bottom slope and bottom conditions; 6- to 8-ton steel anchors would have 

 been much better. Special receptacles for navigation lights should be 

 designed into the breakwater units. 



The following comments on the design and installation of the floating 

 breakwater were provided by the U.S. Army Engineer District, Alaska: 



Use epoxy coatings over steel reinforcement to reduce corro- 

 sion. Provide positive locking devices at the ends of connecting 

 cables. Obtain sufficient bottom data to allow workable anchorage 

 designs . Some problems with anchor placement were experienced owing 

 to a lack of good topography and knowledge of what materials the 

 anchors would be set on. Consideration should be given to providing 

 a method of regreasing tendons and cables. This design was made with 

 the premise that vessels would not be allowed to tie up to the break- 

 water. The design must provide heavy wales and recessed bolts to 

 allow for protection of the breakwater from vessels that tie up tem- 

 porarily. Provide for connections on end units for possible future 

 changes in configuration. These can be temporarily sealed with 

 knockouts. Adequate lighting should be provided for foul weather 

 visibility of the breakwater to supplement U.S. Coast Guard furnished 

 lights. Radar visibility should also be provided. Better quality 

 control should be achieved to eliminate careless slopping of grease 

 on concrete surfaces adjacent to the prestressed cable anchors. Pre- 

 paration of construction specifications should consider the require- 

 ment for a specific assembly method, such as on a sinkable barge, or 

 in the water, or in a dredged area which can be flooded. Materials 

 and procedures used should be compatible with the assembly method. 

 Construction problems were experienced during the process of capping 

 the prestress cable heads in the water. Further consideration might 

 be given to a cofferdam design which would allow this to be accom- 

 plished in the dry. Consideration should be given to monitoring 

 anchor chains to determine actual mooring forces to compare with 

 design forces. 



(3) Performance. The boat slips had not been installed as of Sep- 

 tember 1980, so there are no data on breakwater effectiveness. The harbormas- 

 ter expressed the opinion that the breakwater does perform as expected. Pre- 

 vailing wind waves attacking the breakwater are at a high incident angle, and 

 the alinement seems good, with lower transmission than for normally incident 

 waves. 



The installer (B. Smart) was on a barge tied to the breakwater during a 

 storm with gusts up to 70 knots. Ife reported wave periods of 3.5 to 4 seconds 

 and wave heights to 4 feet, based on the height of the barge rail above mean 

 water level: "... the breakwater really knocked the waves down." Three 

 wavelengths were observed in the 100-foot barge length, which would correspond 

 to about a 2.7-second period, rather than the 3 to 4 seconds reported. 



Logs up to 2 feet in diameter have worked their way into the interior 

 spaces of the breakwater, but have conveniently worked their way out. There 

 has been rapid marine growth on the submerged surfaces. 



14 



