46 U.S.C. § 50102: Survey of merchant marine

an adequate and well-balanced merchant fleet, including vessels of all types, that will provide shipping service essential for maintaining the flow of foreign commerce by vessels designed to be readily and quickly convertible into transport and supply vessels in a time of national emergency; ownership and operation of the fleet by citizens of the United States insofar as practicable; vessels designed to afford the best and most complete protection for passengers and crew against fire and all marine perils; and an efficient capacity for building and repairing vessels in the United States with an adequate number of skilled personnel to provide an adequate mobilization base. In carrying out subsection (a)(1), the Secretary of Transportation shall cooperate closely with the Secretary of the Navy as to national defense requirements.