Montreux Convention Regarding The Regime of The Turkish Straits - Terms and Consequences of The Convention

Terms and Consequences of The Convention

The Convention consists of 29 Articles, four annexes and one protocol. Articles 2-7 consider the passage of merchant ships. Articles 8-22 consider the passage of war vessels. The key principle of freedom of passage and navigation is stated in articles 1 and 2. Article 1 provides that "The High Contracting Parties recognise and affirm the principle of freedom of passage and navigation by sea in the Straits". Article 2 states that "In time of peace, merchant vessels shall enjoy complete freedom of passage and navigation in the Straits, by day and by night, under any flag with any kind of cargo."

The International Straits Commission was abolished, authorising the full resumption of Turkish military control over the Straits and the refortification of the Dardanelles. Turkey was authorised to close the Straits to all foreign warships in wartime or when it was threatened by aggression; additionally, it was authorised to refuse transit from merchant ships belonging to countries at war with Turkey. A number of highly specific restrictions were imposed on what type of warships are allowed passage. Non-Black Sea state warships in the Straits must be under 15,000 tons. No more than nine non-Black Sea state warships, with a total aggregate tonnage of no more than 30,000 tons, may pass at any one time, and they are permitted to stay in the Black Sea for no longer than twenty-one days.

Although the treaty is often cited as prohibiting aircraft carriers in the straits, there is no explicit prohibition on aircraft carriers in the treaty. However, the tonnage limits in Article 14, which apply to all non-Black Sea powers, would preclude the transit of modern aircraft carrying ships. In the case of non-Black Sea powers, these terms make it impossible for transit any modern ships carrying aircraft through the straits without violating the terms of the convention.

By contrast, Black Sea powers such as the USSR were able to transit aircraft carrying cruisers through the straits under other terms of the convention. As with non-Black Seas powers, the Montreux convention does not explicitly forbid a Black Sea power from transiting aircraft carriers through the straits, and the tonnage limits in Article 14 also apply to Black Sea powers as well as non-Black Sea powers. However, under Article 11, Black Sea states are permitted to transit capital ships of any tonnage through the straits. Annex II specifically excludes aircraft carriers from the definition of capital ships, but limits the definition of carriers to ships that are designed primarily for carrying and operating aircraft at sea and specifically excludes other ships that merely are able to operate aircraft.

The result of this is that by designing its aircraft carrying ships such as the Kiev and the Admiral Kuznetsov to have roles other than aircraft operation and by designating those ships as "aircraft carrying cruisers" rather than "aircraft carriers" the Soviet Union was able to transit its aircraft carrying ships through the straits in compliance with the convention, while at the same time the Convention denied access to NATO aircraft carriers, which are not covered by the exemption in Article 11.

Under Article 12, Black Sea states are also allowed to send submarines through the Straits, with prior notice, as long as the vessels have been constructed, purchased or sent for repair outside the Black Sea. The less restrictive rules applicable to Black Sea states were agreed as, effectively, a concession to the Soviet Union, the only Black Sea state other than Turkey with any significant number of capital ships or submarines. The passage of civil aircraft between the Mediterranean and Black Seas is permitted, but only along routes authorised by the Turkish government.

The terms of the Convention were largely a reflection of the international situation in the mid-1930s. They largely served Turkish and Soviet interests, enabling Turkey to regain military control of the Straits and assuring Soviet dominance of the Black Sea. Although the Convention restricted the Soviets' ability to send naval forces into the Mediterranean sea - thereby satisfying British concerns about Soviet intrusion into what was considered a British sphere of influence - it also ensured that outside powers could not exploit the Straits to threaten the Soviet Union. This was to have significant repercussions during World War II when the Montreux regime prevented the Axis powers from sending naval forces through the Straits to attack the Soviet Union. The Axis powers were thus severely limited in naval capability in their Black Sea campaigns, relying principally on small vessels that had been transported overland by rail and canal networks. Auxiliary vessels and armed merchant ships occupied a grey area, however, and the transit of such vessels through the straits led to friction between the Allies and Turkey. Repeated protests from Moscow and London led to the Turkish government banning the movements of "suspicious" Axis ships with effect from June 1944 after a number of German auxiliary ships were permitted to transit the Straits.