Evaluation of Motions of Marine Craft in Irregular Seas 



90 



60 



Q 30- 



«O330 



300 



PHASE definition: 

 WAVE ELEVATION: 

 ROLL ANGLE 



77 • T7g cos wf 



e • 0„cos(wt- S) 



I I 1 1 / 1 1 1 1 1 I ►- 



W, ENCOUNTER FREQUENCY, RADIANS/SECOND 



Fig. 7 - Roll transfer function for 

 submerged body in beam seas 



P(a)) = A(a;)^ cos W{oS)] 



^ COS < 



2V 



tan" 



2^' 



> (67) 



and 



485 



