Sailing on her river (5)
I believe the answer is:
rhone
'river' is the definition.
(I know that Rhone is a river)
'sailing on her' is the wordplay.
'on her' can be anagrammed to 'RHONE'.
Though, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for rhone that I've seen before include "wherein runs rain in Arbroath" , "French river from Alps to Mediterranean" , "European river and glacier" , "River running from the Swiss Alps to the Mediterranean" , "wine-producing area" .)