To amend the Maritime Act of 1981 to enhance interstate and foreign commerce and improve competitiveness of United States ports in such commerce by establishing a port improvement revolving loan program to be administered jointly by the Secretary of Commerce and the Secretary of Transportation.

Redesignates the Maritime Act of 1981 as the Maritime Act of 1991 and adds a new title: the Port Improvement Act of 1991. Directs the Secretary of Transportation, through the Federal Maritime Administration and the Secretary of Commerce (the Secretaries), to jointly establish a program to make loans to port agencies for financing and refinancing improvements to facilities at deep-draft...