"Jumboization," AORs, and the War in Southeast Asia
The acceptance and implementation of the fast combat-support concept opened the door for new ways of thinking in the U.S. Navy with regard to the doctrine of auxiliary ship utilization. As AOEs were added to the fleet, it would no longer be necessary for fleet oilers to keep up with a battle group; instead they could be kept out of harm's way shuttling back and forth between the sources of supply and the fast combat-support ships at sea. Except for the five oilers of the relatively new Neosho (AO-143) class, however, no other fleet oiler had a cargo capacity large enough to fill an empty AOE. In lieu of new construction, the navy decided to enlarge and extend the service life of its youngest T3 tankers and selected five ships of the Mispillion (AO-105) class for enlargement and modification. This was considered an economy measure that would save the navy approximately $25 million per ship--the difference between the cost of a new oiler estimated at $45 million and the conversion cost of $20 million. Unfortunately, the planned service life of the converted ships would only be extended for about ten years whereas a new ship was expected to last at least twenty years. The limited life of the conversions would come back to haunt the navy in the following decade as it tried to cope with the problem of block obsolescence in a period of great austerity.1
Conversion of the Navasota (AO-106) and Waccamaw (AO-109), the first two ships authorized, were expensed under the fiscal year 1963 budget. Launched in 1946 at the Chester yard of the Sun Shipbuilding and Dry Dock Company, they were the youngest of the numerous T3s built for the navy in the Second World War. After "jumboization," a term used to describe the splicing of a new and larger center section in a tanker to increase its capacity, the ships would emerge with an overall length of 644 feet and a full load displacement of 35,000 tons.
To accomplish this transformation, the ships were moved by tugs into a floating dry dock. First, cutting torches neatly sliced the ships in two just aft of the bow and the after section floated away. A new
Waccamaw (AO-109) was one of the last of the T3-S2-A2 oilers to be constructed. In 1964 she was enlarged and modernized by the addition of a midbody section, which lengthened the ship to 664 feet overall. Note the outriggers that replaced the earlier refueling booms. (U.S. Naval Institute)
midbody was then floated in, properly positioned, and welded to the old bow. Next, the 190-ton superstructure amidships was lifted from the old midbody to the new section. The original section was then cut from the old midbody and floated away. In the final step of the transformation, the new midbody with old bow and superstructure now attached was floated into the dry dock, raised, and welded to the old stern. Modifications, including a new counterbalanced rudder, new struts, and shorter propeller shafts, were made to the stern to compensate for the longer underwater body.
The latest in fueling and replenishment-at-sea equipment was installed to complete the conversion. These included kingposts with outriggers, ram-tensioned span wires and highlines, heavy-weather rigs with up to three hundred feet for either hose or wire at each station, electric-hydraulic winches in place of the old steam winches, and a helicopter platform on the forward weather deck. Each fueling station was equipped with new 7-inch lightweight hose, and the pumping capacity was improved by installing larger cargo pumps and piping.
Conversion of the sister ships Mispillion (AO-105), Passumpsic (AO-107), and Pawcatuck (AO-108) followed in FY 1964. All five would later be transferred to the Military Sealift Command where they would serve until well into the late 1980s--a remarkable testament to the excellence of their original design and the skill of the builders.
During the 1960s, many of the Essex-class aircraft carriers of World War II vintage were modified into antisubmarine warfare (ASW) support carriers (CVSs). To support this class of ships, a new type of replenishment oiler was developed around the needs of the CVS task force.2 Classified as AORs, they were designed to provide rapid replenishment at sea of petroleum and munitions and had a limited capacity for provisions and freight. Though similar to the AOE in concept, economy measures limited the capabilities of these ships, especially with regard to speed. Roughly two-thirds the size of the AOE, they had a much smaller ammunition capacity and were limited to only 20 knots. The latter was a major cost-saving measure, since the ship's machinery requirements were reduced from the extraordinary 100,000 s.h.p. installations of the Sacramento class to a moderately powerful, 32,000 s.h.p. installation more typical of those in use on commercial vessels.
