were measured at station 40.0 and transmitted wave heights were measured 

 8.3 meters (27.2 feet) behind each test structure (i.e., at stations 72.7 

 and 77.3 for the 8- and 12-module tests, respectively). Mooring forces 

 were measured at station 32.0 with the load cell mounted above the water 

 surface midway over the top of the tank (Figs. 7 and 9). 



The seaward (generator side) of the breakwater was moored using a 

 single mooring line secured on a 1 on 7 slope. The mooring line was made 

 from 6 meters (19.7 feet) of open-link chain and 0.48-centimeter (0.187 

 inch) stainless steel cable. It was fastened to the breakwater by form- 

 ing a yoke between the two front modules similar to the connection used 

 in field installations. The shoreward (absorber beach) side of the struc- 

 ture was moored using 0. 24- centimeter (0.094 inch) stainless steel cable 

 and 6 meters of open- link chain attached to each of the rear modules. 



Each mooring line was threaded through a pulley (Fig. 10) secured 

 to the tank floor. The line was then attached to a load cell (Fig. 9) 

 located directly overhead. During the first series of tests, using the 

 eight-module structure in 4 meters of water, a 2,000-pound (907 kilograms) 

 load cell was attached to the right rear anchor line. This cell did not 

 accurately measure loads less than 100 pounds (45.4 kilograms) because 

 of the lack of adequate signal resolution; subsequently, the load cell 

 was removed when modifications to the test section were made. 



Tank limitations and the anchor locations during the series of tests 

 conducted with a 2-meter water depth indicated a requirement that the 

 front mooring line be secured on a 1 on 10 slope. Both of the mooring 

 line slopes (1 on 7 and 1 on 10) were within the range of slopes used in 

 field installations. 



3. Test Procedure . 



Each breakwater section was tested using wave conditions commonly 

 found on a sheltered body of water such as a reservoir or bay. A total 

 of 165 combinations of wave period, wave height, structure width, and 

 water depth was tested. Wave periods ranged from 2.64 to 8.25 seconds. 

 Wave heights varied from 20 to 140 centimeters (0.66 to 4.59 feet). 

 Water depths of 2 and 4 meters were used: the 2-meter depth with the 

 12-module unit and the 4-meter depth with both the 8- and 12-module units. 



Each combination of wave height,, wave period, water depth, and struc- 

 ture width was tested for 5 minutes. This allowed sufficient time to 

 determine the average mooring force loads and the incident and trans- 

 mitted wave heights. Selected wave conditions were repeated during the 

 study to determine the repeatability of mooring force and wave height 

 measurements . 



4. Difficulties Encountered During Tests . 



Because each test duration was 5 minutes, reflections from the break- 

 water and the absorber beach were re-reflected from the breakwater and 



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