of wave periods (0.75 to 2.5 seconds) and heights 0.03 to 0.30 meter 

 (0.1 to 1.0 foot) at water depths of 0.30 and 0.61 meter (1 and 2 feet). 

 In addition to usual Reynolds niomber scale effects involved in tests at 

 reduced scale, the mooring load and transmission results obtained in 

 their study may also have suffered scale problems due to the decreased 

 flexibility of the rigid model tires in comparison to the greater flexi- 

 bility of prototype automobile and truck tires. 



Kowalski (19 74) reported a brief field investigation of the wave 

 transmission characteristics of a "mat-type" FTB made up of three layers 

 of tires lying flat and strapped together to yield the dimensions 15.2 

 by 15.2 by 0.46 meters (50 by 50 by 1.5 feet). Two sets of wave measure- 

 ments were made using a pair of wave gages, one placed seaward and the 

 other shoreward of the FTB. -The incident waves had significant heights 

 of 0.8 and 0.9 meter (2.5 and 3.0 feet) and significant periods of 2.0 

 and 1.8 seconds, respectively. No mooring forces were measured. 



Sucato (1975) conducted a brief field test using a module FTB proposed 

 by Goodyear Tire and Rubber Co., with overall dimensions of approximately 

 25.6 by 5.9 by 0.8 meters (84 by 19.5 by 2.5 feet). Wave transmission and 

 mooring loads were evaluated for an incident wave condition having a 

 significant wave height of 0.46 meter (1.5 feet) and a significant period 

 of 2.2 seconds. Sucato compared the effectiveness of this breakwater to 

 the one used by Kowalski (1974) and found that the Goodyear module- type 

 FTB was more effective in attenuating waves. He also found the mooring 

 loads were less for the Goodyear FTB than for the mat-type FTB. Since 

 loading is cyclic he speculated that premature failure due to creep could 

 occur. 



This study measures wave transmission and mooring load characteristics 

 at prototype scale for an FTB constructed of tires arranged in one of the 

 modular forms being used at several locations in coastal waters. Using 

 an 18-tire module arrangement proposed by the Goodyear Tire and Rubber 

 Co. (Candle and Fischer, 1977), breakwaters that were 4 and 6 modules 

 (8.5 and 12.8 meters, 28 and 42 feet) in the direction of wave advance 

 were tested in water 2 and 4 meters (6.56 and 13.12 feet) deep for a 

 range of wave conditions. Tests were conducted in the large wave tank 

 at the Coastal Engineering Research Center (CERC) . This report describes 

 the FTB characteristics typical of a field installation, the experimental 

 setup in the large wave tank, experimental procedures, data reduction 

 techniques, and the results obtained. Experimental results and their 

 application to the design of FTB's for field installation are discussed. 



II. THE GOODYEAR FLOATING TIRE BREAKWATER SYSTEM 



1. Breakwater Components . 



The Goodyear floating tire breakwater uses a modular construction 

 concept. Eighteen 14- or 15-inch (36.6 or 38.1 centimeters) standard 

 automobile tires are tied together to form a basic 1.98- by 2.13- by 

 0.76-meter (6.5 by 7.0 by 2.5 feet) module. Individual modules are then 

 joined to form a floating breakwater of desired length, t, and width, W. 



