Deliberated upon how it had capsized (6,4)
I believe the answer is:
turned over
This clue might be a double definition.
'deliberated' is the first definition.
('turn over' can be a synonym of 'deliberate')
'capsized' is the second definition.
('turn over' can be a synonym of 'capsize')
'upon how it had' is the link.
I am not very happy about this link. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for turned over that I've seen before include "Having considered carefully" , "reversed position" .)