Change course, finding security device (4)
I believe the answer is:
tack
This could be a double definition.
'change course' is the first definition.
(I've seen this in another clue)
'security device' is the second definition.
'tack' can be an answer for 'device' (tack is a kind of device). I'm unsure of the 'security' bit.
'finding' is the link.
Can you help me to learn more?
(Other definitions for tack that I've seen before include "Fix with pins, shoddy material" , "Food; nail" , "Nail; course of action" , "Drawing-pin" , "(Of a sailing ship) alter course through the wind" .)