A vessel associated with port containerisation! (4,8)
I believe the answer is:
wine decanter
'a vessel associated with port containerisation' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'vessel associated with port containerisation' is the wordplay.
I cannot really understand how this works, but
'vessel' could be 'decanter' (decanter is a kind of vessel) and 'decanter' is found within the answer.
'with' could be 'w' (abbreviation) and 'w' is found within the answer.
The remaining letters 'ine' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for wine decanter that I've seen is " for the port, perhaps".)