Ten 3.0-m (10.0 ft) steel fingers extend from the pipe and grasp the 4-inch 

 diameter spudpoles by means of 0.9-m (3.0 ft) -long brackets made from 5-inch 

 pipe. 



Site: 



Installation: The breakwater is free to slide up and down the spudpoles. Ten 



spudpoles are positioned on the leeward side of the structure at 12.2-m 



(40.0 ft) intervals. There is also a spudpole at each end of the 

 breakwater. 



Field Experience 



Operation: The primary difficulty encountered by this design has been the 



habit of the structure to get caught upon and bend the spudpoles. This 

 has led to moderate problems of instability, structural failure, and 

 coupling (i.e., bracket) failure. If given the opportunity to rebuild the 

 structure, the operator would add a matching set of fingers, brackets, and 

 spudpoles on the exposed side to balance the mooring forces. Corrosion is 

 also cited as a moderate problem. Collision damage, interference with 

 boating traffic, ice damage, anchoring system (i.e., spudpole) failure, and 

 litter entrapment all pose minor problems to the operation of this FB. 

 Under typical storm conditions with waves 1.1 m (3.5 ft) in height and 

 20.0 m (65.5 ft) in estimated length, the transmission coefficient is 

 0.43. No significant deterioration in performance has been seen over the 

 years. 



Maintenance: Scheduled maintenance consists of checking the spudpoles and 

 straightening those that have bent. 



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

 preventing shoreline erosion, improving waterfront appearance and 

 providing boaters' comfort. He believed that the structure had a negative 

 effect on sediment movement. He rated the FB as providing high 

 performance in suppressing waves and moderate performance in meeting 

 design goals and satisfying his needs. Overall performance was rated 

 high. 



73 



