Transatlantic cables incident. In 1959, the Soviet vessel MV Novorossiysk was boarded by personnel from the United States warship  during the transatlantic cables incident. The action was in response to a complaint filed by AT&T and Western Union over breakages in their undersea telecommunications cables. It was the first and, until 2024, only enforcement action taken under the Convention for the Protection of Submarine Telegraph Cables of 1884. 

Accidental damage to undersea cables by fishing vessels was a common occurrence at the time and a U.S. Navy investigation concluded that Novorossiysk may have unintentionally cut the cables. The Soviet Union denounced the U.S. boarding action as "provocative".

Background
Undersea telecommunications cables have been the object of sabotage since the Spanish–American War. During the Cold War, the Soviet Union outfitted a number of ships in its fishing and merchant fleets with intelligence-gathering and marine sabotage equipment. This operational provisioning of Soviet merchantmen was known to the United States Navy and, for its part, the United States interfered with the Soviet Union's own undersea cables. 

According to the International Cable Protection Committee, it is common for fishing vessels to unintentionally break undersea cables. An AT&T technician, interviewed in 1959 by the Associated Press, said the company's undersea cables were at the time being regularly cut by accident each summer by Portuguese and Norwegian fishing vessels trawling for cod in the North Atlantic.

Convention for the Protection of Submarine Telegraph Cables
The 1884 Convention for the Protection of Submarine Telegraph Cables was the first international compact to deal with underwater cables. It proscribes breakage or damage of such cables — except by belligerents engaged in open war — and permits the naval forces of state parties to engage in certain enforcement actions against suspected offenders. 

Article 10 of the convention provides that:

The incident
Between February 21 and February 25, 1959, several undersea telecommunications cables in the North Atlantic suffered a total of 12 breaks, of which nine were "tension breaks" and three were "man-made cuts severing the cables". The cables were owned by AT&T and Western Union, who reported the breaks to the U.S. Government. AT&T also sent a surveillance aircraft to the area, which sighted the Soviet fishing trawler MV Novorossiysk. The AT&T aircraft air dropped a note to the deck of the Novorossiysk demanding she stop trawling pending investigation. 

In response to the report from AT&T and Western Union, the United States Navy dispatched USS Roy O. Hale to the area. On February 26, 1959, Roy O. Hale came in flaghoist range of Novorossiysk in international waters approximately  from the coast of Newfoundland. Taking note that the Soviet ship was the only vessel in the immediate vicinity of the cable breaks, Roy O. Hale raised signal flags indicating "heave to, we are sending a boat". The boarding of the Soviet vessel was ordered by U.S. Navy Admiral William Martin, who was not aboard Roy O. Hale at the time of the action. 

Novorossiysk complied with the instruction and a five-man, unarmed party commanded by Roy O. Hales executive officer Donald M. Sheely boarded the Soviet ship. The American and Soviet mariners communicated with each other in French. According to the U.S. Government, after collecting evidence for about one hour, the boarding party returned to its vessel and Novorossiysk departed the area.

United States account of investigation
According to the United States Government, in a note verbale addressed to the Soviet foreign ministry after the incident, the U.S. Navy boarding party inspected Novorossiysks log books and catch. It noted that the ship had recently caught bottomfish, which might be consistent with the dragging of fishing nets across the ocean floor and that the man-made cutting of the cables could be explained by deck crew severing them to disentangle the cables from their nets before discarding them back into the ocean. 

The United States noted the captain of Novorossiysk was "friendly and cooperative" and concluded that any breakage of the cables was probably unintentional.

Soviet response
The Soviet Union denounced the U.S. action against Novorossiysk, describing it as "provocative".

Historical context
The transatlantic cables incident was the first enforcement action taken under the Submarine Cables Convention. On about November 20, 2024, in what was cited as the second enforcement action under the convention, a Royal Danish Navy warship detained the Chinese merchant vessel Yi Peng 3 while investigating the damaging of two undersea fiber optic cables in the Baltic Sea.

Notes

References

External links
 LIFE Magazine photo of the U.S. Navy boarding party debriefing

Cold War
Soviet Union–United States relations