A person employed as an officer or member of a crew on a ship who otherwise has dual
coverage under the social security taxation and coverage laws of both countries will
only have coverage under the laws of the country whose flag the ship flies.
A ship is considered to fly the flag of the United States if it is an American vessel
as defined in section 210(c) of the Act. Under that definition, an American vessel
is one that is documented or numbered under U.S. law or one that is not documented
or numbered under the law of any country, if its crew is employed solely by one or
more U.S. citizens or residents, or corporations organized under Federal or State
law.