Vehicle back ready for battle in part of ship (7)
I believe the answer is:
yardarm
'part of ship' is the definition.
(I've seen this before)
'vehicle back ready for battle' is the wordplay.
'vehicle' becomes 'dray' (type of cart).
'back' shows that the letters should be reversed in order.
'ready for battle' becomes 'arm' (as a verb).
'dray' reversed gives 'yard'.
'yard'+'arm'='YARDARM'
'in' is the link.
(Other definitions for yardarm that I've seen before include "First drink, when sun over it" , "place of naval execution" , "Hanging place on board old ships" , "Either end of a sail beam" , "position above the deck" .)