or seaplane can operate only in waves up to 1 meter, operation in the 

 North ^3ea during a stormy winter will be limited to 50 per cent of the 

 time. 



Values for wave dimensions at different states of the sea are 

 considerably scattered. Mean values based upon observation and measure- 

 ment from lightship FEHHIARNBELT in the Baltic Sea are: 



State of the Sea Wave Height Meters 



2 0.30 



3 0,50 



4 Oo80 



5 1.25 



Observations from three lightships in the North Sea at a state of the 

 sea 3 indicate a mean wave height of about 1 mater. The ratios between 

 wave heights and wave lengths vary considerably. Shallow waves with 

 H/L = 1:20 were more frequently encountered than steep waves, both in 

 the Baltic and North Seas, 



REFERENCES 



(1) Arbeitsgruppe fur Seegangsforschung, Lilienthal-Qesellschaf t. 

 1937, "Uber Seegangsbestimraungen," (Determination of the State 

 of the Sea), Report A 37 /l Hamburg, 



(2) Mewes, E, 1937, "Kricht uber die Tatigkeit der Arbeitsgruppe fur 

 Seegangsforchung 1936-37," (Activity report of the Hydrographic 

 Section - Prdlirainary report to report 082/00/+ of Lilienthal- 

 Gesellschaft), 



(3) Thorade, Herman, 1931. "Probleme der Wasserwellen," (Water 

 Wave Problems), Hamburg, 



(4.) U, S. Navy Hydrographic Office, 1944. "Wind Waves and Swell 

 Principles in Forecasting," H, 0. Misc. Publ, 11,275. 

 (Translator's reference). 



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