449 names of all the States are in use, a battleship may be named for a city, place, or person. (c) The Secretary of the Navy may change the name of any vessel bought for the Navy. § 7293. Number in service in time of peace In time of peace, the President may keep in service such vessels of the Navy as are required and keep the rest in reserve. § 7294. Suspension of construction in case of treaty I n case of a treaty for the limitation of naval armament to which the United States is a signatory, the President may suspend so much of the authorized naval construction as is necessary to bring the naval vessels of the United States within the limitations agreed upon. Such a suspension does not apply to vessels under construction at the time the suspension is made. §7295. Vessels: under-age Vessels of the following types are considered under-age for the period after completion indicated below: (1) Battleships—26 years. (2) Aircraft carriers—20 years. (3) Cruisers—20 years. (4) Submarines—13 years. (5) Other combatant surface vessels—16 years. § 7296. Appropriations: available for other purposes Appropriations available for the construction or conversion of vessels or their machinery, armament, and equipment may be used for any of those purposes. These appropriations for auxiliary vessels may also be used for acquisition of those vessels. §7297. Changing category or type: limitations Unless they have been specifically made available for the purpose, funds appropriated for the repair or alteration of naval vessels may not be used to make repairs or alterations of any vessel that would change its category or type. § 7298. Conversion of combatants and auxiliaries To improve the military characteristics of combatant and auxiliary naval vessels, the President may convert such vessels as he considers best suited for national defense, without limitation on expenditures for any one vessel, but within the total sum appropriated for conversion of vessels. § 7299. Contracts: application of Public Contracts Act Each contract for the construction, alteration, furnishing, or equipping of a naval vessel is subject to the Act of June 30, 1936, ch. 881 (48 Stat. 2036), before amendment, unless the President determines that this requirement is not in the interest of national defense.