Pay for communist on ship (7)
I believe the answer is:
redress
'pay' is the definition.
(I've seen this before)
'communist on ship' is the wordplay.
'communist' becomes 'red' (red is a kind of communist).
'on' becomes 're' ('on' can be mean 'with reference to').
'ship' becomes 'ss'.
'red'+'re'+'ss'='REDRESS'
'for' acts as a link.
(Other definitions for redress that I've seen before include "set things right" , "relief" , "Get back into gear" , "Correct" , "set straight again" .)