25 

 20 



15 

 10 



1949 

 Sampling Period = 1 year 

 Total Observations = 2832 

 21 Observations > 30.3 ft 



1949 - 1951 

 Sampling Period = 3 years 

 Total Observations = 8370 

 67 Observations > 30.3 ft 



.Y = 7.82 ft 

 o} = 21.29 ft2 



1949 - 1950 

 Sampling Period = 2 years 

 Total Observations = 5573 

 38 Observations > 30.3 ft 



^ = 7.51 ft 

 a2= 23.11 ft2 



1949-1953 I 



Sampling Period = 4!'2 years 

 "Total Observations = 12,365" 

 73 Observations > 30.3 ft 



A= 7.76 ft 

 c^ = 25.87 ft2 



10 



20 25 



30 35 5 10 



Significont Wave Height, ft 



20 25 



30 35 



Figure lb - Combined Frequency Distributions 



Figure 1 - Frequency Distributions of Samples of Significant Wave Heights Observed at 

 Ocean Station "Charlie" by U.S. Weather Observers 



X is the mean and, a is the variance. The observations greater than 30.3 ft were included in the totals given 

 but are not shown on the histograms. 



were often avoided at times of high seas. Fewer extreme values were recorded. 



MEASURED WAVE DATA 



Figure 3a is the frequency-distribution pattern of measured wave heights produced by 

 the wavemaker at the Taylor Model Basin. These were simulated to represent a characteristic 

 confused sea. Only 43 measurements were made. 



Figure 3b shows a frequency distribution of wave heights measured at sea by means of 

 a pressure recorder. These data were tabulated on a form that shows the relation between 

 wave heights, lengths, and periods."* Since measurements were made for a period of only 30 

 minutes, it may be assumed that they represent the characteristics of the sea at that time and 



