Curves are estimates of probable moxlmum, 

 based on USWB summary of strong winds at 

 Bellingtiam, Wasti., from 1930 to 1959, 

 Wtiidby Island hourly wind record from 1949 

 to 1958, and detoiled wind record for 

 Friday Horbor from Nov. 1969 to Moy 1971. 



I 2 3 4 5 

 Duration (hr) 



Figure 18. Windspeed-duration curves, Friday Harbor, Washington. 



occurrence. Large ferries either approaching or leaving the landing, pass 

 close to the breakwater, while moving at a considerable speed. 



c. Breakwater Description. 



(1) Design and Installation . The floating breakwater at the Port 

 of Friday Harbor and the one at Tenakee Springs were the first two such struc- 

 tures of major dimension designed for the Pacific Northwest and were installed 

 at about the same time in October 1972. The Friday Harbor structure, a dif- 

 ferent type than the Alaskan ladder style, uses four rows of polyolefin pon- 

 toons about 5 by 5 by 10 feet in overall dimension, linked by a timber matrix 

 to form a 24-foot-wide section drafting about 18 inches. A simplified cross 

 section is shown in Figure 19. The breakwater is laid out in an L-shape to 

 face into the critical wind wave directions. The northeast-facing leg is 627 

 feet long (see Figs. 20 and 21); the southeast leg is 227 feet long. 



The anchor system consists of 18 pairs of anchor lines spaced about 50 

 feet apart. The lines have three sections, a 32-foot length of 7/8-inch 

 welded alloy chain attached to the breakwater, then a length of braided nylon 

 line, with another length of chain connecting to stake piles. The stake pile 

 system was chosen because of the deep, soft material at the site. The scope 

 of the seaward side is about 1 on 7; the landward side is about 1 on 2. 



The installed cost of the floating breakwater was $320 per foot (1972). 

 Those responsible for the breakwater design, construction, and operation are 

 as follows: 



35 



