The unimpeded use of the Straits connecting the Black Sea and the Mediterranean Sea has historically been one of the key factors for the stable economic development of the Black Sea states, the expansion of their cooperation with other countries and the protection of their national interests. In the context of the difficult situation in the Ukraine and the Middle East, the issue of regulating navigation on the Black Sea is becoming particularly relevant.
The Convention on the conditions of passage of the Black Sea Straits was concluded on July 20, 1936 in Montreux (Switzerland) during the conference on the revision of the first similar document, adopted in 1923 in the city of Lausanne (Switzerland). The new agreement entered into force on November 9, 1936.
Formally, its validity period was 20 years. However, in accordance with the provisions of the document, it “remains in force beyond the specified period until two years have elapsed after the notification of denunciation has been sent to the government of France” (the Depositary), which is obliged to inform all other participants.
As of August 2019, the following states have joined the agreement: Australia, Bulgaria, Great Britain, Cyprus, France, Greece, Italy, Japan, Russia, Romania, Turkey and the Ukraine.
The Montreux Convention cemented Turkey’s sovereignty over the Bosphorus and the Dardanelles Straits. It stipulates that commercial vessels of all states in times of peace and war (when Turkey is a non-belligerent party) enjoy full freedom of passage and navigation in the Black Sea Straits day and night, regardless of the flag of the state and the cargo being transported, without any formalities. At the same time, Ankara has the right to charge a fee from each vessel to cover the costs of sanitary control, navigation support and maintenance of the rescue service.
The order and conditions of transit through these Straits of ships with respect to the Black Sea and non-Black Sea states differ. It follows from the document that the former in peacetime can sail ships of any class. It is forbidden to perform deck aviation flights only during this period.
The Black Sea countries also have the right to sail their submarines, built or purchased outside this sea through the Straits if they are en route to their home base, provided that Turkey is notified in advance of the laying or purchase of such ships. In addition, submarines belonging to these states can pass through the Straits for repairs at shipyards located outside this sea, provided that accurate information on this fact will be provided to the Turkish side. In both cases, the boats must pass in the daytime, on the surface and in single file.
Non-Black Sea countries are allowed to sail only light surface ships, small combat and auxiliary vessels on the Black Sea. The total maximum tonnage of all foreign military vessels in transit through the Straits should not exceed 15 thousand tonnes. Their passage is possible only in the daytime, and at the same time the number does not exceed nine units. The total tonnage of warships and vessels of these states simultaneously located in the Black Sea should not exceed 45 thousand tonnes, and any one non-Black Sea country, 30 thousand tonnes. However, regardless of the purpose of their stay, they cannot stay there more than 21 days.
It should be noted that the article on the total displacement of ships of non-Black Sea states, simultaneously located in the Black Sea, allows for its double interpretation. Thus, Ankara and its NATO allies assume that when in the first half of the 1980s the total tonnage of the Soviet Black Sea Fleet exceeded “by at least 10 thousand tonnes the tonnage of the strongest fleet” at the time of signing the Convention, paragraph (b) of this article came into force.
In this regard, the total tonnage of 30 thousand tonnes, provided for in paragraph (a) for non-Black Sea states, was increased to a maximum value of 45 thousand tonnes, and one ship to 20-30 thousand tonnes. According to the Turkish interpretation, this action is irreversible. However, the requirements of the same article can be interpreted in a different way: the tonnage of ships of these states should be calculated “at any given moment” in proportion to the current total displacement of the fleets of the Black Sea countries. This allows you to reduce the above limits to 30 thousand and 20 thousand tonnes, respectively. This is the view of the Russian Federation.
In order for warships to pass through the Straits, the Turkish government must be notified in advance via diplomatic channels 8 days prior, and non-Black Sea states must notify 15 days in advance. Thus, destination, name, type and number of ships, as well as the date of passage in the original direction and return date must be specified.
Any change of terms is subject to additional notification at least three days in advance.
If Turkey participates in a war, the passage of warships through the Straits “will depend solely on the discretion of the Turkish government” (Article 20). If there is a “threat of immediate danger” for Turkey (Article 21), similar measures may be taken. However, they can be cancelled if two thirds of UN Security Council votes recognise them as unfounded.
During a war in which Turkey is not involved, the Straits must be closed to the passage of military vessels of the belligerent state. Warships that have passed through the Straits and found themselves outside their main port of anchorage can return to them. However, Turkey may deny the right of the ships of the state that caused the said situation.
