A Survey of Ship Motion Stabilization 



shown in Fig. 21 while the variation of phase angle between moment and roll is 

 shown in Fig. 22. The general conclusions arrived at from these experiments 

 are in agreement with those reached in previous tests. There appears to be no 

 unexpected adverse effect from putting the tanks below the roll axis. 



400 



300 — 



200 



100 — 



0.1 



0.2 0.3 0.4 0.5 



MODEL ROLL FREQ IN GPS 



0.6 



.0229 



.0459 



.0688 



.0918 



.1147 



.1376 



Fig. 21 - Tank moment as a function of 

 roll frequency 3, 4, and 5 foot water 

 levels at 2 degrees roll amplitude 



USS BRONSTEIN- Active Fins. The USS BRONSTEIN (DE 1037) is a 350- 

 foot ASW vessel of 2500 tons displacement. This ship is fitted with active anti- 

 rolling fins that are fixed in the out-rigged position. In other respects this in- 

 stallation is similar to that of the USS GYATT [43]. 



Forced roll experiments were performed on this ship during the sea trials 

 conducted early in 1964. Figure 23 shows the comparison of the stabilized and 

 unstabilized roll quenching capability. Figure 24 compares the roll angle enve- 

 lopes for the stabilized and unstabilized conditions and it may be seen that the 

 damping of the stabilized curve is approximately 3 times that of the unstabilized 

 curve. 



773 



