Under Article 10, a person employed on a U.S. or Swiss ship who is covered under the laws of both the United States and Switzerland will be covered only under the laws of the country whose flag the ship flies.  Article 10 provides that a ship flies 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 laws 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.