The ship astern has a history! (4)
I believe the answer is:
past
'a history' is the definition.
(I've seen this before)
'the ship astern has' is the wordplay.
'has' says the answer is hidden in the clue.
'PAST' is hidden within 'the ship astern'.
(Other definitions for past that I've seen before include "Days gone by" , "Bygone" , "historical times" , "Ended" , "Finished, gone" .)