Ship one's breaking (9)
I believe the answer is:
destroyer
This clue is a double definition.
'ship' is the first definition.
(I know that destroyer is a type of combat ship)
'one's breaking' is the second definition.
(something that destroys/breaks things)
(Other definitions for destroyer that I've seen before include "Naval ship" , "Small, fast warship" , "Saboteur" , "HMS" , "Naval vessel" .)