Heavy Sterncastles frenzy ~

I used to plunder 1 or with very much luck 2 Heavy sterns from conquerors in a entire day, but that day was.. maybe rare? Why!?
5 Heavy Sterns in few hours, priceless, using 13+3 plunder rank.... crazy (◎_◎;)..
I don't know if this is normal or maybe some other guy plundered 10 in a same day already lol. But this is my personal record for now <3 ~

＼(^o^)／ I hope the same luck the next time ~