Another chess victory for the ship's officer (6,4)

I believe the answer is:

second mate

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'the ship's officer' is the definition.
(another term for the second officer of a ship)

'another chess victory' is the wordplay.
'another' becomes 'second'.
'chess victory' becomes 'mate' (I can't justify this - if you can you should give a lot more credence to this answer).
'second'+'mate'='SECOND MATE'

'for' is the link.

Can you help me to learn more?

(Other definitions for second mate that I've seen before include "Craftsman, perhaps" , "Naval officer" , "one involved in bigamy?" .)

I've seen this clue in The Globe and Mail.

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