Ochi 



For a better understanding of the relationship between slamming and rela- 

 tive motion, Fig. 3 was prepared. Figure 3(a) is an explanatory figure showing 

 time history of relative motion. At the instant of a slam as the bow re-enters 

 the water, the relative motion r(t) must be positive and equal to h. The rela- 

 tive velocity r(t) at this instant is negative and its absolute value must be 

 greater than the threshold velocity, f*. The above condition is given on the 

 phase-plane diagram shown in Fig. 3(b). 



RELATIVE 

 MOTION {*r) 



RELATIVE 

 MOTION (♦r) 



RELATIVE 

 VELOCITY (+r) 



(b) 



Fig. 3 - Explanatory sketch of time 

 history of relative motion and phase - 

 plane diagram 



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