Page 167 - Theory and Design of Air Cushion Craft

150 Stability

0.2

OQ

0.1

15 17 19 21 23
p cll c (kgflm ) 3

Fig. 4.15 Relative transverse righting arm g variation with cushion length beam ratio PJL r
l

h
0.20
717

0.15

0.10

0.05

0.05 0.06 0.07 0.08 Z bs/B c

Fig. 4.16 Influence of bow/stern seal relative gap Z bs/# c on relative initial static transverse metacentric height.

Effect of the cushion length beam ratio on the transverse stability
The calculated transverse stability of craft type 717 with different cushion length/
beam ratios is shown in Fig. 4.17.
From Table 4.4, it is found that the initial transverse stability at large heeling angles
will not change significantly, for several variations of SES type 717, as long as the
cushion pressure is kept constant, even though with different cushion length/beam
ratio, weight and cushion pressure/length ratio for different types of craft. It is not