Vessel coming to area to dock (8)
I believe the answer is:
subtract
'dock' is the definition.
(I've seen this before)
'vessel coming to area' is the wordplay.
'vessel' becomes 'sub' (submarine is a type of vessel).
'coming to' is a charade indicator (letters next to each other).
'area' becomes 'tract' (tract is a kind of area).
'sub'+'tract'='SUBTRACT'
'to' is the link.
(Other definitions for subtract that I've seen before include "Take one quantity away from another" , "Withdraw" , "Deduct" , "Take an amount away" , "Knock off" .)