Sunday, February 11, 2007

Sunday Ship History: Watching the Sky from the Sea

It's the Cold War. The United States is trying to assess the Soviet threat and one of the conclusions it reaches is that long-range bombers may try to penetrate U.S. airspace. The U.S. and Canada build a line of radar sites across Northern Canada (the DEW line) for detection of possible inruders. Ah, but there is a limit to that line- the eastern and western sea approaches are uncovered. Part of the solution to filling in that radar gap- floating radar stations... otherwise known as radar picket ships (AGRs):
As the Inshore and Contiguous Barriers were becoming operational, the need for a third radar barrier farther out to sea as an extension of the DEW Line was recognized. Detailed planning for the Atlantic and Pacific extensions of the DEW Line began in 1955. The Atlantic Barrier became operational in 1956 and the Pacific Barrier in 1958.
The Atlantic Contiguous Barrier stretched along the East Coast from Cape Cod to North Carolina. The barrier consisted of five radar picket stations (Stations 12, 14, 16, 18, and 20) about three hundred nautical miles off the coast. Originally, each picket station reported to a separate East Coast Air Force base air defense direction center (ADDC), but over the years the Air Force reorganized its air defense forces. From 1959 onward, Stations 12 and 14 reported to the ADDC at Otis Air Force Base in Massachusetts, and Stations 16, 18, and 20 reported to the ADDC at Cape Charles Air Force Base in Virginia.

The radar picket stations on the Contiguous Barrier were, as noted, originally patrolled by DERs. The DERs were withdrawn on 31 March 1960 in favor of radar picket ships (AGRs), which had been converted from Liberty-type cargo vessels between 1957 and 1959.

For almost two years, beginning in late 1954, WV-2 airborne early warning aircraft, which were just entering the Navy inventory, supplemented the DERs on the Contiguous Barrier. In mid-1956 these highly capable aircraft were shifted to more demanding duties on the newly established North Atlantic barrier. ZPG-2W and ZPG-3W airborne early warning airships flying out of Naval Air Station Lakehurst, New Jersey, were another part of the Navy air defense effort from 1954 to 1962. Assigned to the Inshore Barrier, they provided radar coverage in the area between the DERs on the Contiguous Barrier and the ground-based radars of the Inshore Barrier.
The Pacific Contiguous Barrier stretched from Washington to central California. The barrier consisted of five radar picket stations, Stations 1, 3, 5, 7, and 9, about three hundred nautical miles off the coast. As on the East Coast, each picket station originally reported to an ADDC, but reporting assignments changed over the years with Air Force reorganizations. From 1959 on, Stations 1 and 3 reported to the ADDC at McChord Air Force Base in Washington, Stations 5 and 7 reported to the ADDC at Hamilton Air Force Base in northern California, and Station 9 reported to the ADDC at Norton Air Force Base in southern California.27

As on the Atlantic coast, the radar picket stations on the Pacific Contiguous Barrier were originally patrolled by DERs, the first DER patrol being made in 1955. The DERs began to withdraw from the Pacific Contiguous Barrier in June 1958; the last one departed in April 1959, leaving those picket stations to AGRs. Navy WV-2s also patrolled the Contiguous Barrier, until assigned to the Pacific DEW Line extension in 1957.28 (hat tip to the author - Captain Joseph F. Bouchard, U.S. Navy)
This Sunday Ship History is about the AGRs, filling their important but mind-numbingly dull duty at sea, watching the sky.

The radar picket ship concept?
The Navy had learned, as we have noted, the value of radar picket ships during the last year of World War II, when destroyers equipped with air search radars had provided invaluable early warning of Japanese air attacks. Fast, heavily armed destroyers had been needed to escort the attack carrier task groups, which were always the first to sail in harm’s way, but smaller, more economical ships could be used as radar pickets for slower amphibious and replenishment groups. Design studies for the radar picket destroyer escort (DER) were begun in the last year of the war. Seven Buckley-class destroyer escorts (DEs) were converted to DERs in 1945, but by 1947 six had been decommissioned and the seventh relegated to reserve training duties. Although they were in commission for only a short time during the war, these ships had proved the radar picket destroyer escort to be an efficient and effective type.

The Navy decided it needed DERs again in 1949, when it was tasked to guard the seaward approaches to the northeastern United States as part of the limited LASHUP air defense system established in 1948. Rather than recommission the Buckley-class DERs, whose World War II–vintage electronics suites were now obsolete, the Navy decided to convert mothballed Edsall-class DEs, whose diesel engines gave them twice the endurance of the steam-powered Buckleys.
See here for more on WWII radar picket destroyers (among other things).

The DERs were replaced by converted Liberty ships, the AGRs:
The Guardian-class AGRs were converted from Liberty ships between 1957 and 1959 at the Philadelphia, Norfolk, Portsmouth, and Charleston Naval Shipyards. They were 441 feet in length, displaced 10,750 tons fully loaded, and were the last ships in the Navy to have triple-expansion, reciprocating steam engines. Originally designated YAGRs (ocean radar station ships), they were redesignated AGRs (radar picket ships) in September 1958. Equipped with the large AN/SPS-17 long-range air search radar, height-finding radar, TACAN, electronic surveillance systems, and extensive communications equipment, the AGRs had a crew of from thirteen to twenty officers and 138 to 150 enlisted men, under a lieutenant commander. A large combat information center contained radar repeaters, large vertical plotting boards, and dead-reckoning tracers for tracking contacts and controlling interceptors. Their only armament was two Mark 22 three-inch antiaircraft guns and .50-caliber machine guns. The large size of the AGRs enabled them to offer comfortable accommodations: one or two–officer staterooms, three or four–man chief petty officer compartments, large enlisted berthing spaces, an enlisted dining area that could seat half the crew at a sitting, and ample space for recreational activities.

