Reportedly crucial place for loading and unloading ships (4)
I believe the answer is:
quay
'place for loading and unloading ships' is the definition.
'reportedly crucial' is the wordplay.
'reportedly' shows a homophone (sound like).
'crucial' becomes 'key' (I've seen this in another clue).
'key' is a homophone of 'QUAY'.
(Other definitions for quay that I've seen before include "Dock, wharf" , "Some of port" , "Landing area" , "Jetty" , "Pier" .)