Lucky breaks in a harpoon's barbs (6)
I believe the answer is:
flukes
This could be a double definition.
'lucky breaks' is the first definition.
(I've seen this in another clue)
'a harpoon's barbs' is the second definition.
'flukes' can be an answer for 'barbs' (fluke is a kind of barb). I am not sure about the 'a harpoon's' bit.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for flukes that I've seen before include "most anchors have more than one" , "Lucky accidents, or lobes of a whale's tail" , "Happy accidents" , "Unlikely pieces of luck" .)