Assistance for vessel, we hear, in covered passage (6)
I believe the answer is:
arcade
'covered passage' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for arcade that I've seen before include "Colonnade" , "shopping area" , "Covered passage containing shops" , "Lots of games" , "Covered walk with shops" .)