On time, vessel proceeds (6)
I believe the answer is:
return
'proceeds' is the definition.
(synonyms)
'on time vessel' is the wordplay.
'on' says to put letters next to each other.
'time' becomes 'ret' (I've seen this in other clues).
'vessel' becomes 'urn' (urn is a type of container).
'ret'+'urn' is 'RETURN'.
(Other definitions for return that I've seen before include "Come/go back" , "Give or come back" , "Comeback" , "Come back with a formal report on transactions" , "Reappear" .)