Computing Hearing and Pitching Motions 513 
HEAVING MOTION 
REAL- PART IMAGINARY - PART 
PARAMETER X/L 
g 2 
WL De 
Mins 
Pe XIE ya a ae = a Ae 
-05 -025 ) 025 05 -O5 -025 ) O25), 105 
PITCHING 
MOTION 
Up 
Upx=L/2 fe} 
Fig. 25. Heaving motion and pitching motion 
HEAVING MOTION 
0.2 
Ol IMAGINARY - PART ~,. 
REAL - PART 
A/L 
-0.2 
Ke) 0.75 0.6 OS 
3.0 | 
(Ce eae => B .[-tn-(1.783- +1)-in] = 
o cles = e ot aoa 
313 7 [ Ine (Hl.2 Xr?) in| 
I 
(eo) 
Fig. 26. Heaving motion 
In Fig. 28 the amplitude of the motion of the sections of the ship body in vertical direc- 
tion, viz., z, + w, is plotted, made nondimensional by the wave amplitude A. 
In Fig. 29 the amplitude of the deformed wave is presented, made nondimensional by 
the wave amplitude. The upper diagram holds for the restrained body and the lower diagram 
for the free moving body. The amplitudes of the wave deformed in a longitudinal direction 
are, as is expected, less reduced relative to the undisturbed wave in the case of the free 
moving ship than of the restrained ship body. These differences are, again as is expected, 
smaller in the case of small wavelengths than of large ones. The enlargement of the wave 
amplitude for A/L = 1.0 to 1.5 in the force part of the ship body in the case of the free mov- 
ing ship is striking. 
