Secures gin on board ship (6)
I believe the answer is:
straps
'secures' is the definition.
(strapping is a kind of securing)
'gin on board ship' is the wordplay.
'gin' becomes 'trap' (I've seen this before).
'on board' means one lot of letters goes inside another.
'ship' becomes 'ss'.
'trap' inserted inside 'ss' is 'STRAPS'.
(Other definitions for straps that I've seen before include "strings" , "Lengths of leather or fabric for holding things together" , "Rail carriage handholds" , "Long pieces of lather or material for holding things" , "Ties" .)