Mob means one takes this route on ship (7)
I believe the answer is:
gangway
'ship' is the definition.
(thesaurus)
'mob means' is the wordplay.
'mob' becomes 'gang' (synonyms).
'means' becomes 'way' (synonyms).
'gang'+'way'='GANGWAY'
'one takes this route on' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for gangway that I've seen before include "Way to board ship" , "means to secure passage on ship" , "Aisle between seats" , "part of ship" , "Aisle; ship access" .)