Room on Irish ship for engineer's passage (6)
I believe the answer is:
leeway
'room on irish ship' is the definition.
'leeway' can be an answer for 'room' (both can mean freedom or space to move or act). I am not sure about the 'on irish ship' bit.
'engineer's passage' is the wordplay.
'engineer's' becomes 'lee' (I can't justify this - if you can you should believe this answer much more).
'passage' becomes 'way' (I've seen this in other clues).
'lee'+'way'='LEEWAY'
'for' is the link.
Can you help me to learn more?
(Other definitions for leeway that I've seen before include "Slack" , "Room to manoeuvre, as for a ship" , "Drift to make up" , "Limited room for manoeuvre" , "Amount of freedom" .)