During a war when Turkey is a combatant, merchant ships that do not belong to a country at war with it will enjoy the right of free passage and navigation in the Straits, provided that they do not assist the enemy. These vessels in each case will have to pass through the Straits in the daytime along the route indicated by the Turkish authorities.
In cases where Ankara considers itself to be in immediate military danger, free passage for merchant ships is maintained, but they can cross the Straits as in times of war.
The Black Sea countries are required to report to Turkey the total displacement of their fleet’s ships annually on January 1 and July 1.
The military and political leadership of the republic considers maintaining control over the Black Sea Straits of the Bosphorus and the Dardanelles as one of the most important elements of maintaining the status of a regional power with a strategically important geographical position in the European-Asian continental region. Ankara’s monopoly right to regulate navigation in the Straits is a tool for exerting some pressure on the Black Sea states, limiting the transit of warships and civilian vessels at its discretion.
In this case, the restriction (difficulty) of their passage, as well as the introduction of a complete ban can be implemented both within the framework of international law and bypassing it.
Thus, against the background of the aggravation of relations with the Russian Federation in 2015 and 2016, Russian civilian vessels were delayed in Turkish ports and straits under the pretext of various formal violations related to the operation of ship equipment and security systems.
In addition, Turkey periodically restricts the right to free passage of ships, explaining this by measures to normalise the environmental situation in the straits area. In February 2019, for example, there was a significant increase in the time it took for oil tankers to get permission to pass the Black Sea Straits from the port of Novorossiysk to Europe and back. According to official data from Ankara, the reasons for the delay were adverse weather conditions.
One of the ways to change the situation around the legal status of the Montreux Convention may be the implementation by the Turkish side of the transport project called the “Istanbul Canal”. In accordance with it, it is planned to build an artificial shipping channel to the west of Istanbul. It is assumed that its length will be 45-50 km, width of 400 m at the base and 500 m on the surface, with a depth of 25-35 m.
By December 2015, Turkish experts had done feasibility studies for the project, and in April 2016, the Turkish Parliament passed a law on the allocation of land for the construction of the canal.
However, there is a question about the international legal status of such a project, including in the context of the current agreement. According to the Turkish side, the Istanbul Canal is primarily an economic project aimed at reducing the transit load on the Bosphorus Strait and improving the safety of commercial shipping.
As for the international legal aspect, the regime of the Montreux Convention, covering the area from the Mediterranean to the Black Sea, will remain unchanged, including the new artificial sea route.
The conditions of passage through the Strait zone established by this document will continue to apply to warships. However, it is possible that in the event of any emergency situations in the Bosphorus Strait (adverse climatic conditions, man-made disasters, etc.), the Turkish side, temporarily closing it for the passage of ships, will send military ships through the cannel under construction. According to Ankara, such decisions will be made in compliance with all the requirements of the Montreux Convention.
Since 2014, due to the political crisis in the Ukraine and the deterioration of Russian-American relations, the United States and its NATO allies have sought to strengthen their military presence in the Black Sea zone: for example, the number of calls by warships of the Alliance countries (the vast majority of them belong to the American Navy) to the Black Sea has increased significantly. As the same time, it increased the number of exercises involving the Black Sea countries, members of NATO, the Ukraine, Georgia, which works on forming operational formations and groups of multi-national navy compositions and for various purposes, as well as their deployment in areas of assignment.
In the context of continuing to expand its military activities, the Alliance is exploring the possibility of revising certain provisions of the Montreux Convention, in particular removing restrictions on the displacement of military vessels passing through the Bosphorus and the Dardanelles, as well as extending their stay. This would make it possible to increase the speed of deployment of NATO naval forces on the south-eastern flank of the bloc and ensure the build-up of the naval group in the Black Sea.
However, according to the Montreux Convention, the initiative to change one or more of its provisions can only come from the signatory states. The decision on the appropriate revision should be taken in most cases unanimously by convening a special conference, if necessary (once every five years, the nearest one would be by the end of 2021).
Some amendments concerning the total tonnage of warships and vessels of non-Black Sea states that are simultaneously in transit through the Straits (Article 14) or directly in the Black Sea (Article 18) can be adopted with the consent of “¾ of the contracting parties”, comprising of ¾ of the Black Sea states, among them Turkey.