# Impact Force Mechanism of a Trimaran Model and Its Experimental Validation
## 5 Water-Slamming Experiment and Force Analysis
### Summary and Analysis of Experimental Results  
Experimental data, including the slamming-pressure coefficients and measuring points, are summarized in Table 7.  
As seen in Table 7, compared to the data obtained from the model without flexible cladding, the slamming-pressure coefficient obtained from the group covered with a 2 mm thickness is very small; however, the measured slamming-pressure coefficients are several times larger than those obtained from the group covered with a 1 mm thickness. This may be because the thickness of 1 mm is very small, resulting in the silicone sheet \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Working** & & & & & & & & \\
**Condition** & & & & & & & & & \\ \hline
**Pressure/Pa** & **Speed** & **Slamming-Pressure Coefficient** & **Pressure/Pa** & **Speed** & **Slamming-Pressure Coefficient** & **Pressure/Pa** & **Speed** & **Slamming-Pressure Coefficient** \\ \hline P01 & 34,893.9 & 2.242 & 13.88 & 45,097.6 & 2.183 & 18.93 & 36,727.5 & 1.965 & 19.02 \\ \hline P02 & 24,180.1 & 2.362 & 8.67 & 21,502.5 & 2.183 & 9.02 & 24,345.6 & 2.073 & 11.33 \\ \hline P05 & 8601.0 & 2.037 & 4.15 & 16,472.8 & 1.927 & 8.87 & 10,080.4 & 1.965 & 5.22 \\ \hline P06 & 27,845.2 & 2.117 & 12.43 & 19,826.0 & 2.061 & 9.33 & 24,044.9 & 1.965 & 12.45 \\ \hline P08 & 46,355.4 & 2.419 & 15.84 & 41,194.1 & 2.273 & 15.95 & 31,151.7 & 2.073 & 14.50 \\ \hline P10 & 35,696.1 & 2.314 & 13.33 & 28,860.4 & 2.183 & 12.11 & 10,955.9 & 2.073 & 5.10 \\ \hline  & & **H14** & & & & & & **H16** & \\ \hline P01 & 28,300.8 & 1.753 & 18.42 & 27,736.3 & 1.716 & 18.84 & 25,999.6 & 1.515 & 22.66 \\ \hline P02 & 25,237.7 & 1.855 & 14.67 & 21,832.9 & 1.716 & 14.83 & 20,406.8 & 1.557 & 16.84 \\ \hline P05 & 5114.6 & 1.692 & 3.57 & 5209.9 & 1.570 & 4.23 & 5880.3 & 1.432 & 5.74 \\ \hline P06 & 19,260.1 & 1.692 & 13.46 & 11,229.2 & 1.621 & 8.55 & 13,374.1 & 1.515 & 11.65 \\ \hline P08 & 24,869.8 & 1.753 & 16.19 & 21,926.3 & 1.757 & 14.21 & 18,934.6 & 1.432 & 18.47 \\ \hline P10 & 20,193.8 & 1.753 & 13.14 & 23,321.6 & 1.716 & 15.84 & 17,098.5 & 1.579 & 13.72 \\ \hline \end{tabular}
\end{table} 
Table 6: Experiment with 1 mm silica gel sheet, opening at the positions of pressure sensors. Figure 19: Slamming-pressure coefficient for a 1 mm thick flexible cladding, opening at positions of pressure sensors. being pasted on the wooden stick (shown in Figure 1) too tightly so that there was an air cushion between the pressure sensor and the water. In such a case, although the thickness is small, the reduction in slamming pressure is quite obvious. This shows that if there is space (an air cushion) between the surface flexible cladding and the trimaran model, the reduction in slamming pressure is obvious. By comparing the 2 mm and 4 mm thickness, we find that as the thickness increases, the slamming-pressure coefficient becomes smaller and smaller until it approaches a constant when the thickness is big enough. In order to reduce the influence of the air cushion, processing method 5 was designed. The experimental data, including the slamming-pressure coefficients and measuring points, are summarized in Table 8.