Ordered under the FY 1965 building program, the first of these, the Wichita (AOR-1), was laid down on 18 July 1966. Commissioned on 7 June 1969, she was first of seven AORs that would be constructed over a period of ten years. The last, Roanoke (AOR-7), did not enter service until October 1978 and was the only ship built by National
Ordered under the FY 1965 building program, Wichita (AOR-1) was the first of seven replenishment oilers constructed over a ten-year period. Although similar in function to an AOE, the AOR at 20 knots was a much less capable ship, although it was also much less expensive to build. (U.S. Naval Institute)
Steel in San Diego. All the rest were constructed by General Dynamics in Quincy, Massachusetts.
In addition, three Cimarron-class tankers--all originally built by Bethlehem Steel, Sparrows Point--were converted to AORs through the "jumboization" program initiated in 1963. The Ashtabula (AO-51), Caloosahatchee (AO-98), and Canisteo (AO-99) were enlarged by adding a new midsection that increased their liquid cargo capacity to 184,524 barrels and provided extra space to store 175 tons of munitons and 100 tons of refrigerated stores.3
Not all the AORs were built to support CVS task forces. In an attempt to reduce expenditures in the post-Vietnam era, it was thought that they could be used as low-cost substitutes for the AOEs, which were horrendously expensive costing approximately $70 million apiece in 1966 dollars! The reason for assuming the AOR might be able to perform the AOE mission can be traced to the operational experience gained in the latter half of the Vietnam War when Wichita became the first AOR to deploy on Yankee Station.4
The slower speed of the AOR was not a problem since the carriers were not going anywhere, and Subic Bay was nearby. The small ammunition stowage capacity of the Wichita and her limited ability to transfer large amounts of ordnance was not satisfactory, however, as the carriers required up to 600 tons of ordnance per replenishment. The problem was temporarily solved by jury-rigging additional transfer stations and increasing the amount of deck cargo carried. Once these changes were made, the Wichita performed like an AOE as far as the carriers were concerned, but there were safety problems to consider. Large quantities of ammunition would be stacked loosely on the weather decks and starboard transfer rigs were crossed over to the portside in order to double the number of ammunition rigs to the carrier.5
Underway Replenishment during the War in Vietnam
From a logistics-at-sea standpoint, Vietnam proved to be a replay of the Korean War. Once again the carriers proved to have a gluttonous appetite for jet fuel and consumed ordnance at a prodigious rate. Unlike Korea, flight operations were continued around the clock with second-generation aircraft that were now capable of carrying extraordinary bomb loads in comparison to all previous campaigns. In one month alone, the Enterprise (CVN-65) expended 4,478 tons of air-to-ground munitions whereas her World War II predecessor dropped only 2,000 tons of bombs in the entire war.6
As in the earlier conflict, the support ships remained relatively few in number although the number of ships deployed doubled in size. The operations of the Seventh Fleet off Southeast Asia could only be sustained by making the most efficient use possible of all the support ships available. This was particularly true in the case of the underway
replenishment types, many of which were reaching the end of their useful lives.
The task of scheduling, coordinating, and controlling these operations fell under the command of the Logistic Support Group (TG-73.5). This was a temporary command held alternately for a period of two to three months by the commanders of Service Squadrons 5 and 7 who rotated with the assistant chief of staff for readiness of Service Group Three. This policy allowed the squadron commanders to gain practical knowledge of the extensive UNREP activities conducted off the coast of Vietnam and provided operational command experience. The insights gained from this experience provided a perspective that gave these commanders valuable lessons that could be used to better train and prepare the ships in their commands for deployment upon their return.
As operations intensified, it became apparent that the constant change in command was a major disadvantage that brought with it a lack of continuity and created problems within the service squadrons during the extended absences of their commanders. To remedy this situation, Service Squadron 9 was established in January 1969 with a commander assigned for a one-year tour of duty.
In the early stages of the conflict, fleet oilers, usually two in number, would be engaged in a five-day replenishment routine that commenced at either of the two major operation areas off the coast of South Vietnam code-named Dixie and Yankee Stations. Departing from Subic Bay in the Philippines, the first oiler would steam to a rendezvous with the carrier task group or groups operating within Dixie Station. Refueling the task group on the first day, she would then swing clockwise through the Market Time area (see map 2) replenishing along the way on day two. Returning to Dixie Station on the third day, she would steam south along the coast to An Thoi on the fourth day, and return to Dixie Station on the fifth day. A second oiler from Subic Bay would rendezvous at Yankee Station where she would replenish the carrier task groups on the first day. Then she would swing clockwise through the northern Market Time stations and into the Gulf of Tonkin on the second day, return to Yankee Station on the third day to replenish the units there once more, and perhaps consolidate with an incoming oiler before returning to Subic Bay.
