# Navigational Risk Assessment in Offshore Wind Farms Using Spatial Ship Domain Models
## 4 Discussion
The PIANC method is a simplified method commonly used to determine the minimum distance of navigating vessels from offshore installations. This method gives the same values regardless of the ship's size, speed, and planned anti-collision maneuvers. [PERSON]'s 2D domain takes into account the ship's stopping distance but does not take into account (similarly to the PIANC method) the navigational risk indicators assessed in the vertical plane, e.g., the possibility of the ship running aground or damage caused to the ship by obstacles suspended above the water (e.g., power lines, wind turbine blades, bridges). These two methods can be perceived as simplified ones, as they only depend on the spatial relationship between the ship's location and the detected navigational hazard within a two-dimensional horizontal space. This hazard may include an offshore installation, but also another vessel or land. Although these domains are easy to describe, use, and model [16] which is their indisputable advantage, they are static domains with a fixed size, which does not correspond to the case under examination. This paper proves that a more accurate ship domain should be considered for conducting safe navigation analyses within an OWF. Similar conclusions were derived, e.g., by [PERSON] et al. [36] according to whom the safe distance between wind farms and routes is related to the average speed of ships, load tons, and the length of wind farm boundaries. In this approach, [PERSON]'s 3D domain model seems to be more accurate because it takes into account UKC, OHC and, in addition, the safe distance ahead of the bow, astern, and on port and starboard sides, which is required for the ship, taking into consideration the ship's size, type, and the stop maneuver by the reversing engine from FSAH to FAS and from HAH to FAS, and the turning circle maneuver at FSAH with a rudder angle of 35\({}^{\circ}\) starboard. Moreover, the method depends on many factors, in particular: (1) the current conditions prevailing in the examined navigable area (e.g., hydrometeorological disturbances from wind, current and wave, density of navigation obstacles, presence of other ships and offshore facilities, distance to the nearest navigation hazard, depth and width of navigable areas, traffic intensity); (2) the vessel's parameters, its length, width, draft, height, maneuvering parameters, in particular, its initial speed and the distance and time needed for an emergency stop or turning circle at various engine and/or rudder settings, the type of cargo transported (safe or dangerous and its potential impact and threat to the natural environment and other ships and offshore installations). This study has certain limitations. The safe distance model presented in this paper applies only to specific water areas, and the parameters influencing the output of the safe distance model are primarily associated with local wind and currents. Additionally, the data used are derived from simulators, and it is recognized that all models are not perfect, or at least not entirely accurate. Moreover, the human factor [37] and machinery can contribute to accidents involving ships navigating in OWF waters, such as misjudgment, miscommunication between officers aboard the ship, and malfunctions of navigation equipment. These factors will be taken into consideration in future research endeavors. Although the R\({}_{\text{N}}\) indicator-based modeling provides valuable spatial risk estimates, it does not fully capture the operational challenges faced by vessels navigating near offshore wind farms. For example, turbine towers and rotating blades may cause radar shadowing and blind zones, reducing the effectiveness of ARPA systems, ECDIS updates, and visual target tracking. These effects are particularly relevant in dense OWF layouts or under poor visibility. Additionally, operating turbines generate aerodynamic wake effects that may alter near-surface wind patterns and produce wave-current interactions, which in turn can affect small vessel handling and station-keeping stability.