Sailors consumed by ship's propellers (6)
I believe the answer is:
screws
'propellers' is the definition.
(screw is a kind of propeller)
'sailors consumed by ship's' is the wordplay.
'sailors' becomes 'crew' (I've seen this before).
'consumed by' is an insertion indicator.
'ship' becomes 'ss'.
'crew' going into 'ss' is 'SCREWS'.
(Other definitions for screws that I've seen before include "increase the pressure" , "Prisoner guards, colloquially" , "Grooved type of nails" , "Fastner with spiral thread" , "Fastening devices and prison guards, colloquially" .)