Nothing's caught by rod in boat (5)
I believe the answer is:
canoe
'boat' is the definition.
(canoe is a kind of boat)
'nothing's caught by rod' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'caught by' means one lot of letters goes inside another.
'rod' becomes 'cane' (I've seen this in other clues).
'o' placed into 'cane' is 'CANOE'.
'in' is the link.
(Other definitions for canoe that I've seen before include "Simple boat" , "Light boat propelled with paddle" , "River craft" , "Kayak, for instance" , "Light, narrow open boat" .)