(a) Every seaman employed on any merchant vessel of the United States of 100 gross tons or upward, except vessels employed exclusively in trade on the navigable rivers of the United States, must carry a valid merchant mariner credential (MMC) or merchant mariner's document (MMD) with all appropriate endorsements for the position served and, beginning on April 15, 2009, a valid Transportation Worker Identification Credential (TWIC). Provisions of this section are not applicable to unrigged vessels except seagoing barges and certain tank barges.
(b) Every seaman, as referred to in paragraph (a) of this section, shall produce a valid MMC or MMD with all applicable rating endorsements for the position sought and, beginning on April 15, 2009, a valid TWIC to the master of the vessel at the time of his or her employment before signing articles of agreement. Seamen who do not possess one of these credentials may be employed at a foreign port or place.
(1) Every person employed on any merchant vessel of the United States of 100 gross tons and upward, except those navigating rivers exclusively and the smaller inland lakes, below the grades of officer and staff officer, must possess a valid MMC or MMD with all appropriate endorsements for the positions served;
(2) No endorsements are required of any person below the rank of officer employed on any unrigged vessel except seagoing barges and certain tank barges.
(3) No endorsements are required of any person below the rank of officer employed on any sail vessel of less than 500 net tons while not carrying passengers for hire and while not operating outside the line dividing inland waters from the high seas, as defined in section 2 of the act of February 19, 1895, as amended (33 U.S.C. 151) and in 33 CFR part 82.
(d) Each person serving as an able seaman or a rating forming part of a navigational watch on a seagoing ship of 500 gross tonnage (200 GRT) or more shall hold an STCW endorsement certifying him or her as qualified to perform the navigational function at the support level, in accordance with STCW (incorporated by reference, see § 12.01-3).
(e) Each person serving as a qualified member of the engine department (QMED) or a rating forming part of a watch in a manned engine-room or designated to perform duties in a periodically unmanned engine-room, on a seagoing ship driven by main propulsion machinery of 750 kW [1,000 hp] of propulsion power or more, shall hold an STCW endorsement certifying him or her as qualified to perform the marine-engineering function at the support level, in accordance with STCW.
(f) Notwithstanding any other rule in this part, no person subject to this part serving on any of the following vessels needs to hold an STCW endorsement, either because he or she is exempt from application of the STCW, or because the vessels are not subject to further obligation under STCW, on account of their special operating conditions as small vessels engaged in domestic voyages:
(1) Small passenger vessels subject to subchapter T or K of title 46, CFR.
(2) Vessels of less than 200 GRT (other than passenger vessels subject to subchapter H of title 46, CFR).