# Navigational Risk Assessment in Offshore Wind Farms Using Spatial Ship Domain Models
## 2 Materials and Methods
### Hydrometeorological Data  
Environmental scenarios, including moderate and deteriorated hydrometeorological conditions, were based on regional Baltic Sea data and reflect typical navigation challenges. Extreme weather such as ice-covered waters was excluded from this study but is recognized as a significant future consideration. The values of average and deteriorated conditions used for our analysis come from the publication entitled \"Admiralty Sailing Directions: Baltic Pilot Vol. 2 (Np19), 18 th Edition 2022\" (26) and \"Sailing Directions of the Baltic Sea--Polish Coast\" (27) (Table 3). The spatial domain model parameters for the chosen vessel types were estimated based on the data presented in Table 2. This study specifically examines navigation under average and deteriorated hydrometeorological conditions relevant to the selected location.  
\begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{4}{c}{**Type of Ship and Its Parameters**} \\ \hline  & **VLCC (Very Large** & **Fishing Boat (Fisher)** & **Z-Drive Prevention** \\  & **Crude Carrier)** & & **Response Tug** \\ \hline DWT [t] & 159,584 DWT & 1676 DWT & 300 DWT \\ Engine power [kW] & 15,500 kW & 840 kW & 2 \(\times\) 3800 kW \\ Length overall (L = LOA), from & L = LOA = 261.3 m & L = LOA = 65.6 m & L = LOA = 45.0 m \\ stern to bridge (L\({}_{\text{RF}}\)) and from & L\({}_{\text{AR}}\) = 51.8 m & L\({}_{\text{AR}}\) = 25.3 m & L\({}_{\text{AR}}\) = 30.5 m \\ bridge to bow (L\({}_{\text{RF}}\)) [m] & L\({}_{\text{RF}}\) = 209.5 m & L\({}_{\text{RF}}\) = 40.3 m & L\({}_{\text{RF}}\) = 14.5 m \\ Width B [m] & 48.3 m & 10.3 m & 12.5 m \\ Draft T = T\({}_{\text{max}}\) [m] & 15.0 m & 5.4 m & 4.9 m \\ Overall height H\({}_{\text{L}}\) [m] & 77.3 m & 32.3 m & 21.0 m \\ Air draft H\({}_{\text{N}}\) = A\(\times\) T [m] & 62.3 m & 27.0 m & 16.1 m \\ Hull Block coefficient C\({}_{\text{B}}\) & 0.85 & 0.64 m & 0.614 \\ Full Ahead (FSAH) = 15.0 km & Full Ahead (FSAH) = 12.6 km & Full Ahead (FSAH) = 15.0 km \\  & \(\approx\) 7.7 m/s & \(\approx\) 6.5 m/s & \(\approx\) 7.7 m/s \\ Ships Speed [kn] & Half Ahead (HAH) = 10.1 km & Half Ahead (HAH) = 8.9 km & Half Ahead (HAH) = 5.7 km \\  & \(\approx\) 52 m/s & \(\approx\) 4.6 m/s & \(\approx\) 2.9 m/s \\  & & Deep Water: Advance = 86 m \\ Parameters for ship turning & Advance = \(AD_{\text{max}}\) = 926 m \(\approx\) 3.5-L & Advance = 213 m \(\approx\) 3.2-L & \(\approx\) 1.9-L \\ (circulation) and emergency & Transfer = \(TR_{\text{max}}\) = 889 m \(\approx\) 3.4-L & Transfer = 241 m \(\approx\) 3.7-L & Shallow Water: Advance = 89 m \\ \(AD_{\text{max}}\), \(TR_{\text{max}}\) [m] & & \(\approx\) 1.9-L & Transfer = 108 m \(\approx\) 2.4-L \\  & & & \\ Stopping Distance & FSAH-FAS = 3704 m \(\approx\) 14.2-L & FSAH-FAS = 667 m \(\approx\) 10.2-L & FSAH-FAS = 77 m \(\approx\) 1.9-L \\ \(AD_{\text{max}}\) [m] & HAH-FAS = 1482 m \(\approx\) 5.7-L & HAH-FAS = 333 m \(\approx\) 5.1-L & HAH-FAS = 22 m \(\approx\) 0.5-L \\ \hline \end{tabular}
\end{table}
Table 2: The representative vessel types and their parameters. Data derived from the Wheel House Posters.  
This study does not explicitly account for potential local hydrometeorological changes caused by the presence of offshore wind turbine (OWT) structures, such as altered wind flow, current deflection, or localized wave disturbance. Although such effects may occur depending on the wind farm's layout and density, as well as turbine dimensions and prevailing sea state, they are generally of limited spatial extent and were considered negligible in the context of the deterministic R\({}_{\text{N}}\) model applied in this study. These secondary influences are therefore beyond the scope of the current analysis but are recognized as a potential limitation. Future research may incorporate high-resolution environmental modeling to investigate the impact of OWF-induced flow alterations on ship maneuverability and navigational risk levels.