Wove crests 



Figure 2-40. Diffraction for a single breakwater normal incidence. 



FIND ; The wave height at a point P having coordinates in units of wave- 

 length X = 3 and y = 4. (Polar coordinates of x and y are r = 5 at 

 53°.) 



SOLUTION: 



Since d = 5 meters, T = 8 seconds. 



L 1.56T^ (1.56)(64) 

 o 



= 0.0501 



Using Table C-1 with 



the corresponding value of 



therefore, 



L = 



- = ^= 0.0501 

 o o 



_ or 1^ = 0.0942 



= 53.06 m (174 ft) 



0.0942 



Because 1 centimeter represents 16 meters on the hydrographic chart and L = 

 53.06 meters, the wavelength is 0.0332 meter or 3.32 centimeters (1.31 

 inches) on the chart. This provides the necessary information for scaling 

 Figure 2-36 to the hydrographic chart being used. Thus 3.32 centimeters 

 represents a radius-wavelength unit. 



2-91 



