Throws fish in ship (6)
I believe the answer is:
slings
'throws' is the definition.
(I've seen this in another clue)
'fish in ship' is the wordplay.
'fish' becomes 'ling' (ling is a kind of fish).
'in' indicates putting letters inside.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'ling' put into 'ss' is 'SLINGS'.
(Other definitions for slings that I've seen before include "Looped bandages for limb support or missile throwers" , "'''... to suffer the ... and arrows of outrageous fortune'' (Hamlet) (6)'" , "Supporters" , "Arm bandages; drinks" , "Catapults or arm supports" .)