Manipulating tackle (7)
I believe the answer is:
rigging
This clue is a double definition.
'manipulating' is the first definition.
('rig' can be a synonym of 'manipulate')
'tackle' is the second definition.
('rigging' can be a synonym of 'tackle')
(Other definitions for rigging that I've seen before include "Manipulation" , "falsifying of votes in election" , "Sailing ship's ropes" , "part of craft?" , "Formation of masts etc. on a vessel" .)