Russian port’s odd, turning fellow sailors back ultimately (8)
I believe the answer is:
murmansk
'russian port's' is the definition.
'odd turning fellow sailors back ultimately' is the wordplay.
'odd' becomes 'rum' (I've seen this before).
'turning' shows that the letters should be reversed in order.
'fellow sailors' becomes 'mans' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ultimately' says to take the final letters.
The last letter of 'back' is 'k'.
'rum' backwards is 'mur'.
'mur'+'mans'+'k'='MURMANSK'
(Other definitions for murmansk that I've seen before include "Port in the Arctic Circle" , "Largest town north of the Arctic Circle" , "Sea port in NW Russia" , "Port of north-western Russia" .)