Couple run around new steamship (7)
I believe the answer is:
harness
'couple' is the definition.
(I've seen this before)
'run around new steamship' is the wordplay.
'run' becomes 'hare' (hare can mean to run very fast).
'around' is an insertion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'steamship' becomes 'ss' (nautical abbreviation).
'hare' going around 'n' is 'harne'.
'harne'+'ss'='HARNESS'
(Other definitions for harness that I've seen before include "Leather straps on a draft animal" , "Control; trappings" , "Restraint" , "Rein in" , "Control and exploit" .)