In this paper, two indexes for own ship risk collision assessment in the restricted water are proposed. The first one concerns the collision threats for ships. The second one describes threats that are generated by human error. It is carried out dynamically with accordance to changes in time. To realize the main aim of the paper, the definition of the extended domain of the ship is introduced. Furthermore, the rules to determine the indexes and range of their values are developed. Finally, a comprehensive model and its potential application are presented. There are some important things to take into account during the model development: the interface, the levels and type of the output information, the type and accuracy of the information about the position and movement dynamics of the particular ships. It gives the opportunity to consider the different operation levels. In addition, it also allows us to take into account the different levels of measurement and the collision risk warnings. This approach can be helpful for both the VTS operator and OOW, the ship’s navigator, as the tool to support the safe navigation in restricted water.
This paper presents an overview of ship traffic volume and accidents in the Baltic Sea with a special focus on the Gulf of Finland. The most common accidents are groundings and collisions, usually reported to be caused by human error. The annual number of Baltic Sea accidents reported to HELCOM varied from 34–54 for collisions and 30–60 for groundings. The number of yearly port calls varied from 468–505 thousand with a peak in 2008. Exact port call data could not be found for all ports and hence had to be estimated. The number of line crossingings in HELCOM AIS data was found to be a good, rough surrogate measure for the total number of port calls and could be used if more precise port call data was not available. By analyzing two separate accident databases, an estimate for accident underreporting was calculated. Different statistical methods yielded an underreporting rate in the range of 40–50%. Lastly, the true number of accidents was estimated, based on the estimated underreporting percentage for the Baltic Sea. Based on these results, the true number of true accidents should be first estimated if accident statistics are used in building or validating maritime risk models. When using such models or accidents statistics in decision-making, the underlying uncertainty in the accident statistics should be taken into account as the underreporting frequency estimates are only approximations of the real number of accidents.
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A great number of papers dedicated to ships collision on. The basic difficulty is a complex probable nature of this phenomenon on the one hand and considerable influence of the human factor (difficult to be formalized by mathematical methods) on the other. This paper suggests one of such models, simplified to a great extent. It doesn't, for example, describe dangerous situations when ships are going in one direction overtaking each other. Its practical importance is the matter to be discussed. But in any case the authors think that its getting more precise and complicated will give an impetus to a new approach to the problem. It will make possible to avoid subjectiveness and mistakes in the future at forecasting catastrophes.
PL
W ostatnim czasie pojawia się wiele artykułów poświęconych kolizjom statków. W niniejszym referacie prezentowany jest model matematyczny opisujący kolizję statków. Zasadniczą trudnością jest, z jednej strony, złożony charakter tego zjawiska, a z drugiej strony, znaczny wpływ czynnika ludzkiego, który trudno opisać metodami matematycznymi. W referacie proponowany jest pierwszy taki model. Jest on w dużym stopniu uproszczony i nie opisuje, na przykład, niebezpiecznych sytuacji, gdy statki wyprzedzają się płynąc w jednym kierunku. Omówiona została kwestia praktycznej użyteczności opisanego modelu. Zdaniem autorów, rozszerzenie zakresu i zwiększenie dokładności modelu zainicjuje nowe podejście do zagadnienia. W przyszłości będzie możliwe uniknięcie subiektywizmu i błędów przy przewidywaniu katastrof.
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