# Navigational Risk Assessment in Offshore Wind Farms Using Spatial Ship Domain Models
###### Abstract
A key milestone will be the commissioning of the OWFs, as this will be crucial for ensuring the security of the existing infrastructure. Simultaneously, regulating access to those areas for other sea users will become necessary. European examples illustrate varying approaches to space sharing between OWF installations and maritime traffic. In countries such as Belgium and Germany, OWF zones have been designated as exclusion areas from vessel traffic. In contrast, in Denmark and the United Kingdom, navigation through wind farms is permitted under specific conditions. In Poland, the issue of granting other users access to offshore wind farm (OWF) areas is currently the subject of intensive discussion among stakeholders. The Polish Maritime Administration is considering the introduction of so-called unconstrained passage and/or fishing within OWF zones for power-driven vessels with an overall length of up to 45 m. Currently, the Polish Maritime Administration [13], acting under Article 24 in conjunction with Article 47 of the Act of 21 March 1991 on Maritime Areas of the Republic of Poland, is contemplating the delineation of safety zones around the OWF facilities and installations located within Polish maritime areas. However, according to the Navigational Impact Analysis for the Baltic II OWF [14], navigation within OWF zones is to be permitted only at a minimum distance of 150 m from the OWF structures and installations, and only if visibility in the area at the time of passage as well as forecasted for the following 12 h, is not less than 2 nautical miles (3704 m), and the sea state does not exceed level 3 on the Douglas Sea Scale. Compliance with these conditions is to be determined based on a forecast issued by Poland's National Meteorological Service. Within the OWF safety zones, consideration is being given to permitting navigation for the following categories of vessels: (1) vessels operated by the Polish Maritime Administrtion, Polish Armed Forces, Border Guard, National Revenue Administration, and the Polish Marine Fisheries Administration; (2) vessels engaged in life- or property-saving operations or in exercises related to such activities; (3) vessels involved in marine hazard or pollution response operations or related exercises; (4) vessels compelled to enter safety zones due to adverse weather conditions or imminent danger; (5) vessels performing activities and services related to the OWF operation, including its infrastructure, or acting under legal regulations and decisions of state authorities, including maritime administration; (6) vessels conducting environmental surveys aimed at the analysis or assessment of marine resources associated with OWF operations; (7) other vessels for which written consent has been granted jointly by the director of the competent maritime office and the OWF owner or the entity responsible for the OWF operation, holding the relevant rights to the installation. The analyses presented herein constitute an important contribution to this ongoing discussion by introducing scientific perspectives. Moreover, providing a sound scientific basis for decisions regarding access to OWF areas may facilitate the establishment of a standardized approach to this issue at both the regional (Baltic Sea) and European levels. The \"ship domain\" refers to the area surrounding a vessel that is essential for maintaining safe navigation. This concept has been extensively studied in the literature on maritime safety [15], particularly in the context of collision risk assessment [16]. Assessing the risk of allisions between vessels and offshore wind farm (OWF) structures is a key factor in determining appropriate separation distances and in establishing safe buffer zones between shipping routes and OWF installations. Numerous researches have investigated various methods for calculating allision risk and have comprehensively reviewed the related literature [17; 18].