(a)A vessel may not be employed in a trade except a trade covered by the endorsement issued for that vessel.
(b)A barge qualified to be employed in the coastwise trade may be employed, without being documented, in that trade on rivers, harbors, lakes (except the Great Lakes), canals, and inland waters.
(c)A vessel with only a recreational endorsement may not be operated other than for pleasure.
(d)A documented vessel, other than a vessel with only a recreational endorsement, or an unmanned barge operating outside of the territorial waters of the United States, may be placed under the command only of a citizen of the United States.