Seat moved, by sailors, towards the rear (6)
I believe the answer is:
astern
'towards the rear' is the definition.
(I've seen this before)
'seat moved by sailors' is the wordplay.
'moved' is an anagram indicator.
'by' says to put letters next to each other.
'sailors' becomes 'RN' (abbreviation for Royal Navy).
'seat' with letters rearranged gives 'aste'.
'aste'+'rn'='ASTERN'
(Other definitions for astern that I've seen before include "at the vessel's rear" , "following behind vessel" , "back for sailors" , "Backward" , "Aft" .)