Site: 









LAKE BARKLEY 









FB 





FB 

























Marina 



N 







4 



1— 







■■ I 



10 



™1 



20m 











Special Equipment: A Corps of Engineers mooring sign is positioned atop each 

 module to warn boaters of the mooring cables. 



Field Experience 



Operation: Structural failure is cited as a moderate problem with corrosion 

 and coupling failure posing minor difficulties. To counter these 

 problems, the operator reinforced the steel frame, thereby improving the 

 structural integrity of the FB. Anchoring system failure was also 

 regarded as a moderate problem with mooring line failure being a minor 

 one. In response to these troubles, the operator increased the scope of 

 the mooring lines. Fouling growth also is considered a minor problem. 

 Under worst storm conditions with waves 0.9 m (3.0 ft) in height and 6.4 m 

 (21.0 ft) in estimated length, the tranmission coefficient is 0.33. 



Maintenance: Scheduled maintenance includes checking for loose bolts and 

 inspecting the mooring lines. 



Cost: The total construction cost of the two modules was $10,000. This figure 

 translates to a cost of $388.66/m 2 ($36.10/ft 2 ) in 1980 dollars. 



Benefits: The operator felt that the breakwater had a positive effect on 



boaters' comfort. He rated the FB as providing moderate performance in 

 suppressing waves and meeting design goals and poor performance in 

 satisfying his needs. Overall performance was rated moderate. 



Project Analysis: The utility of this design appears limited to freshwater 



sites with modest wave conditions. Effectively, this structure is a small 

 floating steel dock with a cost tremendously higher than that of scrap 

 tire or wood FBs. By proper reinforcement, the frame can be made to 

 withstand most wave forces. Also, a more conventional anchoring system 

 can probably eliminate any further troubles with this aspect of the 

 system. Therefore, the difficulties now being experienced can be 

 resolved. One other problem will still remain, however, and that is the 

 ease with which waves can diffract around and through the modules. The 

 quick answer to this problem is to extend and connect the modules, but 

 because of the high cost of the system, it would probably prove more 

 cost-effective to examine alternative FB designs. 



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