# Navigation Safety on Shipping Routes during Construction  
[PERSON]  
1 Marine Engineering Department, Klaipeda University, H. Manto Str. 84, LT-92294 Klaipeda, Lithuania; [EMAIL_ADDRESS] (V.P. ); [EMAIL_ADDRESS] (D.P.) [PERSON]  
1 Marine Engineering Department, Klaipeda University, H. Manto Str. 84, LT-92294 Klaipeda, Lithuania; [EMAIL_ADDRESS] (V.P. ); [EMAIL_ADDRESS] (D.P.) [PERSON]  
1 Marine Engineering Department, Klaipeda University, H. Manto Str. 84, LT-92294 Klaipeda, Lithuania; [EMAIL_ADDRESS] (V.P. ); [EMAIL_ADDRESS] (D.P.) Footnote 14: [[https://www.mdpi.com/j](https://www.mdpi.com/j)]([https://www.mdpi.com/j](https://www.mdpi.com/j))conditions, changes in weather conditions, and the need for additional assistance from tugs or vessel traffic control (VTC) services. Importantly, the mentioned decisions must be made before the ship's master receives permission to enter the port, navigational channel, or other restricted area. Nevertheless, sometimes, information from VTC or other dedicated systems comes too late. This is why the advanced calculation of the minimum parameters of the passages for vessels becomes significant in facilitating the decision-making process [2]. In order to make rational decisions, the possession of knowledge regarding the methods for calculating the passages for ships on the route may be helpful. However, sometimes, the calculation results and evaluations made in advance cannot be applied in practice due to the following possible changes [3]:  
* The ship's internal conditions (e.g., maneuverability changes depending on the sailing area);
* The ship's external conditions (e.g., weather conditions changing in a short period of time, shallow water in some areas);
* The traffic of other ships in the analyzed area and hydrodynamic interactions between ships on short distances. During the construction, renovation, or other improvements in navigational channels or adjacent areas, a decrease in the navigational passage's width and depth may take place. Moreover, it should be noted that the location of the construction work may change with its progress; work within navigational channels is usually performed on separate sections, which are improved over a certain period [4]. An analysis of the literature revealed that the available methodologies or recommendations for the calculation of navigational channel parameters [5] are not always used in practice due to the number of approximations or a need to possess a significant amount of additional data [6,7]. Practically applicable calculation and evaluation methodologies should comprise external and internal forces and moments influencing the ships, taking into account the ship's maneuverability and other parameters. Methods for assessing a ship's optimal trajectory in narrow passages have been developed [8,9]; however, many of them do not include the complex assessment of the ship's movement and are not practically useful in real operating conditions. This article aims to develop a methodology that allows for the precise determination of the limited conditions for the navigation of ships passing through areas in navigational channels where construction or development works are being carried out. The scientific novelty of the research deals with the development of a methodology for calculating a ship's trajectory and sailing band in narrow passages considering hydro-metrological and hydrological conditions to improve navigation safety. This article includes a Section 2, where selected navigational channels are characterized, and the available related research studies are analyzed. In Section 3, the methodology for calculating the ship's trajectory and sailing band in navigational channels in restricted sailing conditions is presented. The developed methodology considers the internal and external forces that act on the ship in narrow passages during construction work in navigational channels. The Section 4 includes a case study description and calculation results that prove the possibility of applying the presented methodology in practice.