Mooring and Positioning of Vehioles in a Seaway 



gation frequencies out of the range of interest in the present problem, 

 the tensions and accelerations are considered adequately represented 

 by Eq, (39). 



For boom-lowered loads, the situation may be visualized by 

 reference to the accompanying sketch, where the boom length i is 



stern 



bow 



elevated at an angle a'. An appropriate value for the relevant 

 horizontal projection of the boom length (i cos o') is considered, 

 for computational purposes in the present case of a 260 ft length 

 barge, to be 150 ft, As shown below, the boom is also oriented 

 horizontally at an azimuth angle y, measured from the bow, positive 

 in the counterclockwise sense, viewed from above. The load and 



stern 



bow 



lowering-line displacements about their respective equilibrium 

 positions are given by 



s„ = X - (i cos Q'') sin Y • ^ 



s^ = y + (i cos a') cos Y * 4* 



(40) 



sX = z - (i cos a') COS "Y " 9 + (i cos a') sin y • <J) 



and the line tension (fluctuating part), T' and vertical acceleration 

 are represented by 



1035 



