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…

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 ports.

Limits the aggregate amount of loans to: (1) a specified dollar amount in a five-fiscal-year period; and (2) 50 percent of the cost of the improvements. Requires the remaining percentage to come from non-Federal sources. Prohibits loans for any activity which is eligible for assistance as a water resource project carried out by the Secretary of the Army through the Chief of Engineers.

Sets forth procedures and criteria for selection of loan recipients. Requires a set-aside of 20 percent of amounts appropriated from the Port Improvement Revolving Loan Fund each year for improvements at small deep-draft ports. Limits loans to a maximum of 20 years. Requires repayment at an interest rate which: (1) will ensure that the amount in the Fund will increase at approximately the rate of inflation; and (2) is less than market rates for such loans.

Establishes in the Treasury the Port Improvement Revolving Loan Fund, to consist of amounts: (1) transferred to the Fund equal to specified percentages of customs duties collected during specified fiscal years; (2) deposited in the Fund as repayment of loans made under this Act; and (3) credited to the Fund from interest on and proceeds from the sale or redemption of investment of amounts in the Fund.

Directs the Secretaries to establish a permanent advisory board to advise the Secretaries on matters related to this Act.