Hard propping up area towards the rear (6)
I believe the answer is:
astern
'towards the rear' is the definition.
(I've seen this before)
'hard propping up area' is the wordplay.
'hard' becomes 'stern' (I've seen this in another clue).
'propping up' says to put letters next to each other (in a down clue, some letters hold others up).
'area' becomes 'a' (maths abbreviation).
'stern' after 'a' is 'ASTERN'.
(Other definitions for astern that I've seen before include "Toward the tail of a vessel" , "Toward the back of a boat" , "Backward" , "Towards back of boat" , "Towards the back (of a ship)" .)