Vessel that might be going to port (8)
I believe the answer is:
decanter
'vessel that might be going to port' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for decanter that I've seen before include "Serving bottle for liquor" , "Bottle with a stopper for wine" , "source of drink" , "Vessel with stopper for serving wine" , "quantity of wine?" .)