He contends he knows something about boats (5)
I believe the answer is:
rower
This clue could be a double definition.
'he contends' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he knows something about boats' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
Can you help me to learn more?
(Other definitions for rower that I've seen before include "Oarsman/oarswoman" , "Might one argue" , "Person using 9" , "crew member, perhaps" , "Perhaps stroke" .)