insensitive to variations in this parameter. The same central values and 

 roughly the same scatter occur for low- steepness (mostly swell) and high- 

 steepness (active wind sea) conditions. 



200. There are several important conclusions from this analysis. One 

 is that there never appears to be a wave field which is unidirectional. 

 Another is that directional spread (as defined here) appears to exist in the 

 range 20 to 60 deg with a most common value near 40 deg. This distribution 

 appears roughly to be independent of the three bulk parameters (height, 

 period, and direction) conventionally used to characterize sea state. This 

 suggests that the distribution of directional spreads shown in Figure 16 is a 

 reasonable characterization for most sea states which occur at this and 

 similar sites. 



82 



