Sailor has bath outside in river (6)

I believe the answer is:

wabash

'river' is the definition.
(I know that Wabash is a river)

'sailor has bath outside' is the wordplay.
'sailor has' becomes 'ba' (I am not sure about this - if you are sure you should believe this answer much more).
'bath' becomes 'wash' (I've seen this before).
'outside' is an insertion indicator.
'ba' inserted into 'wash' is 'WABASH'.

'in' is the link.

(Another definition for wabash that I've seen is " River".)

I've seen this clue in The Guardian.

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