Babe about to join ship will become superior lady (6)
I believe the answer is:
abbess
'superior lady' is the definition.
(I've seen this before)
'babe about to join ship' is the wordplay.
'about' indicates an anagram.
'to join' means one lot of letters go next to another.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'babe' anagrammed gives 'abbe'.
'abbe'+'ss'='ABBESS'
'will become' acts as a link.
(Other definitions for abbess that I've seen before include "Mother superior" , "superior lady" , "Head nun" , "superior to her sisters!" , "woman trying to be religious?" .)