Ships that ply on a regular scheduled service between groups of ports. The ships of a liner Company are common carriers, offering cargo space or passenger accommodation to all shippers and passengers who require them. A Liner Company is generally engaged on trade routes where volume of cargo or passenger traffic is available. Liner Conference : An organization whereby a number of ship owners offer services on given sea routes on conditions agreed by the members. A conference line ship is a vessel or a ship belonging to a member of such shipping conference.