According to the United Nations Convention on the Law of the Sea, no matter whether a country is near the sea or not, it has the right to register ships of its nationality. When a ship sails on the high seas, it must fly the flag of its registered country.
In actual operation, as long as the ship flies the flag of a certain country, the ship is regarded as having the nationality of that country, and that country is the flag country of the ship. When sailing on the high seas, ships only abide by international law and the laws of the flag state.
However, in order to obtain a large number of ship registration fees, some countries have lower requirements on ship structure, seaworthiness, working conditions and crew training, and relax the nationality requirements for ship registration to attract ship registration.
This is also why Marshall Islands, Bahamas, Cyprus and other countries are always far ahead in the world when doing ship registration statistics.
Although most countries prohibit ships from acquiring multiple nationalities in law and doctrine, the current international law also tries its best to prohibit ships from possessing multiple nationalities. But in practice, there will always be some ships with multiple nationalities.
For these ships with multiple nationalities, countries usually adopt the following legal propositions when managing ships:
(1) meaning of the shipowner. The statement said that the nationality of the ship depends on the wishes of all parties. The disadvantage is that the shipowner can change the nationality of the ship at will.
(2) Flag method theory. This statement claims that the nationality of a ship is determined by the national flag it flies, and the laws of that country shall be applied to govern the ship. But this statement is easy to confuse the nationality and flag of the ship, which is essentially similar to the meaning of the owner.
(3) the analogy of the nationality of natural persons. This statement advocates that the solution applicable to the nationality conflict of natural persons should be compared with the nationality conflict of ships. That is, when there is a nationality conflict between ships, the nationality of domestic ships takes precedence; When there is a nationality conflict between foreign ships, the nationality of the ships shall be determined according to the principle of closest connection.