# Navigational Risk Assessment in Offshore Wind Farms Using Spatial Ship Domain Models
## 2 Materials and Methods
### Types of Representative Ships  
For our analyses, we selected three vessels: a Very Large Crude Carrier (VLCC), a fishing boat, and a Z-Drive Prevention Response Tug (Z-Tug). The three vessel types selected represent a spectrum of maritime operations in OWF areas, from small maneuverable service units to large transiting tankers. This selection enables the assessment of model sensitivity across vessel sizes and maneuvering capabilities.  
The parameters of selected vessel types used in our analysis are presented in Table 2. Numerical models and operational (maneuvering) data were derived from various sources, including the specific details of the vessels, Wheel House Posters with the vessels' maneuvering parameters, the author's own sea experience when maneuvering on this type of vessel. Additionally, data from the maneuvering simulator provided by the Faculty of  
\begin{table}
\begin{tabular}{c c} \hline
**Abbreviation** & **Full Term** \\ \hline R\({}_{\rm NLA}\) & Horizontal component of the navigational risk indicator (\(R_{N}\)) that concerns keeping an adequate required safe distance from the nearest danger astern of the ship \\ R\({}_{\rm NWP}\) & Horizontal component of the navigational risk indicator (\(R_{N}\)) that concerns keeping an adequate required safe distance from the nearest danger on the ship’s port side \\ R\({}_{\rm NWS}\) & Horizontal component of the navigational risk indicator (\(R_{N}\)) that concerns keeping an adequate required safe distance from the nearest danger on the ship’s starboard side \\ SD\({}_{\rm D}\) & Ship Domain Depth calculated below the waterline \\ SD\({}_{\rm H}\) & Ship Domain Height calculated above the waterline \\ SD\({}_{\rm LF}\) & Ship Domain Length Forward calculated horizontally ahead from the center of the ship’s layout \\ SD\({}_{\rm LA}\) & Ship Domain Length calculated horizontally astern in the aft direction from the center of the ship’s layout \\ SD\({}_{\rm LA}\) & ship’s layout \\ SD\({}_{\rm WP}\) & Ship Domain Width (beam) calculated to the Port side from the ship’s heading line \\ SD\({}_{\rm WS}\) & Ship Domain Width (beam) calculated to the Starboard side from the ship’s heading line \\ TSS & Traffic Separation Scheme \\ UKC & Under-Keel Clearance \\ VLCC & Very Large Crude Carrier \\ Z-Tug & Z-Drive Prevention Response Tug \\ \hline \end{tabular}
\end{table}
Table 1: Cont.  
Navigation at Gdynia Maritime University was utilized. This included the NaviTrainer 5000 Professional (Wartsila Voyage Oy, Helsinki, Finland) (with ship models according to the Wartsila Navi-Trainer Professional 6, Technical Description and Installation Manual Version 6.0, issued in December 2022) in conjunction with the ECDIS NaviSailor 4000 electronic chart system from Transas, which is part of the Wartsila Group. Simulation data were generated using the NaviTrainer 5000 Professional system (Wartsila Voyage Oy, Helsinki, Finland) and ECDIS NaviSailor 4000. Key parameters extracted include initial and final speeds, stopping distances, turning radii, time to stop, and drift under no-thrust conditions. These values were input into the 3D domain model to define spatial safety margins for each vessel type. The simulator outputs were validated against standard maneuvering test data and literature values to ensure realism. It is noted that the R\({}_{\text{N}}\) indicators calculated in this study are deterministic and scenario-specific; stochastic variability and probabilistic modeling approaches were not applied but are considered a direction for future research.