Admiralty or Maritime Law is a body of law governing navigation and
shipping. Admiralty law is under the specific domain of federal law,
created through Article III of the Constitution. Maritime Law governs
not only U.S. tidal waters, but any waters within the United States
used for navigation. Because Maritime Law is governed exclusively by
the federal branch, states have no jurisdiction to legislate or govern
maritime matters.
Under Admiralty law, a ship's flag determines what country has
jurisdiction. Thus, an American ship flying an American flag off the
coast of Africa, is still governed by American maritime law;
similarly, a Russian ship on the coast of California would be governed
by Russian maritime law. Nevertheless, an American court could still
exercise jurisdiction over the Russian ship - the court could decide
whether to apply Russian maritime law or refuse to exercise
jurisdiction.
In general international maritime law is consistent among all
countries.
http://www.qs138.com/admiralty-law/a...w-overview.htm