Not a galley but may be found in one (7)
I believe the answer is:
steamer
'not a galley but' is the definition.
I can't tell whether this definition defines the answer.
'be found in one' is the wordplay.
'be' becomes 'am'.
'found in' is an insertion indicator.
'one' becomes 'steer' (I can't justify this - if you can you should believe this answer much more).
'am' going inside 'steer' is 'STEAMER'.
'may' is the link.
Can you help me to learn more?
(Other definitions for steamer that I've seen before include "Large vessel - cooking vessel" , "like the African Queen!" , "Kitchen pan; ship" , "housed in galley" , "Boat, cooking vessel" .)