33 C.F.R. § 141.5
Applicability
(a) This subpart applies to employment of personnel on units engaged in OCS activities, except as provided in paragraph (b) of this section.
(b) This subpart does not apply to employment of personnel on any:
(1) Vessel subject to the citizenship requirements of 46 U.S.C. 8103 for pilots, crew, and officers holding a valid license or MMC with officer endorsement when the vessel is transiting to or from an OCS facility or a United States port;
(2) Vessel subject to the citizenship requirements of 46 U.S.C. 7102 and 8103 for officers and crew on federally subsidized or documented vessels; or
(3) Unit over 50 percent of which is owned by one or more citizens of a foreign nation or with respect to which one or more citizens of a foreign nation have the right effectively to control, except to the extent and to the degree that the President determines that the government of such foreign nation or any of its political subdivisions has implemented, by statute, regulation, policy, or practice, a national manning requirement for equipment engaged in the exploration, development, or production of oil or gas in its offshore areas.
(c) The Commandant may, upon request or upon that person's own initiative, determine whether over 50 percent of a particular unit is owned by citizens of a foreign nation or whether citizens of a foreign nation have the right effectively to control the unit.
(d) In determining whether ownership or a right effectively to control exists, the Commandant may consider operational control of a unit, management responsibility, title, lease and charter arrangements, and financial interests.
(e) The owner or operator of any unit affected is notified of the Commandant's determination.