Sail in a tug (3)
I believe the answer is:
lug
This clue is a double definition.
'sail' is the first definition.
(I know that lug is a type of fore-and-aft sail)
'a tug' is the second definition.
(thesaurus)
'in' is the link.
(Other definitions for lug that I've seen before include "Drag, haul" , "Projecting piece; haul" , "Drag with effort; ear" , "Drag or carry with effort" , "Pull - ear" .)