46 U.S.C. § 57105: Acquisition of vessels for essential services, routes, or lines

the Secretary considers the vessel necessary to establish, maintain, improve, or serve as a replacement on an essential service, route, or line in the foreign commerce of the United States, as determined under section 50103 of this title ; the vessel was constructed in the United States; and the Secretary of the Navy has certified to the Secretary of Transportation that the vessel is suitable for economical and speedy conversion into a naval or military auxiliary or otherwise suitable for use by the United States Government in time of war or national emergency. The price paid for the vessel shall be based on a fair and reasonable valuation. However, the price may not exceed by more than 5 percent the cost of the vessel to the owner (excluding any construction-differential subsidy and the cost of national defense features paid by the Secretary of Transportation) plus the actual cost previously expended for reconditioning, less depreciation based on a 25-year life for a dry-cargo or passenger vessel and a 20-year life for a tanker or other liquid bulk carrier vessel. A vessel acquired under this section that is not documented under the laws of the United States at the time of acquisition shall be so documented as soon as practicable.