statistical Data on the North Atlantic Coast - This is also a 

 portion of the General Investigations program. Four stations along the 

 Atlantic Coast (Penobscot Bay^, Mid-Cape Cod^ Hudson River and Chesapeake 

 Bay entrance) were chosen for analysis^ and three years of data obtained 

 from the weather charts for each station. This data is presently under 

 analysis , 



Wave Tanlt Study of VJave Energy Loss By Bottom Friction and 

 Percolation - Model tests on wave energy loss by friction and pei'colation 

 show that losses by these means may be quite significant where long gentle 

 slopes occur (the Gulf Coast for example). Comparison with theoretical 

 results derived by Putnam and Johnson at the University of California 

 sho^J good qualitative agreement, and fair quantitative agreement if the 

 friction parameter and permeability of the sand are correctly evaluated, 

 A report on the test results is being prepared and should be published about 

 Januar-y 1953. 



Study of Parallel Lines Method for Detecting and Measuring Wave 

 Trains - This method was described in the July 1952 Bulletin^ and further 

 work is in progress to determine the applicability of the method for 

 practical use. V^aves in crossed i\rave patterns (confused sea) in 

 aerial photographs have been separated by this method and xjave lengths 

 measured. Depths computed from these wave lengths were in fair agreement 

 vrith soundings, and it is thought the method may be of considerable aid 

 in the accurate determination of depths from aerial photos. 



Use of Rayleigh Disc as Wave Direction and Force Indicator - 

 Work has been resumed on the possible use of the Rayleigh Disc with a 

 damped support rather than having the disc completely free swinging. 



Effect of Cylindrical Obstacles on Waves Passing Around Them - 

 The probable necessity of supporting a rail carried movable truss for 

 an instrument support in the Coastal Model Basin has caused initiation 

 of an examination of the effect of pipe supports on waves passing around 

 and beyond the supports. Pipes of varying size are being placed in the 

 small wave tank and the wave characteristics of the waves behind the pipe, 

 •vri. th and without the pipe in place, are being measured and coraparedo 



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