Spy ships I

Spy ships in the modern sense have been used at least since the early Cold War, and are in use by all major powers. Their uses, in addition to listening in on communications and spy on enemy fleet movements, were to monitor nuclear tests and missile launches (especially of potential ICBMs).

One of the most important functions for both Cold War spy ship fleets, especially in the 1960s, was the gathering of submarine 'signatures' - the patterns of noise that could often identify the specific type of submarine and were thus valuable in anti-submarine warfare. During that era, the USA fielded about 80 vessels, usually classified as 'environmental research' craft, while the Soviets had around 60 ships, often converted trawlers or hydrographic research ships.

Spy ships II

Conserver, Narragansett, Alpinist, Moma.  Sea of Japan.  A Soviet Alpinist class intelligence ship and a Soviet Moma class intelligence collection ship shadow the fleet tug USNS Narragansett (T-ATF-167) and the USS Conserver (ARS-39) during salvage operations for downed Korean Air Lines Flight 007.  Official U.S. Navy photo by PH2 Paul Soutar

Soviet intelligence trawlers shadowing US Navy vessels involved in the search for KAL 007 in 1983.

The Russian Intelligence Trawler AGI Vertikal. Photographed by PH1 Fred Martin from USNS Duttton, 1965

In the late 1980s, the Soviet fisheries fleet was known for having equipped many of their thousands of ships with sophisticated SIGINT and ELINT equipment, thus functioning as auxiliary spy ships tracking western naval vessels and electronic communications (though their main function remained commercial fishing).

Modern Russian/Soviet Phishing Fleet Boats

Spy ships III

The Soviet Union. Due to their relative lack of electronic listening posts overseas—in comparison to the Americans, who possessed signals intelligence (SIGINT) facilities throughout the world—the Soviets initially took the lead in the use of ships to gather intelligence. From the 1950s, they began using what came to be their preferred intelligence-gathering craft, a fishing trawler. The design of the trawler, which was made to store many days' catch in insulated compartments, made it ideal for extensive activities below deck.

As the Cold War continued, the Soviets expanded and improved their intelligence-collection ships, known to U.S. intelligence as AGIs, the AG being code for "miscellaneous auxiliary" and the I a designator of enemy craft. Later models were designed and built specifically to serve as collection platforms. Eventually they became large enough to include on-board intelligence processing facilities, greatly improving the speed with which raw data became usable intelligence for Soviet operatives.

During the Vietnam War, a pair of Soviet AGIs, one near Guam and the other in Vietnam's Gulf of Tonkin, kept a close watch on U.S. forces, and in some cases may have provided Hanoi with advance notice of U.S. airstrikes. Near the end of the Cold War, the Soviets had a fleet of about five dozen AGIs dispatched throughout the globe. A particular area of interest lay just to the east of Florida, in international waters and close to friendly ports in Cuba, from which Soviet AGIs could monitor activities at U.S. naval bases in South Carolina, Georgia, and Florida.