Figure 100. Wave-Maze scrap-tire floating breakwater concept protecting the 

 east marina and northern section of Pier 39, San Francisco, 

 California. 



VI. A-FRAME ARRANGEMENT FLOATING BREAKWATERS 



Because of the availability of timber in both the United States and 

 Canada, individual logs or log rafts have been used to provide protection for 

 harbors and boat anchorages. The deeply indented coastlines of British 

 Columbia and Alaska have many harbors (large and small) which are well pro- 

 tected by natural topography from the action of storm-generated waves. How- 

 ever, numerous coastal settlements and potential harbors exist which are 

 exposed to some degree to waves, and which would benefit greatly from the 

 installation of an effective and economical type of breakwater. WES has 

 investigated the applicability of specific arrangements of floating log break- 

 waters for Alaskan areas, and the Canadian Department of Public Works has 

 developed and evaluated a floating circular-cylinder design concept which also 

 incorporates a vertical wall for supplemental attenuation purposes. Of inter- 

 est in this development has been the determination of the method and extent to 

 which the requirement of large mass may be usefully replaced by large moment 

 of inertia of mass. It appears that the Canadian concept (the A-frame) effec- 

 tiveness range can be significantly increased by a large increase of its 

 radius of gyration, involving only a slight increase of mass. 



149 



