Naval officer has something to go on, gathering men (9)
I believe the answer is:
commodore
'naval officer' is the definition.
(I've seen this before)
'something to go on gathering men' is the wordplay.
'something to go on' becomes 'commode' (I can't explain this - if you can you should give a lot more credence to this answer).
'gathering' indicates putting letters inside (gather can mean to acquire or bring in).
'men' becomes 'OR' (Other Ranks: non-commissioned soldiers).
'commode' enclosing 'or' is 'COMMODORE'.
'has' is the link.
Can you help me to learn more?
(Other definitions for commodore that I've seen before include "Naval officer" , "senior officer" , "officer, surely?" , "Naval rank junior to rear-admiral" , "President of a yacht club" .)