The necessity for the replacement of vessels owned by the United States and in the possession or under the control of the Secretary of Transportation and the construction for the Secretary of Transportation of additional up-to-date cargo, combination cargo and passenger, and passenger ships, to give the United States an adequate merchant marine, is recognized, and the Secretary of Transportation is authorized and directed to present to Congress from time to time, recommendations setting forth what new vessels are required for permanent operation under the United States flag in foreign trade, and the estimated cost thereof, to the end that Congress may, from time to time, make provision for replacements and additions. All vessels built for the Secretary of Transportation shall be built in the United States, and they shall be planned with reference to their possible usefulness as auxiliaries to the naval and military services of the United States.