Vessel for ocean travel (5)
I believe the answer is:
canoe
'vessel' is the definition.
(canoe is a kind of vessel)
'ocean travel' is the wordplay.
'travel' indicates an anagram (I've seen 'travelled' mean this).
'ocean' with letters rearranged gives 'CANOE'.
'for' is the link.
(Other definitions for canoe that I've seen before include "Boat (that can be dug out!)" , "Light boat propelled with paddle" , "Light boat propelled by paddle(s)" , "Boat that's paddled" , "Hunting vessel originating in Haiti" .)