FLOATING BREAKWATER FIELD ASSESSMENT PROGRAM, 

 FRIDAY HARBOR, WASHINGTON 



bij 



B.H. Adee, E.P. Riahey , 



and D.R. Chris tens en 



I. INTRODUCTION 



Floating structures for use in the attenuation of water waves were 

 introduced by Joly (1905) . Little was done with the concept until the 

 Bombardon floating breakwater was deployed to form a harbor during the 

 Normandy invasion of World War II. The use of mobile harbors for po- 

 tential military applications provided the incentive for extensive work 

 during the postwar years. Representative articles from this period 

 include those by Minikin (1948) who discussed floating breakwaters in 

 general terms, Carr (1951) who used basic mechanics to predict trans- 

 mission characteristics, and the review of the performance of the Bom- 

 Bardon by Lochner, Faber, and Penny (1948). In 1957, the Naval Civil En- 

 gineering Laboratory, Port Hueneme, California, began a concerted ex- 

 ploration of the existing knowledge of transportable units that could 

 serve as breakwaters or piers. Results of the study are summarized in 

 Naval Civil Engineering Laboratory (1961) , which was an invaluable 

 state-of-the-art assessment with particular emphasis on military uses 

 under the rather severe site criteria of an incident wave with a 15-foot 

 height, 13-second period, minimum water depth of 40 feet, inshore trans- 

 mitted wave height of 4 feet, and tidal range of 12 feet. A sequel to 

 the earlier study (Naval Civil Engineering Laboratory, 1971) surveyed 

 concepts for "transportable" breakwaters, including over 60 in the 

 "floating" category. Although no breakwater system was disclosed which 

 would meet the stringent military site criteria and transportability 

 requirement, these state-of-the-art reviews sparked renewed interest in 

 the floating breakwater for nonmilitary applications. A review of de- 

 velopments in floating breakwaters was summarized by Richey and Nece 

 (1974); Seymour (1974) introduced a new and innovative concept for wave 

 attenuation using a system of tethered floats which may have application 

 over a wide range of wave conditions. 



Continually increasing pleasure boat ownership has nearly exhausted 

 the available supply of moorage space in many areas. The need for addi- 

 tional moorage space in conjunction with escalating construction costs 

 and more stringent environmental restrictions require careful scrutiny 

 of alternatives to the traditional fixed breakwater and excavation tech- 

 niques employed in marina construction. Productive time in weather- 

 dependent, waterbome activities such as construction, logging, and cargo 

 handling could be increased if protective floating, transportable break- 

 waters were used. Other uses in the control of shoreline erosion and 

 in the emerging mariculture industry may also be found. 



