A bill to encourage improvement in the energy efficiency of propulsion systems used by United States flag merchant vessels and for other purposes.

[AI summary unavailable — showing source text] Amends the Merchant Marine Act, 1936, to authorize the Secretary of Commerce to make construction-differential subsidies available to United States built or documented vessels for replacement or upgrading of such vessels' existing propulsion machinery in order to improve energy efficiency. Establishes guidelines for the approval of such subsidies. Sets forth procedures for the negotiation, acceptance, and payment of such subsidies by the Secretary. Requires replacement propulsion equipment to be of United States origin except under specified circumstances. Classifies such upgraded vessel as "new" or "reconstructed" for specified purposes of such Act. Reduces the age of such vessel by ten years for purposes of the obligation to replace it under any operating- differential subsidy and capital construction fund contract or program.…