Wave Excitationless Ships Forms 



HEAVING AMPLITUDE 



PzoH 



]2b 



0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 



% 



0.1 



0.2 0.3 



(a) a/b=2 



0.4 0.5 0.6 0.7 0.8 0.9 ^'a 



HEAVING AMPLITUDE 



+ -' 



fe5^ 



0.2 0.4 0.6 0.8 1.0 



1.2 



1.4 1.6 1.8 2.0 2.2 



10 u 



0.1 



0£ 0.3 



(b) a/b=4 



0.4 0£ 0.6 0.7 OB 0.9 



"f- 



Fig. 13 - Heaving magnification factor 

 of elliptic cylinder type models 



As shown in Fig. 15, an inner solid strut of breadth Bj is covered by a tank 

 of breadth B^. The tank is provided by small holes of total area s, depth H. 



K we denote the excitationless frequency for Bj as -o i > the heaving force 

 will vanish at frequency Wq i provided the area s is chosen adequately so that 

 the water level in the tank is always equal to that of outer surface at this 

 frequency. 



On the other hand, according to a theory of antipitching tank (12,13), the 

 movement of water in the tank, as the outer water level changes periodically, 



395 



