traffic safety assessments for fishing vessels near the southwest offshore wind farm. This study applied a collision model for safety assessment. It also involved a spatiotemporal analysis of vessels engaged in fishing to identify fishing hotspots around the offshore wind farm. This study used data from fishing vessel location transmission devices gathered over 1 year in 2014. As a result, in September, when the average number of vessels engaged in fishing is high, 62 ships were operating in fishing section 184-6 and 55 ships in section 184-6. In addition, in fishing sections 184-8 and 192-2, where an offshore wind farm was located, there were 55 and 38 ships operating, respectively. As the recovery period for a seaway near wind farm turbines is 55 years, it was determined that safety measures are required in order to reduce collision frequency while allowing fishing vessels to navigate through offshore wind farms. Meanwhile, the return period of Seaway B between the groups of generators considered was 184 years. A safety zone for offshore wind farms should be installed covering a distance of at least 0.3 NM from the boundary of turbines. Then, the collision return period was derived to be close to 100 years. Through this traffic safety assessment, it has been concluded that such measures would help prevent marine accidents.
In order to develop an HNS safety management system to assess and visualize hazard levels via an automated method, we have conceptualized and configured a sample system. It is designed to quantify the risk of a vessel carrying HNS with a matrix method along navigational route and indicate hazards distribution with a contour map. The basic system which provides a visualized degree of hazards in real time has been introduced for the safe navigation of HNS ships. This is useful not only for decision making and circumstantial judgment but may also be utilized for HNS safety management with a risk base. Moreover, this system could be extended to address the navigational safety of marine traffic as well as of autonomous vessels in the near future if the sensors used are connected with IoT technology.
This paper investigates minimum safe distances relative to a ship’s four cardinal sides, as perceived by Filipino navigators when encountering dangerous elements and in adverse weather conditions when maneuvering in and around harbors. It uses a descriptive research method in the form of a questionnaire survey for experienced Filipino navigators of various ranks. During the course of research, 71 responses were colleted and the resulting data is presented in graphical and tabulated forms. Statistical methods including Pearson-product moment correlations, Cronbach’s Alpha and ANOVA were used to identify internal associations, consistencies and significances, respectively. It has been proven that there are no significant differences in minimum safe distances relative to a ship’s four cardinal sides, whether maneuvering while approaching a port or within an inner harbor. This study has been deemed significant for training future navigators, managing traffic in fairways, and designing harbors and maneuvering areas in the approaches to ports, among other applications. This work can also be used as a preliminary study for comparison with the well known safe domains presently in use.
This paper validates a system identification method using mathematical optimization using sea trial measurement data as a benchmark. A fast time simulation tool, SIMOPT, and a Rheinmetall Defence mathematical model have been adopted to conduct initial hydrodynamic coefficient estimation and simulate ship modelling. Calibration for the environmental effect of sea trial measurement and sensitivity analysis have been carried out to enable a simple and efficient optimization process. The optimization process consists of three steps, and each step controls different coefficients according to the corresponding manoeuvre. Optimization result of Step 1, an optimization for coefficient on x-axis, was similar compared to values applying an empirical regression formulae by Clarke and Norrbin, which is used for SIMOPT. Results of Steps 2 and 3, which are for linear coefficients and nonlinear coefficients, respectively, was differ from the calculation results of the method by Clarke and Norrbin. A comparison for ship trajectory of simulation results from the benchmark and optimization results indicated that the suggested stepwise optimization method enables a coefficient tuning in a mathematical way.
In this study, it was simulated and analyzed the evacuation safety to identify the cadets’ evacuation time by using maritimeEXODUS which is applied IMO MSC.1/Circ.1238 theory as well as the trim and heel which are the major factor of reducing the ship evacuation speed. In addition, this study carried out a simulation through the special program for fire analysis - FDS (Fire Dynamics Simulator) in order to find the effective evacuation time, i.e. life survival time. Particularly, this study did comparative analysis of the influence on the survival of cadets based on the collected simulation data by fire size and sort. As a result of the analysis, It was analyzed the Evacuation Allowable Limit Temperature 60°C and resulted that there is no influence in evacuation by temperature. As a result of the analysis on visibility evacuation limit 5 m, it was found that the only one evacuation rallying point could not meet the evacuation safety. However, it derived the perfect evacuation safety under the condition of two rallying points available on wood fire. In case of Kerosene, it was satisfied the evacuation safety if the heeling was under 10°. Moreover, it could not meet the evacuation safety by evacuating through upper deck although there were two evacuation rallying points. When it was set by the lifeboat descending maximum angle-20°heel and 10°trim which was described in SOLAS regulation, it was simulated that the wood fire having two evacuation rallying points in the center of the ship satisfied the evacuation safety.
This paper is to study a technique to detect the real-time route aberrance on the passage route using bumper area of the ship domain theory. In order to evaluate the risk of route aberrance, a quarter line was created between the center line and the outer line, and a passage route with the image line outside the outer line was designed. It calculated the real-time route aberrance with the vessel bumper area to measure the risk level on the passage route. The route aberrance using overlap bumper area was simulated through three kinds of scenario vessel at the designed passage route. In this paper, we proposed Ratio to Aberrance Risk as one of the evaluation parameter to detect the route aberrance risk at each sector in the passage route and to give the evaluation criteria of 5 levels for seafarer’s navigation safety. The purpose of this work is to provide the information of the route aberrance to seafarer automatically, to make it possible to prevent the human errors of seafarer on the high risk aberrance route. As the real-time risk of route aberrance on the passage route is automatically evaluated, it was well thought that seafarer can have only a little workload in order to know the risk of route aberrance at early-time. Following the further development of this work, the techniques for detecting the real-time route aberrance will be able to use the unmanned vessel.
