The ''Guardian''-class radar picket ships were a class of ocean

radar picket A radar picket is a radar-equipped station, ship, submarine, aircraft, or vehicle used to increase the radar detection range around a nation or military (including naval) force to protect it from surprise attack, typically air attack, or from cr ...

ships (YAGR, later AGR), converted 1954–1958 from

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

Liberty ship Liberty ships were a ship class, class of cargo ship built in the United States during World War II under the Emergency Shipbuilding Program. Though British in concept, the design was adopted by the United States for its simple, low-cost constr ...

s acquired by the U.S. Navy. Their task was to act as part of the radar defenses of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

in the Cold War, serving until 1965.

Ship type

The converted Liberty ships were typically the boxed aircraft transport version, type Z-EC2-S-C5. The

hull classification symbol The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol (sometimes called hull code or hull number) to identify their ships by type and by ...

of the ships was initially YAGR, changed to AGR in 1958: originally the District Auxiliary, Miscellaneous (YAG) classification with hull numbers YAG-41 through YAG-44 for the first four ships was considered, but this symbol was not adopted.YAG
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Equipment

As converted, each ship carried an

AN/SPS-8 AN/SPS-8 is a two-dimensional radar manufactured by General Electric. It was used by the United States Navy, US Navy as a Height-finding radar, height finding radar after World War II, and was equipped aboard naval ships during the Cold War. Varia ...

height finding radar,

AN/SPS-12 AN/SPS-6 is a two-dimensional radar manufactured by Bendix and Westinghouse Electric. It was used by the US Navy as a first-generation air-search radar after World War II, and was widely exported to allies. In addition, the improved AN/SPS-12 is ...

air/surface search radar, AN/SPS-17 long range air search radar, and AN/UPA-22

IFF In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false. The connective is bicondi ...

sensor. The AN/SPS-8 was later replaced on some ships by the AN/SPS-30. The AN/SPS-17, purpose built for the ''Guardian'' class, could detect large aircraft such as

bomber A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching aerial torpedo, torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped ...

s up to away and small aircraft up to away.

Service

The AGRs were based on both coasts at

Newport, Rhode Island Newport is an American seaside city on Aquidneck Island in Newport County, Rhode Island. It is located in Narragansett Bay, approximately southeast of Providence, south of Fall River, Massachusetts, south of Boston, and northeast of New ...

(later Davisville, Rhode Island) and

Treasure Island, California Treasure Island is an artificial island in the San Francisco Bay and a neighborhood in the City and County of San Francisco. Built in 1936–37 for the 1939 Golden Gate International Exposition, the island's World's Fair site is a California ...

near

San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...

, eight on the East Coast and eight on the West Coast. They would spend 30–45 days at sea regardless of weather, alternating with 15 days in port, monitoring aircraft approaching the United States in the

Contiguous Radar Coverage System Continental Air Defense Command (CONAD) was a Unified Combatant Command of the United States Department of Defense, tasked with air defense for the Continental United States. It comprised Army, Air Force, and Navy components. It included Army P ...

, an adjunct to the

Distant Early Warning line The Distant Early Warning Line, also known as the DEW Line or Early Warning Line, was a system of radar stations in the northern Arctic region of Canada, with additional stations along the north coast and Aleutian Islands of Alaska (see Proj ...

under the Continental Air Defense Command. Their primary duty was to warn of a surprise

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

bomber attack. The AGRs were augmented by twelve radar picket

destroyer escort Destroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships. Development of the destroyer escort was promoted by ...

s (DERs) of the and classes, Lockheed EC-121 / WV-2 Warning Star aircraft, and in the Atlantic, Goodyear ZPG-2W and ZPG-3W blimps and Texas Towers. The DERs and Navy WV-2s were called Barrier Forces, BarLant and BarPac, and operated much further from the US than the AGRs; the Air Force EC-121s operated in "Contiguous Barrier" orbits between the coasts and the AGRs. By 1965, the development of

over-the-horizon radar Over-the-horizon radar (OTH), sometimes called beyond the horizon radar (BTH), is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is ...

had superseded their function, and the radar picket ships were decommissioned and scrapped by the early 1970s. The ships were: * Atlantic Squadron ** USS ''Guardian'' (YAGR-1) ** USS ''Lookout'' (YAGR-2) ** USS ''Skywatcher'' (AGR-3) ** USS ''Searcher'' (AGR-4) ** USS ''Investigator'' (AGR-9) ** USS ''Outpost'' (AGR-10) ** USS ''Protector'' (ARG-11) ** USS ''Vigil'' (AGR-12) * Pacific Squadron ** USS ''Scanner'' (AGR-5) ** USS ''Locator'' (AGR-6) ** USS ''Picket'' (YAGR-7) ** USS ''Interceptor'' (AGR-8) ** USS ''Interdictor'' (AGR-13) ** USS ''Interpreter'' (AGR-14) ** USS ''Tracer'' (AGR-15) ** USS ''Watchman'' (AGR-16) The Contiguous Radar Coverage System's picket stations were about off each coast and provided an overlapping radar or electronic barrier against approaching aircraft. While on station, the ships' operational control shifted from the Navy to the

Air Force An air force – in the broadest sense – is the national military branch that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an ar ...

and

NORAD North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection ...

. While on station, each ship stayed within a specific radius of its assigned picket station, reporting and tracking all aircraft contacts. Each ship carried qualified air controllers to direct intercept aircraft sent out to engage contacts. While on station other duties such as search and rescue, weather reporting, and miscellaneous duties were assigned. The

National Marine Fisheries Service The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the ste ...

even provided fishing gear so that the crew could fish for tuna during the season, and the ships sent daily reports of fish caught for research purposes. The ''Guardian'' class spent more time at sea than any other U.S. Navy vessels, apart from

ballistic missile submarine A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN � ...

s, averaging 220–250 days per year on patrol. To make this very high amount of sea time as comfortable as possible for the crew, all sleeping quarters were air conditioned, each officer had a private stateroom, petty officers shared two-man cabins and enlisted men slept in four-man cabins (most other USN enlisted men at the time slept in hammocks, and in large berthing compartments regardless of type of bed).

References

* Friedman, Norman ''US Destroyers: An Illustrated Design History (Revised Edition)'', Naval Institute Press, Annapolis:2004, . } {{DEFAULTSORT:Guardian class radar picket ship Liberty ships World War II merchant ships of the United States Cold War auxiliary ships of the United States