Yank; boat (3)
I believe the answer is:
tug
This clue is a double definition.
'yank' is the first definition.
(both can mean to pull sharply)
'boat' is the second definition.
(I know that tug is a type of boat)
(Other definitions for tug that I've seen before include "Pull vigorously and a boat that does it" , "water tower" , "A sharp pull or a towing boat" , "Pull a form of boat" , "draw with some effort" .)