International Voyage Load Line Act of 1973

International Voyage Load Line Act - Directs the Secretary of the Department in which the Coast Guard is operating to prescribe loadlines, the marking therof and associated condition surveys for vessels engaged in international voyages. Provides that the Secretary shall indicate the minimum freebord to which each vessel may be loaded, giving due consideration to, and making differentials for, the service, type, and character of each vessel.

Permits the Secretary, with the consent of the Secretary of the Treasury, to utilize officers of the bureau of Customs to enforce this Act. Authorizes the Secretary to issue a loadline certificate upon completion of survey requirements and a finding that the loadline is positioned and marked in the manner prescribed. Authorizes the appointment of surveyors and the revocation of such appointment by the Secretary.

Provides for the issuance of a certificate of exemption to a vessel, which is so entitled by virtue of an international agreement to which the United States is signatory. Provides for the recognition of loadlines required by foreign countries, when they are equally effective.

Prohibits any vessel from being loaded so as to submerge the prescribed loadline. Authorizes the Secretary to detain any vessel which violates the provisions of this Act. Imposes various civil and criminal penalties for violations of this Act.