Ships in a drama, unconventional (6)
I believe the answer is:
armada
'ships' is the definition.
(group of ships)
'a drama unconventional' is the wordplay.
'unconventional' is an anagram indicator.
'drama' anagrammed gives 'rmada'.
'a'+'rmada'='ARMADA'
'in' acts as a link.
(Other definitions for armada that I've seen before include "Spanish war fleet" , "Old Spanish fleet" , "A great fleet, ships or planes" , "Many ships" , "Spanish fleet sent in 1588 to escort an invasion of England" .)