UNCLASSIFIED 



SECURITY CLASSIFICATION OF THIS PAGEfWTmi Call Entered) 



and evaluated the existing technical literature (theoretical, field, and 

 laboratory) on floating breakwater concepts. 



While floating breakwaters provide a lesser assurable degree of protection 

 than a permanently fixed breakwater, they are in general less expensive and 

 can be moved from one location to another. The cost of a floating system is 

 only slightly dependent on water depth and foundation conditions. Adequate 

 wave reduction or energy attenuation can be attained by a floating breakwater 

 only if the incident wave is of a relatively low height. A reasonable magni- 

 tude appears to be an incident wave height not exceeding 4 feet, with a 

 corresponding wave period not exceeding 4 seconds. Floating breakwaters can 

 attenuate waves with these incident characteristics to a magnitude tolerable 

 in a small-craft mooring area (wave heights up to 1.5 feet). Open-ocean 

 applications of a distinctly different concept can be formulated to withstand 

 substantial increases in the incident wave characteristics. 



A group of prismatic structures contains the simplest forms of floating 

 breakwaters. This group offers the best possibilities for multiple use as 

 walkways, storage, boat moorings, and fishing piers. In addition to mass, the 

 radius of gyration and the depth of submergence appear to significantly influ- 

 ence the attenuation characteristics. As the ratio of breakwater width-to- 

 wavelength increases to values greater than 0.5, the wave attenuation features 

 of the structure not only improve markedly, but the net result of the forces 

 on the mooring and anchoring system becomes substantially less. This occurs 

 because the wave dynamics are exerting forces on a part of the structure in a 

 direction opposite to those forces on other parts of the breakwater. 



UNCLASSIFIED 



SECURITY CLASSIFICATION OF THIS PAGEOVhen Date Entered) 



