(a) Tolls based on net vessel tons and on displacement tonnage
Tolls on merchant vessels, army and navy transports, colliers, tankers, hospital ships, and supply ships shall be based on net vessel tons of one hundred cubic feet each of actual earning capacity, or its equivalent, determined in accordance with the rules for the measurement of vessels for the Panama Canal, and tolls on other floating craft shall be based on displacement tonnage. The tolls on vessels in ballast without passengers or cargo may be less than the tolls for vessels with passengers or cargo. Tolls for small vessels (including yachts), as defined by the Commission, may be set at rates determined by the Commission without regard to the preceding provisions of this subsection.

(b) Toll rates prescribed to cover all costs of operation and maintenance of Panama Canal
Tolls shall be prescribed at rates calculated to produce revenues to cover as nearly as practicable all costs of maintaining and operating the Panama Canal (including costs authorized to be paid from the Panama Canal Dissolution Fund under section 3714a(c) of this title), together with the facilities and appurtenances related thereto, including unrecovered costs incurred on or after October 1, 1979, interest, depreciation, working capital, payments to the Republic of Panama pursuant to paragraph 5 of Article III and paragraph 4(a) and (b) of Article XIII of the Panama Canal Treaty of 1977, and capital for plant replacement, expansion, and improvements. Tolls shall not be prescribed at rates calculated to produce revenues sufficient to cover payments to the Republic of Panama pursuant to paragraph 4(c) of Article XIII of the Panama Canal Treaty of 1977.

(c) Payment of tolls by vessels of United States
Vessels operated by the United States, including vessels of war and auxiliary vessels, and ocean-going training ships owned by the United States and operated by State nautical schools, shall pay tolls.

(d) Levy of tolls
The levy of tolls is subject to the provisions of section 1 of Article III of the treaty between the United States of America and Great Britain signed November 18, 1901, of Article I of the treaty between the United States of America and the Republic of Colombia signed April 6, 1914, and of Articles II, III, and VI of the Treaty Concerning Permanent Neutrality and Operation of the Panama Canal, between the United States of America and the Republic of Panama, signed September 7, 1977.