be transferred from the wind over the shorter waves to longer waves 

 with <r> V, as long as in the energy balance A - D>0. 



When in the generating process of complex wave motion the 

 first characteristic waves (B -waves) attain their maximiim steep- 

 ness, the wave length of these waves, or their propagation velocity 

 respectively, is given by 6 (equation (60))and their height H by 

 (17) • In this stage of wave development, a certain amount of energy 

 in the difference A - D is left, and this remainder is used for 

 generation of longer waves until an equilibrium state is attained 

 between the acting forces, that is, between the drag, the normal 

 pressure forces and the dissipative forces. Without additional in- 

 crease of the effective resistance of the sea surface, and therefore 

 without an additional increase of the total drag at a given wind vel- 

 ocity, this stage A = D will be approached by nature in the easiest 

 way when waves which proceed with a phase velocity equal to the wind 

 velocity (<r = vj p(l) = 1) are generated. 



Let us assume that the sea surface takes on a waviness which 

 corresponds to the wave length of p(l)-waves, originally beginning 

 with very small disturbances which may always be present. By tak- 

 ing up energy from wind, the height H(l) of these disturbances will 

 increase until it attains its maximum value. This maximum height, 

 H(l) , is given by the maximum steepness, according to (17) 



6(1)^ = 2n e"^ = 0.0406 . (63) 



Thus 



H(l)jjj = A(l) 2n e'^ . (63a) 



The total wind forces at the sea surface have not changed dur- 

 ing the generation of these "intermediate waves" or p(l)-waves. As 



90 



