Boatman who has secret watch with silver lining (8)

I believe the answer is:

voyageur

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'boatman who has secret' is the definition.
'voyageur' can be an answer for 'boatman' (I have seen 'Canadian boatman ' mean 'voyageur' so perhaps 'boatman' could also mean 'voyageur'). I am unsure of the rest of the definition.

'watch with silver lining' is the wordplay.
'watch with' becomes 'voyeur' (I can't explain this - if you can you should believe this answer much more).
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'lining' is an insertion indicator.
'voyeur' going around 'ag' is 'VOYAGEUR'.

Can you help me to learn more?

(Another definition for voyageur that I've seen is " Canadian boatman".)

I've seen this clue in The Times.

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