Analysis of dynamic navigation risk factors in internal waters by using multi criteria decision making approach

Maritime transport is the main mode of transportation for international and local commerce due to its high capacity to transport freight and its environmental friendliness compared to other modes of transportation. Increasing capacity and traffic intensity in maritime transport has made maritime safety an increasingly important issue. In this context, new solutions and measures were needed to ensure / improve safety at sea. In order to avoid disasters, loss of lives and goods damages resulted from marine accidents, international organizations, governments and institutions regulated and implemented practices to prevent accidents. It has been assessed that risk assessments can be performed to decrease the number of marine accidents that can not be avoided by the regulations and practices implemented and thus to ensure safety at sea. The hazards that the ship may encounter depend on many risk factors that affect the overall risk level of the ship. Risk variables/factors collected in four groups; Static risk factors, Risk factors related to the route of navigation, Dynamic risk factors, Risk factors related to the history of the ship. In the relevant study, Dynamic risk factors were discussed. Dynamic risk factors include factors that change during navigation. These are; ship speed, DCPA, TCPA, weather, current, wind, traffic intensity, visibility, distance to danger, sea condition, etc. Risk assessment, a key element of safety at sea, is an important issue in maritime studies and projects. The use of dynamic risk assessment of sailing ships and therefore decision-making mechanisms have become a necessity when it is assumed that marine accidents with severe consequences are experienced during navigation and that the risk of navigation is dependent on many variables. From this need, in academic studies, real-time / dynamic risk calculations and decision support mechanisms have been developed with different approaches. Given the studies and decision support mechanisms related to dynamic risk assessment of sailing ships, it has been determined that navigation risk factors vary across different studies and that their effectiveness were not assessed. Identification of the factors affecting the dynamic risk assessment of navigating vessels by evaluating the navigation risk factors and the determination of the importance values of these factors were seen as a motivation source for this thesis. With this motivation, firstly the literature and algorithms used for risk analysis in maritime domain were investigated and information about the factors affecting the dynamic risk calculation for navigation used in the literature for collision/ grounding events were collected. In the course of the study, research on maritime risk assessment was conducted, information was given on this issue, types of risk factors were explained and decision support systems were mentioned. It has been considered that factors affecting dynamic risk calculations of navigation in internal waters are more effective and that a large proportion of marine accidents take place in internal waters, a study on internal waters would be an example to other waters and encompass the factors of other marine waters. Literature research and expert opinions have determined the dynamic factors affecting the risk of navigation for the collision and grounding event, and the hierarchical structure of these factors, which were determined in the presence of the experts, was also established. At this stage, the reviews of pilot masters and experienced oceangoing masters have been consulted due to their knowledge and experience in the field of work. The number of main dynamic risk factors of navigation determined in the study for collision are nine; which are defined as Traffic Density, Target Tendency Observation, Ship Maneuverability, Stability Factors, Technical Characteristics, Ship Dimension, Vessel Speed, Visibility and Environmental Factors. Twenty-one sub factors were located under these main factors. The main factors of the dynamic risk factors specified in the study for grounding are also nine; which includes Traffic Density, Distance to Hazard, Ship Maneuverability, Stability Factors, Technical Characteristics, Measurable Ship Features, Ship Speed, Visibility and Environmental Factors. Nineteen sub factors were specified under these main factors as well. Analytic Hierarchy Process method (AHP) which is developed to solve the weighting problems by Thomas Lorie Saaty was used as a multi-criteria decision making method in the study. This method, which is one of the most frequently used multi-criteria decision making methods in the literature is applied to a wide range of fields such as health sector, archaeology, finance, tourism, administration, education and engineering etc. In the method, the decision maker makes simple quantitative comparisons that will be used to determine priority values for purposes such as selection and evaluation. In the study, eleven experts were surveyed and the weights of the factors affecting the dynamic risk of navigation were separately analyzed and interpreted by the Analytic Hierarchy Process (AHP) method for collision and grounding occurrences. The factors affecting the collision and grounding discussed in the analysis are examined and their results were compared to each other. As a result of examining the factors, the results that can contribute to the literature have been obtained. Some factors that are not used extensively in the literature have been found to play an important role in the dynamic risk assessment of navigation for collision and grounding. When the weights of collision factors and grounding factors were compared, some values were found close to each other while some factors were different. It is aimed that the information obtained through the literature search made within the scope of the related research will be a source reference for new researchers, and a guiding reference for selection/determination of criteria affecting dynamic risk assessment of navigation. It is also aimed that the weighting factors affecting dynamic risk of navigation for collision and grounding will provide support for the quantitative evaluation of the criteria for the decision makers and help to obtain more productive results in risk models by taking into account the differences in the importance values of the used factors and so it will contribute to provide safety in the maritime sector.