## 4 Re-Designing of the Appropriate Fairway Width
### Results of Grounding Probabilities  
Based on the maritime traffic flow and traffic volume analyzed in Section 3, the frequency of grounding of IWRAP Mk II was derived by applying the maritime traffic environment according to the scenario shown in Figure 7. By reflecting the characteristics of each fairway, obstacles and low-depth sections in the vicinity were also reflected. Figure 10 highlights the results of the estimated frequency of grounding for each fairway.  
The closest island, reef, and low-water zone were set as the grounding standard. In the case of the Yeosu fairway, because there is a marina and a low-depth section on the right side of the fairway, the fairway was set as the grounding standard on the right side, and the grounding standard was set on the left side of the fairway, according to the water depth for each draft. Table 9 shows the grounding probabilities based on the estimated grounding frequency and traffic volume.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Wando**} & \multicolumn{3}{c}{**Yeosu**} & \multicolumn{3}{c}{**Masan**} & \multicolumn{3}{c}{**Gadeok**} \\ \cline{2-13}
**ES Value** & \(ES_{A}\) & \(ES_{L}\) & \(ES_{S}\) & \(ES_{A}\) & \(ES_{L}\) & \(ES_{S}\) & \(ES_{A}\) & \(ES_{L}\) & \(ES_{S}\) & \(ES_{A}\) & \(ES_{L}\) & \(ES_{S}\) \\ \hline
0–500 & 14.1 & 16.1 & 97.4 & 49.9 & 69.5 & 86.2 & 13.6 & 15.4 & 94.1 & 26.0 & 64.9 & 57.8 \\
500–750 & 79.8 & 83.7 & 1.1 & 33.6 & 28.9 & 5.8 & 72.6 & 80.0 & 1.8 & 30.9 & 34.4 & 12.5 \\
750–900 & 4.4 & 0.2 & 0.2 & 7.6 & 1.6 & 1.4 & 9.2 & 4.5 & 0.6 & 12.2 & 0.6 & 4.1 \\
900-1000 & 1.7 & 0.0 & 1.3 & 8.9 & 0.0 & 6.6 & 4.7 & 0.0 & 3.5 & 30.9 & 0.0 & 25.6 \\ \hline \hline \end{tabular}
\end{table}
Table 8: ES value for each destination fairway.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Name of Fairway** & \begin{tabular}{c} **Traffic Volume** \\ **(Actual/7 Days)** \\ \end{tabular} & \begin{tabular}{c} **Traffic Volume** \\ **(Estimated/Year)** \\ \end{tabular} & \
\begin{tabular}{c} **Predicting Grounding** \\ **Frequencies** \\ \end{tabular} &
\begin{tabular}{c} **Grounding** \\ **Probability** \\ \end{tabular} \\ \hline Wando & 779 & 40,619 & 0.0294852 & 7.2590 \(\times\) 10\({}^{-7}\) \\ Yeosu & 1274 & 66,430 & 0.146378 & 2.2035 \(\times\) 10\({}^{-6}\) \\ Masan & 957 & 49,901 & 0.302582 & 6.0636 \(\times\) 10\({}^{-6}\) \\ Gadeok & 1002 & 52,247 & 0.107486 & 2.0573 \(\times\) 10\({}^{-6}\) \\ \hline \hline \end{tabular}
\end{table}
Table 9: Probability of grounding by fairway.  
Following the evaluation criteria established in Section 4.1, we judged that there exists a risk of grounding when the probability of grounding exceeds \(10^{-4}\) when the frequency of grounding for the total vessel traffic is prepared. Based on the 7-day traffic data, when the estimated frequency of grounding for each fairway was calculated from the estimated ship traffic for one year, the Wando fairway showed a grounding probability of \(7.2590\times 10^{-7}\), the Yeosu fairway had a grounding probability of \(2.2035\times 10^{-6}\), the Masan fairway had a grounding probability of \(6.0636\times 10^{-6}\), and the Gadeok fairway had a grounding probability of \(2.0573\times 10^{-6}\). The grounding probability was found to be lower than \(10^{-4}\) for all fairways subject to evaluation; thus, the risk of grounding was found to be good in the current traffic and sea area conditions.