25 

 20 



15 



r 



-1 





1949 

 Total Observations 



- 9R?9 





r 



1 





1950 

 Total Observations = 



! 



= 2741 





^ 







21 Observations > 30.3 ft 



^ = 7.36 ft 

 (7,2 = 20.52 ft2 









17 Observations >30.3 ft 



A= 7.50 ft 

 f^s^ = 26.01 ft2 









~i 











_. 













•1 











r- 







- 



>-, 













_ 













^. 



n_ 



















l-TT 





1— 1— >_, 

















1951 



Total Observations = 2797 

 29 Observations > 30.3 ft 



^ = 8.45 ft 

 a/ = 34.81 ft2 











1952 

 Total Observations = 2820 

 6 Observations > 30.3 ft 



^=7.40 ft 

 a/ = 20.52ft2 



r 



1 















r- 



1 















-| 





r- 









■p 













[- 









-\ 











- 











- 



H^ 



1-1 r- 

















ih=Li^ 



T— 1 1_ 





15 20 25 30 35 



10 15 20 25 30 35 



Significont Wave Height, ft 



Figure la - Frequency Distributions of Yearly Samples 



distributions determined from observations made by weather ships at ocean station "Charlie" 

 (52° N, 37° W) in the North Atlantic from 1 January 1949 to 31 May 1953. The observations 

 were made every three hours by trained weather observers in accordance with instructions 

 prescribed by the United States Weather Bureau. ^ The observations are reported as the 

 average of the significant* wave heights. Only one quantitative measurement was recorded 

 each time the sea was observed. 



Hydrographic Office Data 



Figure 2 shows combined frequency distributions of wave heights for periods of 2, 7, 

 and 40 years tabulated by the U.S. Hydrographic Office^ at the request of the Model Basin. 

 These observations, also at station "Charlie," were made by German merchant ships from 

 1901 to 1939. The data are not as reliable as the data presented in Figure 1; because routes 



♦Generally defined as the mean value of the one-third highest waves; see definitions page vi. 



