According to first-order theory, a crest occurs at z = H/2, 



cos 6=1 and a trough at z = - H/2, cos = - 1. Equation 2-13 



therefore implies 



with 



and. 



with 



_ HgT cosh [27r(z + d)/L] 

 ^^'^ ~ 2L cosh(27rd/L) 



H 



z = — — 

 2 



According to second-order theory, a crest occurs at z = n o = 

 2.48 feet, cos = cos 29 = 1 and a trough at z = n^ 2 = "'l-52 

 feet, cos e = - 1, cos 20 = 1. Equation 2-51 therefore implies 



u 



HgT cosh [27r(z + d)/L] 

 '''■^ 2L cosh (27rd/L) 



+ 1 I'l^Y c cosh [47r(z + d)/L] 

 4 \L / sinh" (27rd/L) 



with 



z = Vc2 = + 2.48 feet 



and. 



"f.2 = - 



HgT cosh [27r(z + d)/L] 

 2L cosh (27rd/L) 



with 



4 \l / sinh''(27rd/L) 



z = ^^2 = ~~ 1-52 feet . 



2-43 



