I work with sails – it’s a fag (6)
I believe the answer is:
reefer
This clue is a double definition.
'i work with sails' is the first definition.
(someone who reefs a sail)
'a fag' is the second definition.
(I know that reefer is a type of fag)
'it's' is the link.
(Other definitions for reefer that I've seen before include "J" , "Warm jacket - cannabis cigarette" , "cold vehicle" , "refrigerated transport" , "Cigarette containing cannabis - jacket" .)