Wherever no treaties regulate the proportions, a simple right applies: the right of the strongest.That is the basis for a lot of misery because those in conflict are the strongest, that in a subsequent or follow-up conflict does not have to be, if only because the other may have allies on his side who have the same interests and which are jointly stronger. This reality is the basis of international law, enshrined in treaties. That reality also explains why the US often do not commit to these treaties and-as under those Trump-even denounce treaties.
In the context of the law of the sea, this picture from Wikipedia is interesting:
Dark green: Ratified
Light green: Signed, but not yet ratified
Grey: Countries that have no advantage in agreeing to the agreements of the UN Convention on the Law of the Sea.
Special position and importance of the Netherlands
First of all a piece of patriotic history, because for the Netherlands was as a trading nation and there is much to be gained in establishing international treaties guaranteeing the free right to use the sea.
In Wikipedia you will find this with Hugo de Groot who is seen as the groundkeeper of the sea-real:
In 1603, a Portuguese ship, the Santa Catarina, was staged at the Straits of Malacca and seized by Admiral Jacob van Heemskerk.
This action was controversial even in the Netherlands, but the huge booty proved worth millions and made more desire. The Vereenigde Oostindische Compagnie, founded in 1602, therefore made a request to Hugo de Groot to write a treatise with which the confiscation could be justified. Hugo de Groot stated in this treatise, Mare Liberum, that the Portuguese did not have the exclusive right to the lucrative spice trade with India, but that the Dutch were also allowed to trade with India. De Groot argued that the sea and the air were free because they could not be occupied by any country and therefore could not be owned by a country. He also stated that it was a general good to keep the seas free for all; It was a disadvantage for all countries if the seas were owned by certain countries.
Mare Liberum was also intended to strengthen the negotiating position with Spain.The Republic of the seven United Netherlands was in negotiations with Spain about the twelve-year-old file during the Eighty Years ‘ War. Spain and Portugal demanded the exclusive right to trade in the West and East Indies. The marketing of Hugo de Groot was intended to refute these claims, which also succeeded, because the Netherlands received the right to trade with the Indies with the twelve-year-old file.
The reality at sea
Despite the fact that the United States of America does not have a message to the international agreements in the UN Maritime Convention, it considers itself largely bound by customary law, so that at sea it is not entirely the right of the strongest to be the case.
The United Nations has a nice mess of rules when it comes to rules on open water.You’ll find them in the United Nations Convention on the Law of the Sea.
But ships fall under the law of the country of origin at all times.
A ship on the open sea is governed by the laws of his country of origin.
Of course you can not do anything on the open sea.Whether you get away with it is another matter.