The sixteen AGRs were divided equally between Atlantic and Pacific. Radar Surveillance Squadron 2 (RADRON 2) patrolled the Atlantic Contiguous Barrier and the SOUTHERN TIP station. Originally homeported in Newport, RADRON 2 shifted in September 1958 to Davisville, Rhode Island, on the western side of Narragansett Bay. In the Pacific, Radar Surveillance Squadron 1 (RADRON 1), based in San Francisco, patrolled the Pacific Contiguous Barrier.

Atlantic Contiguous Barrier patrols normally lasted three to four weeks; Pacific Contiguous Barrier patrols were slightly longer, four to five weeks. Inport periods between patrols were normally three or four weeks long, and the AGRs spent up to two hundred days per year under way. Like the DERs, the AGRs did not carry doctors, so medical emergencies had to be evacuated ashore. U.S. ports were nearby, but the slow speed of the AGRs sometimes delayed arrival within helicopter range of shore. The weather was no better for the AGRs than it was for the DERs. One writer has described the “stark and often ferocious waters” in which the AGRs patrolled:

Bad weather and sea conditions were the rule rather than the exception for the AGRs. The storms of the North Atlantic and North Pacific sometimes brought winds of 70 to 80 knots and seas of 40 to 50 feet in height. In the North Atlantic, the winter season brought temperatures below freezing; ocean spray whipping across the ships could, and often did, coat them inches deep in ice. In the spring and early summer, the additional hazard of icebergs and growlers were [sic] often a distinct possibility.
When on radar picket patrol, the AGRs operated under CONAD control and reported unidentified air contacts to the air defense direction center designated for their picket station. The AGRs occasionally made radar picket patrols off the east and west coasts of Canada and participated in exercises with Canadian naval and air defense forces. U.S. Air Force air intercept control officers were embarked regularly for familiarization and cross training. AGRs were also tasked with weather reporting and search and rescue duties, and they took part in Atlantic and Pacific Fleet ASW exercises.
Their story is not completely untold - see here and YAGR's Association. The latter site sets the tone for ships that sailed at slow speeds in predefined boxes:
To help avoid boredom on these long periods at sea, each ship came up with ingenious ways to entertain the crew. During periods at sea, fishing tournaments would be held, shooting practice, skeet shooting, swim call and, of course, sun bathing on the the southern stations would help pass the time. As they were converted freighters, there was plenty of space aboard ship. All ships had a movie theater set up in one of the cargo holds. The other cargo holds were put to good use as basketball courts, archery ranges, weight lifting rooms, libraries, wood working shops, volley ball courts or anything else the crews could come up with. One ship even had a small swimming pool.

Even with all the above, it was still tedious and boring duty.
SPS-17 radar photo and "rough seas" photo from USS Searcher site, which also boasts:
The Searcher was the only ship that could brag of having a swimming pool. It was around 30 ft square and 3 feet deep just forward on the main deck. I can remember cooling off in that salt water on hot days. Other recreational activities included fishing off the fantail (usually shark), a basketball half court and weight room, and a movie theater below decks.
Even operating with 220 psi boilers and reciprocating engines, the AGRs had some engineering issues, as indicated in this report on how USS Searcher lost her screw at sea after a yard period:
On dry dock, certain grave formalities must be gone through. For the AGRs one of these was the removal of the propeller from the tail shaft, checking the stern tube bearing for excessive wear, and checking the shaft keyway to ensure that the key had been "spooned". "Spooning" was very important as it was a method of insuring that stress concentrations would not be initiated in the key way. Slightly more than 100 of the 2700+ Liberty Ships built had lost propellers from tail shaft failure. Analysis by the American Bureau of Shipping indicated a critical vibration speed of about 102-105 RPM when the propeller came partially uncovered in a seaway and many shafts had broken starting at keyway stress points. To minimize the possibility of failure, The Navy limited the AGRs engine speed to 66 RPM, reduced from design full speed of 76 RPM. Stern tube clearances were acceptable and a visual check of the shaft taper showed "spooning" had been accomplished and the shaft had no apparent cracking. As a final test, the shaft taper was magnetic particle tested. A heavy coil of insulated cable attached to a large storage battery was wrapped around the taper, forming an electromagnet. The area to be tested (the keyway), was sprinkled with a magnetic powder. The powder would orient itself in the form of distinct lines, showing any cracks. The test showed no cracking, but the cable ends drew a large arc on the polished taper creating a large gouge on the machined surface. The mechanics assured me that everything was "all right" and that they would polish the surface with a stone before reinstalling the propeller. "Dumbo" bought the explanation. In fact, smoothing the surface had not corrected the stress concentration point that the gouge had created in the shaft itself.

Out of dry dock SEARCHER went off to complete her overhaul. In March 1964, SEARCHER lost her screw at sea.

Eventually, technology eliminated the need for these ships and they were retired. Though there are those of a certain level of paranoia (and not much in the way of prognostication skills) that wants them back. More info on the FPS-117 radar here.

These trusty ships put in a lot of sea time and their crews did their jobs in an environment made all the more demanding by iffy weather and an extra dose of tedium. They deserve a salute for a job well done.

I also commend to you a visit to the "picket ship" links here for more information on the ships, crews and their daily lives. For example, they got mail at sea both by transfer from other ships and by an occasional airdrop (see the P2 flying over?), as I learned here. And what great ship names- Skywatcher, Watchman, Investigator...

No comments:

Post a Comment