F„ < 



2Hf(l - C£) n 



(55) 



Since equation (55) is an inequality, verification requires that the data plot 

 below the line be given by 



F = 4S* (56) 



n xx 



when Giles and Sorensen's (1978) data are plotted in Figure 94, they do indeed 

 fall below the inequality line, with only limited exceptions associated with 

 probable resonance near W/L = 0.5. 



Galvin and Giles (1978) concluded that measured values of mooring force 

 are consistent with the radiation stress inequality. For the case of force 

 measured in 2 meters of water, the data are remarkably linear and approxi- 

 mately equal to S* x . Force records for high waves on the floating tire 

 breakwater are consistent with the hypothesis that radiation stress exerts the 

 principal force experienced by the mooring line on the oceanside of the break- 

 water. Resonance should be expected whenever W/L is approximately 0.5, but 

 under most practical conditions, the resonant conditions do not produce the 

 maximum probable force in the mooring line. 















^ 8 modules 









300 



12 modules 



• 12 modules W / L ~ 



0.5 







2SO 



- 









200 



4 

 * / 





G 





150 



_ ^y 



A 







IOO 

 SO 

 



/ ° 

 _ • / 



** A Q 04 A & 



/ I ! I 



G 

 I 









I 



SO IOO 1SO 200 2SO 300 



Radiation Stress, 4S* (kg/m) 



Figure 94. Relationship between instantaneous peak mooring force, F , and 

 radiation stress, S* x , for the Goodyear Tire and Rubber Company 

 scrap-tire floating breakwater concept (after Galvin and Giles, 

 1978). 



142 



