There is a branch of law that governs navigations and shipping. And this is Admiralty or Maritime Law that is under the special domain of federal law, created through Article III of the Constitution. Its designation is to govern not only U.S. tidal waters, but any waters within the United States used for navigation. States have no jurisdiction to legislate or govern maritime matters. This is because Admiralty Law is governed by the federal branch.
As a ship's flag determines what country has jurisdiction, in this way, an American ship, flying an American flag off the coast of Africa, is still governed by American maritime law. Likewise, a ship of another country on the coast of California would be governed by its maritime law.
Eleanor of Aquitaine introduced Admiralty law in England. She was acting as regent for her son, King Richard the Lionheart. Moreover, she had earlier established admiralty law on the island of Oleron where it was published as the Rolls of Oleron in her own lands. She had learned about it in the eastern Mediterranean while on Crusade with her first husband, King Louis VII of France. All admiralty cases are handled by special admiralty courts in England.
So, maritime is under the jurisdiction of the United States district courts and appeal from judgments in admiralty case lies to the United States courts of appeals. Nevertheless, state courts have concurrent jurisdiction in admiralty when state law claims are at issue. This is because admiralty courts in the United States are courts of limited jurisdiction.
It is possible for state courts to have jurisdiction in admiralty when the matters being adjudicated are local. The Supreme Court is the court of last resort for all cases arising under admiralty law. This is according to Article III of the United States Constitution.
However, Admiralty Courts assume jurisdiction by virtue of the presence of the ship in its territorial jurisdiction irrespective of whether the ship is national or not. It also doesn't matter whether it is registered or not and wherever the residence or domicile or their owners may be. The court to retain jurisdiction can arrest a vessel. But it is possible to protect state owned vessels from arrest. And they usually are.
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