DESOTO patrol

DESOTO patrols (DeHaven Special Operations off TsingtaO)^[1] were patrols conducted by U.S. Navy destroyers equipped with a mobile "van" of signals-intelligence equipment used for intelligence collection in hostile waters.^[2] The USS De Haven became the namesake for these patrols.^[3] De Haven performed the first patrol off the coast of China in April 1962. The USS Agerholm carried out the first patrol to target North Vietnam in the Gulf of Tonkin in December 1962.^[3]

These patrols were initially a response to the Chinese Communists' unexpected re-definition^[when?] of their territorial waters to include all waters shoreward from lines drawn tangentially to, and between, twelve-mile circles drawn around their offshore islands. Such a declaration represented a huge expansion of their claims. This inhibited the lawful navigation of international waters as defined by US interests and increased the likelihood and frequency of formal diplomatic "serious warnings" issued by Beijing when any Seventh Fleet units navigated through these areas. This became a situation to which Commander Seventh Fleet felt compelled to respond.^[1]

These types of patrols had previously been conducted off the coasts of the Soviet Union, China, and North Korea, but are perhaps of greatest significance for their role in the Vietnam War.^[1] There were three components to the purpose of these patrols. First, they would establish and maintain the presence of the U.S. Seventh Fleet in the international waters off the China coast and later the Vietnamese coast. Second, they would serve as a minor Cold War irritant to the Chinese Communists. Third, they would collect as much intelligence as possible during the patrols.^[3]

Tactically, the patrols off Vietnam aimed to intercept North Vietnamese Army intelligence and to relay it to South Vietnamese Army forces. With the intercepted communications, the South Vietnamese were able to more effectively coordinate their raids. The aircraft carrier USS Ticonderoga provided destroyers taking part in the DESOTO patrols off Vietnam with air support.^[1]

The DESOTO patrols off Vietnam from 1963 onwards formed part of a larger scheme known as Operation 34A. Run by the Department of Defense at the time, Operation 34A, or "OPLAN 34Alpha" was a top-secret program consisting primarily of covert actions against the North Vietnamese.^{[citation needed]}