This study suggests design criteria to evaluate the availability of anchorage in Korea to contribute to ship safety by presenting necessary design criteria for anchorage volume according to port development. Accordingly, the concept of “necessary volume of anchorage” is introduced to evaluate the volume of anchorage available in Korea’s major ports, and classify these ports into three types according to the characteristics of incoming ship. Numerical simulations designed using MATLAB-SIMULINK have been carried out to track the irregularly of arrival and, waiting times along with the environmental conditions that affect anchorage and necessary volume of anchorage have been suggested based on these tests. Finally, in order to complete a function equation analysis, the necessary volume of anchorage with reference to cargo volume is addressed using regression analysis as follows. Group A - YNA=0.0002XHA−3.67 , Group B - YNB=0.0002XHB−6.82 , Group C - YNC=0.0001XHC+9.02 . This study contributes to a review of anchorage volume from the perspective of harbor development.
The purpose of this study is to keep the safety of the car ferry passengers and vessels by investigating and analyzing vessel safety management systems in Korea and China. To this end, we investigated Korea-China car ferries and the current status and causes of global marine accidents corresponding to the sizes of the vessels from Korea and China. Furthermore, we investigated car ferries’ crew management and safety management. As a result of the analysis of the ferry accident, the causes of human error and ship’s age were the greatest, but the ship’s companies showed a negative stance regarding the age restriction. It seems that it is necessary to utilize the near-miss accident reporting system and differentiate the management of ship’s aging. Also, it was analyzed that both the ship company and the crew of the ship need to strengthen their awareness of safety management.
In this study, a survey was conducted among students who received ARPA/radar simulation training in order to verify the effect of training. An effective training method based on the analysis results was also proposed. Furthermore, this study analyzed full mission simulation conducted over one semester, and found that training effect increased as time passed. The survey showed improvement in skills related to radar/ARPA utilization, ARPA decoding, ship handling, and overall skill. Students responded practical skills improved more than theoretical knowledge, and also analysis showed that ship handling skills had a larger effect than radar decoding skills on improving overall skill, therefore proposed that theoretical education regarding the functions of radar and ARPA should be reinforced in ARPA/radar simulation training.
CE RCD (Recreational Craft Directive) is a certification for the design and construction of small vessels, including pleasure yachts, which are widely used not only in the countries within the European Union, but also in Japan and Southeast Asia. Recently, South Korean leisure craft shipyards have developed interest in exporting to foreign leisure craft markets such as Europe; however, they have encountered difficulties because of the CE RCD regulations, which are relatively complex and difficult to understand. The requirements for buoyancy and stability, which are essential properties that must be understood within the early stage of ship design, are defined based on ISO 12217. However, preparing this assessment according to ship classification regulations is an exceedingly complex task, even with knowledge of naval architecture. In this research, we have developed design support tools to systematically support assessments and preemptively define design information so that buoyancy and stability assessments based on ISO 12217 can be systematically prepared. Our research results were applied to actual examples of yacht design to confirm validity. We believe that the improved yacht design process presented in this research can act as a foundational reference for enhancing the effectiveness and systematic buoyancy and stability assessments.
Cylindrical shells are often used in ship structures at deck plating with a camber, side shell plating at fore and aft parts, and bilge structure part. It has been believed that such curved shells can be modelled fundamentally by a part of a cylinder under axial compression. From the estimations with the usage of cylinder models, it is known that, in general, curvature increases the buckling strength of a curved shell subjected to axial compression, and that curvature is also expected to increase the ultimate strength. We conduct series of elasto-plastic large deflection analyses in order to clarify the fundamentals in buckling and plastic collapse behaviour of cylindrical shells under axial compression. From the numerical results, we derive design formula for predicting the ultimate strength of cylindrical shell, based on a series of the nonlinear finite element calculations for all edges, simply supporting plating, varying the slenderness ratio, curvature and aspect ratio, as well as the following design formulae for predicting the ultimate strength of cylindrical shell. From a number of analysis results, fitting curve can be developed to use parameter of slenderness ratio with implementation of the method of least squares. The accuracy of design formulae for evaluating ultimate strength has been confirmed by comparing the calculated results with the FE-analysis results and it has a good agreement to predict their ultimate strength.
In this research, we have calculated characteristics of wave-piercing high-speed planing hull, by using a RANS solver and overset grid method, for comparing with experimental measurements of that and simulating with several appendages, since the computed results of commercial CFD code look reasonable for the prediction of the performances of planing hulls on calm water in planing conditions. As a result, it is confirmed that the dynamic instability phenomena in pitch and heave motions (porpoising) occurred after a certain FnV, and effectively suppressed using some of appendages, especially the 0.5L spray rail is suppressed to 24-55 % in the pitch motion and 33-55 % in the heave motion. In spray phenomenon, 1L hard chine suppress spray effectively and it is effective to set the angle of appendages to be less than 0° in order to suppress wave.