A Survey of Ship Motion Stabilization 



10 



9z 6 



FROUDE NO. = 0.08 



ROLL IN REG SEAS\ 

 TANKS OPERATIVE >v.^ 

 WITH BILGE keels/ \ 



MEAN WAVE HGT=5.2FT 



ROLL IN IRREGULAR SEAS 

 TANKS INOPERATIVE 

 ^WITHOUT BILGE KEELS 

 (FROM REF I 



MEAN WAVE HGT = 3.4FT 



roll in regular seas 

 ^ tanks inoperative 

 'without bilge keels 



from ref i 



/roll in regular SEAS 

 -< TANKS INOPERATIVE - 

 \WITH bilge KEELS 



MEAN WAVE HGT=3.8FT 



1 2 3 4 5 6 7 

 MODEL FREQ OF ENCOUNTER RAD /SEC 



I I I I I I I 1 \ I l_ 



0.2 0.4 0.6 0.8 1.0 



SHIP FREQ OF ENCOUNTER, oig , RAD /SEC 



Fig. 12 - Roll response of AGOR in 

 irregular and regular beam seas with 

 different types of stabilization 



3 different nozzle shapes were investigated to determine damping effects. Fig- 

 ure 13 indicates the general tank arrangement while Fig. 14 shows the various 

 nozzle configurations. 



The results of these experiments, Fig. 15, indicated that nozzle configura- 

 tion "A" gave the most favorable dynamic characteristics based on the more de- 

 sirable moment produced. Figure 16 shows the variation of phase angle be- 

 tween moment and roll angle with roll frequency and indicates no appreciable 

 advantage between nozzles. 



The effect of water depth is shown in Figs. 17 and 18. Generally speaking, 

 low water depth would be more advantageous at low frequencies, higher water 

 levels at the midfrequency range with no appreciable effect for either water 

 depth at high frequencies. 



765 



