# Determination of the Waterway Parameters as a Component of Safety Management System
## 1 Introduction  
The aim of the work described in the paper was to build an application of the integrated navigation safety management system (INSMS) for coastal waters and harbour approaches in order to easily estimate the risk level of a selected part of the waterway in predefined hydrometeorological and navigation conditions. Such analyses require complex calculations, simulations, and expert knowledge [1]. They are usually carried out during a fairway's definition and deployment phases but rarely while operating ships in the fairway on a daily basis [2]. The premise of the developed computer application was that it should support the daily work and decision processes of the persons responsible for the vessel traffic management in the approach and harbour waters. On the other hand, such a system could likewise be a very useful tool for designing new waterways and modifying existing ones. Due to different manoeuvring limits in various types of water areas, the INSMS for restricted water areas (approaches to ports) requires a systematic approach to the safety assessment [3]. Such an approach covers the use of models of navigational risk assessments appropriate and adequate to the specific navigation conditions. The developed INSMS application codenamed \"NEPTUN\" includes the following modules representing the various aspects analysed in terms of the safety level assessment (Figure 1):  
1. [label=(0)]
2. marine accident statistics module;
3. questionnaire survey module;
4. waterway calculation module for a given part of fairway;
5. risk analysis module;
6. recommendation module for the route being implemented based on the incident analysis;
7. legal regulation analysis module.  
All of the above modules use data stored in the database of the SQL server. Such a solution is dictated by their large number and the fact that some of the computations, due to their complexity and time consumption, are performed in the data server as well. The results of these calculations are, in turn, sent to the client application installed on the end user's computer. The application is dedicated mainly to port authorities as a tool assisting in the navigation safety assessment of a fixed segment of a waterway. As well as related proposals of navigation decision systems assisting in anticollision manoeuvres in open waters [4], \"NEPTUN\" can be applied during the post-factum analysis.  
The INSMS \"NEPTUN\" is used for assessment of the navigation or manoeuvring risk as an advisory system for traffic control services, but it is also possible to use its individual modules to carry out specific research. The module for determining the width of the safe manoeuvring area was used in this study, presented in Sections 3-5. This investigation concerned the possibility of allowing a bulk carrier of parameters exceeding the ones set in the harbour regulations to enter the port of Szczecin in Poland. As the result of this study, a set of waterway parameters was obtained as the basis for the consecutive process leading to changes of the aids in navigation or even reconstruction of some parts of the fairway.