Ghostshells and Ghostships, never seen them so far, over 100 games CAT and over 100 games in CBT.
With battleship i´ve survived over 8 torp hit in same time, took only allmost half hp down.
This dmg was also in CAT not only in CBT.
15k dmg deals usually then, when it does critical hit, not normal dmg, Once i did 1 shell dmg over 27k (with amagi). and sometimes i do with 6 shell hit less then 200. Its meybe because you do not hit some critical spot.
but yea, why should go to CAT if its in TEST phrase and usually what ppl does in here is test and report about bugs if there is some. One good avice record your gameplays and when u rly see some ghostship then u got prove at last