1) Merchant ship fee 2) Port duty 
• (n.) The right of demanding a duty or toll for a ship entering a port; also, the duty or toll.
Keel'age noun [ Confer French guillage , from guille keel; of German or Scand origin. See 3d Keel .] The right of demanding a duty or toll for a ship entering a port; also, the duty or toll. Bouvier. Wharton. 
Keelage is a fee paid by the owners of a ship for being permitted to dock in certain ports and harbours.
a toll on a merchant ship entering a port.