.
Montreux Convention (1936) ..
Flag of convenience (FOC) is a business practice whereby a ship's owners 
register a 
merchant ship in a ship register of a country other than that of the ship's owners, and the ship flies the 
civil ensign of that country, called the 
flag state. The term is often used pejoratively, and although common, the practice is sometimes regarded as contentious. Each merchant ship is required by 
international law to be registered in a registry created by a country, and a ship is subject to the laws of that country, which are used also if the ship is involved in a case under 
admiralty law. A ship's owners may elect to register a ship in a foreign country which enables it to avoid the regulations of the owners' country which may, for example, have stricter safety standards. They may also select a jurisdiction to reduce operating costs, avoiding higher taxes in the owners' country and bypassing laws that protect the wages and working conditions of 
mariners. The term "flag of convenience" has been used since the 1950s. A registry which does not have a 
nationality or 
residency requirement for ship registration is often described as an open registry. Panama, for example, offers the advantages of easier registration (often online) and the ability to employ cheaper foreign labour. Furthermore, the foreign owners pay no income taxes.
The modern practice of ships being registered in a foreign country began in the 
1920s in the 
United States when shipowners seeking to serve alcohol to passengers during 
Prohibition registered their ships in Panama. Owners soon began to perceive advantages in terms of avoiding increased regulations and rising labor costs and continued to register their ships in 
Panama even after Prohibition ended. The use of open registries steadily increased, and in 1968, 
Liberia grew to surpass the 
United Kingdom with the world's largest ship register. As of 2009, 
more than half of the world's merchant ships were registered with open registries, and almost 40% of the entire world fleet, in terms of 
deadweight tonnage, were registered in 
Panama, Liberia, and the Marshall Islands. In 2006, up to 20% of high-seas fishing vessels were registered in states they were not connected to. According to 
IHS Markit, in March 2017, Panama had 8,052 ships on its registry, 
Singapore had 3,574 ships, Liberia had 3,277 ships, the Marshall Islands had 3,244 ships and 
Hong Kong had 2,594 ships.
Open registries have been criticised, mainly by 
trade union organisations based in developed countries, especially those in the European Union, United States, Japan, Canada, or the United Kingdom. One criticism is that shipowners who want to hide their ownership may select a flag-of-convenience jurisdiction which enables them to be legally anonymous. Some ships with flags of convenience have been found engaging in crime, offering substandard working conditions, and negatively impacting the environment, primarily through 
illegal, unreported and unregulated fishing. Prior to the implentation of the 
International Convention on Tonnage Measurement of Ships, 1969, shipowners may have selected a jurisdiction with measurement rules that reduced the certified 
gross register tonnage of a ship, to reduce subsequent port of call dock dues. Such was a consideration when 
Carnival Cruise Line changed the flag of the RMS 
Empress of Canada in 1972 to that of Panama.[
citation needed] In 2011, 
Cunard Line registered all its ships in 
Bermuda, which, besides other considerations, enabled its ship captains to marry couples at sea. Weddings at sea are described as a lucrative market.
As of 2009, thirteen flag states have been found by 
international shipping organisations to have substandard regulations. On the other hand, maritime industry practitioners and seafarers from other countries contend that this is a natural product of globalisation. Supporters of the practice, however, point to economic and regulatory advantages, and increased freedom in choosing employees from an international labour pool. Ship owners from developed countries use the practice to be competitive in a global environment. As of 2009, ships of thirteen flags of convenience have been targeted for special enforcement by countries when they visit ports in those countries, called 
port state control.
The 
United Nations Convention on the Law of the Sea (
UNCLOS), also called the 
Law of the Sea Convention or 
the Law of the Sea treaty, is an international agreement that resulted from the third United Nations Conference on the Law of the Sea (UNCLOS III), which took place 
between 1973 and 1982. The Law of the Sea Convention defines the rights and responsibilities of nations with respect to their use of the world's oceans, establishing guidelines for businesses, the environment, and the management of marine 
natural resources. The Convention, concluded in 
1982, replaced the 
quad-treaty 1958 Convention on the High Seas. UNCLOS came into force in 
1994, a year after 
Guyana became the 
60th nation to ratify the treaty. As of 
June 2016, 167 countries and the 
European Union have joined in the Convention. It is 
uncertain as to what extent the Convention 
codifies customary international law.
UNCLOS replaces the 
older 'freedom of the seas' concept, dating from the 
17th century. According to this concept, national rights were limited to a specified belt of water extending from a nation's 
coastlines, usually 
3 nautical miles (5.6 km; 3.5 mi) (
three-mile limit), according to the '
cannon shot' rule developed by the Dutch jurist 
Cornelius van Bynkershoek. All waters beyond national boundaries were considered 
international waters: free to all nations, but belonging to none of them (the 
mare liberum principle promulgated by 
Hugo Grotius).
In the 
early 20th century, some nations expressed their desire to extend national claims: to include 
mineral resources, to 
protect fish stocks, and to provide the means to 
enforce pollution controls. (The 
League of Nations called a 
1930 conference at 
The Hague, but no agreements resulted.) Using the customary international law principle of a nation's right to protect its natural resources, President 
Harry S. Truman in 
1945 extended United States control to all the natural resources of its 
continental shelf. Other nations were quick to follow suit. Between 
1946 and 1950, 
Chile, Peru, and Ecuador extended their rights to a distance of 
200 nautical miles (370 km; 230 mi) to cover their 
Humboldt Current fishing grounds. Other nations extended their territorial seas to 
12 nautical miles (22 km; 14 mi).
[7]By 
1967, 
only 25 nations still used the 
old three nautical mile limit, while 
66 nations had set a 
12-nautical-mile (22 km) territorial limit and 
eight had set a 
200-nautical-mile (370 km) limit. As of 
28 May 2008, only 
two countries (Jordan and Palau) still use the 
3-mile (4.8 km) limit. That limit is also used in certain 
Australian islands, an area of 
Belize, some 
Japanese straits, certain areas of 
Papua New Guinea, and a few 
British Overseas Territories, such as 
Gibraltar.
. It guarantees 
. In 
, military vessels are limited in number, tonnage and weaponry, with specific provisions governing their mode of entry and duration of stay. If they want to pass through the Strait, 
 to the Turkish authorities, which, in turn, must inform the parties to the convention. In 
 about the passage of warships as it sees fit. The 
 to the Convention.
While it was designed for a particular geopolitical context, and remains unchanged since its adoption, the Montreux Convention has endured as a "solid example of a 
", since most of its terms are still followed.