13 



CONCLUSIONS 



1. Frequency distributions of wave heights are not normal but tend to peak toward the 

 lower wave heights. They do, however, have a pattern which is approximated by a logarith- 

 mically normal distribution. 



2. The frequency distribution of pitch angle for the USCGC CASCO has the same general 

 form as that shown to be applicable for the wave heights. It is reasonable to expect that this 

 pattern will also hold for other ships. 



3. The frequency distribution patterns of the pitch angles measured on the USCGC 

 CASCO show a correlation with those of the wave height observations. 



4. The Pearson Type I Curve may be fitted to frequency distributions of wave heights. 



ACKNOWLEDGMENTS 



The studies made in conjunction with this report were done under the supervision and 

 guidance of Mr. N.H. Jasper. Members of Statistical Engineering Laboratory of the National 

 Bureau of Standards, namely Mr. I. Richard Savage, Mt. Marvin Zelen, and Dr. Edgar King 

 made suggestions as to treatment and presentation of data. The wave height data presented 

 in various figures was obtained with the cooperation of members of the Division of Oceano- 

 graphy, U.S. Hydrographic Office and Aerology Branch, CNO. Finally, the author is indebted 

 to Dr. George Suzuki for review of the statistical mathematics in this report and the suggestion 

 of Appendix 2. 



REFERENCES 



1. TMB Itr S29/12 (732:AWM:cae) to CNO (Aerology Branch) of 30 July 1953. 



2. "A Manual of Marine Meterological Observations," U.S. Weather Bureau Circular M, 

 8th Ed (1950). 



3. U.S. Hydrographic Office Itr Code 541-LBB/rvg of 10 July 1953. 



4. Ehring, H., "Kennzeichnung des Gemessenen Seegangs auf Grund der Haufigkeitsver- 

 teilung von Wellenhoehe, Wellenlaenge und Steilheit," T. B. 4 (1940), pp 152-155 (Translation: 

 U.S. Hydrographic Office, SIO Wave Project, Report 54, Contract Nobs 2490). 



5. Jasper, N.H., "Study of the Strain and Motions of the USCGC CASCO at Sea," TMB 

 Report 781 (May 1953). 



6. Harney, L.A. et al, "A Statistical Study of Wave Conditions at Four Open-Sea Locali- 

 ties in the North Pacific Ocean," NACA Technical Note 1493 (Jan 1949). 



7. "Waves in the North Pacific Ocean," U.S. Hydrographic Office Jan-Dec, H.O. Misc 

 11, 117-1. 



