^P = wZ/2 +W ^^-'^ 



where D = C^p A^ P V^/Z, current drag force on payload 

 D„ = Cj£ dj^ p v2/2, unit current drag on lift line 



Z = distance from the surface 



w = submerged weight of the lift line per foot 



W = submerged weight of the payload 

 Cj = drag coefficient 



A = drag cross-sectional area 

 d£ = lift line diameter 



p = density of water 



V = current velocity 



Subscripts p and i distinguish payload from lift line. The displacement 

 of a point on the guideline Z feet below the surface due to the offset of 

 the guideline anchor is: 



^go " ^go ^/^max 



where subscript g indicates the guideline. Superimposed on this displace- 

 ment is the displacement Z due to the current drag. Because the tension 

 in the guideline will be generally high when compared with the total sub- 

 merged weight of the guideline, the weight of the guideline is neglected. 

 Reference is made to Figure A-3: using parabolic cable approximation, the 

 maximum displacement of the guideline is at mid-depth. 



Lgc = Dg Z^^^/8 T, (A-2) 



where the unit drag force on guideline is 



Dg = Cdg dg p v2/2 



and d„ is the guideline diameter. The current induced guideline displace- 

 ment at upper half of the line is: 



28 



