P* = 1.35 arises after a duration t = 22.1 hours (example for v = 

 16 m/sec in Table 8, 3), and Table 10). With this, the sea has al- 

 most attained its final stage, and this stage is not signified only 

 by this p*-wave, but also by the presence of the other two dominat- 

 ing waves, that is, by their interference pattern. Strictly speak- 

 ing, the final state is attained when p^^* = 1.37 has developed, but 

 in this state A - D = and this happens theoretically for x (or t) 

 -» 00 . For practical purposes p* = 1.35 will approximate the fully 

 arisen state, because the variations from §♦ = 1.35 to p ♦ = 1.37 may 

 be neglected.. For the growth of the long waves with increasing 

 fetch and duration see figxires 15-19 and figure 26. 



In the fully arisen state of (wind-driven) complex sea three 

 characteristic waves dominate the surface pattern. The smaller waves 

 which are superimposed contribute only to a certain roughness of 

 this main pattern. But this roughness is very important for energy 

 transfer by wind, and therefore for maintaining the main pattern of 

 the sea. 



In our example, v = I6 m/sec, the fully arisen complex sea is 

 characterized by the following dominating waves: 



B„-wave 

 '^m 



p(l)-wave 



Pr„*-'wave 

 ^m 



X-^ = 107 m H^ = 5.9 m (T^ = 8.3 sec) 



A3 = 163 m H3 = 6.6 m (Tg = 10.2 sec) 

 X2 = 307 m Hg = 6.8 m (T^ = 14.0 sec) 

 Some theoretical interference patterns of complex wave motion 

 for fully developed sea at v = I6 m/sec are represented in Figures 

 7 and 8 in Chapter I. They show theoretical "wave records" and the 

 variations in space and time as they could be forecasted for a fixed 

 point on the sea surface. The computed variations of time intervals 



117 



