Salvesen 



R = 4 Pg ^ 



(38) 



where H is the wave height obtained from the second-order wave theory. This 

 is exactly the same result as obtained in Appendix A using a second-order 

 Stokes wave theory. 



A plot of the first-order and the second-order wave resistance is seen in 

 Fig. 6, where the first-order resistance is obtained from the well-known rela- 

 tionship 



R = -^PE<^' 



(39) 



with a denoting the first-order wave amplitude far downstream. Again we see 

 the large difference between the first-order and the second-order theory for the 

 lower speed range. 



- 



25 30 



ft/sec 



/ 



^ 0.3 



./. 



^ 



/ 



f 



n 



h 



v 



l- 



t- 



T- 



/ 



FIRST ORDER 



SECOND ORDER 



3 4 5 

 SPEED U, ff/sec 



Fig. 6 - First-order and second-order wave 

 resistance curves for 1.25-ft submergence 



608 



