constructed of marine plywood, galvanized sheet steel, and Styrofoam to allow 

 better reproduction of the floating and dynamic characteristics of the break- 

 waters. Model design calculations included all the major materials used in 

 the prototype modules, i.e., concrete, polystyrene, and posttensioned steel, 

 but did not include the anchor-chain hardware connections and the bumper 

 material between the modules because their proposed weight would be negligible 

 in the overall . considerations. The model structures floated within 0.10 foot 

 prototype of the proposed structure. 



All plans were tested with 72-foot-long anchor chains. The prototype 

 chain, weighing 14.2 pounds per linear foot, was reproduced in the model by 

 U.S. No. 1 double-link, chain which had an approximate weight of 0.14 pound per 

 linear foot, thus providing proper undistorted Froudian scaling. Tests were 

 conducted in a flat-bottomed wave basin about 56 feet wide and 90 feet long 

 (Fig. 22). A semiportable wall was used to create flume widths of 10 and 12.4 

 feet for two-dimensional tests and 35.5 feet for three-dimensional tests. 

 Fibrous wave absorber was placed in the ends of the flume to dissipate wave 

 energy that might otherwise be reflected from the model walls. Waves were 

 generated by a 35.5-foot-long horizontal-displacement wave generator. 



< ' — TVO-DIMENSIONAl. TEST SECTIONS 



SEMI PORTABLE WALL LOCATIONS FOB TWO-DIMENSIONAL TESTS 



SEHIPORTABLE WALL LOCATION TOR THREE-DIMENSIONAL TESTS 



* 1 -— WAVE ABSORBER 



Figure 22. Physical model test facility for wave attenuation effectiveness 

 of single-pontoon floating breakwater proposed for Olyrapia Harbor, 

 Washington (after Carver, 1979). 



Carver (1979) evaluated three single-pontoon floats. Specific details of 

 the various plans were as follows: 



(a) Plan 1 was a 12- by 96-foot rectangular float with a draft of 

 3.5 feet. The prototype structure weighed 258,000 pounds and had a 

 unit weight of 44.8 pounds per cubic foot. Plan 1 was modeled with a 

 uniform cross-sectional structure, 1.2 feet wide by 9.6 feet long, 

 weighing 252 pounds with a unit weight of 43.7 pounds per cubic foot. 



(b) Plan 1A was identical to Plan 1 except a 3. 5-foot-high 

 vertical-barrier plate was added to the bottom of the structure's 

 seaward face. 



54 