As the carrier striking power was shifted north in the summer of 1966, the pattern of underway replenishment changed. By then, airfields ashore had developed to the point where the air force and marines could handle the vast majority of support missions within South Vietnam itself and the carriers were shifted north to concentrate on targets within North Vietnam proper. The typical replenishment cycle now became 3,300 miles in length and took approximately twenty-one days. Starting in Subic Bay, the first stop was on Yankee Station. While in this area, replenishment ships steamed another two hundred
Map 2. Replenishment cycles, 1965 to early 1966 (after an original in the Naval Historical Center)
miles north into the Gulf of Tonkin to refuel the ships on air rescue stations or in the positive identification radar zone whose tasks included air surveillance and control. After leaving Yankee Station, the ship would proceed along a thousand miles of coastline replenishing naval gunfire support, amphibious, and Market Time ships, and then return 1,300 miles back to Subic Bay for resupply (see map 3).
As in Korea, the navy soon found the low pumping rates and jet fuel capacity of its oilers to be inadequate--this meant long times alongside the carriers. In June 1967, commander Service Group Three implemented a revised oiler rotation plan to improve the utilization of the greater pumping capabilities of the AO-143 class and the jumboized AO-105 class. These larger oilers remained in the vicinity of Yankee Station for their entire replenishment cycle. As shown in the accompanying table, they were equipped to deliver aviation fuel at much greater rates than their Korean War predecessors. Under the new plan, the smaller AO-22 class oilers (the Cimarrons of World War II vintage) left Subic Bay and transited to the southernmost Market Time area, and from there proceeded north replenishing ships along the coast and up in the Tonkin Gulf. Then they went to Yankee Station to transfer remaining fuel to the larger oilers or an AOE, returning to Subic Bay for resupply.
The replenishment activities recorded for Ponchatoula (AO-148) during one eight-month deployment in Southeast Asia provides a good idea of the extent of the work conducted by the oilers and is typical
Map 3. Replenishment cycles after June 1967 (after an original in the Naval Historical Center)
of the operations conducted by the new ships. During this period the Ponchatoula conducted 484 underway replenishments to 503 ships, transferring fifty million gallons of fuel and 69 tons of freight. She conducted twenty underway replenishments and one consolidation with another oiler in a single day in November, transferring 2,680,000 gallons of fuel oil and 653,000 gallons of jet fuel during a 24-hour period (see table 24).
Fueling at Sea Comparisons for Korea and Vietnam
Korea (1952) Vietnam (1968) Class: Essex Forrestal UNREP: Every 4 days Every 3 days Hoses rigged: 2 6-inch NSFO 3 7-inch NSFO 1 4-inch avgas 2 7-inch JP-5 Typical transfer: 7,000 bbls NSFO 10,000 bbls NSFO 3,500 bbls avgas 10,000 bbls JP-5 Typical time: 3 hours 2.5 hours SOURCE: Miller, "Mobile Logistic Support for Aircraft Carriers," 54.
AOEs on Yankee Station
When the planes from the aircraft carriers Ranger (CV-61), Coral Sea (CV-43), and Hancock (CV-19) commenced routine bombing of North Vietnam on 7 February 1965, the Sacramento, the navy's newest UNREP ship, was in the Tonkin Gulf on her first deployment. The advantages of an AOE over an Underway Replenishment Group (URG) were immediately appreciated by the carriers. Instead of making three stops with as many ships, the carriers could simultaneously refuel, rearm, and reprovision from the single AOE. This reduced the time spent alongside for UNREP to only one-third and reduced the number of replenishment ships required.
The Sacramento could only be deployed for six months during 1965 and was the only AOE in the fleet until the Camden (AOE-2) arrived in the summer of 1966. With the Camden in theater, the two AOEs traded off, each spending six months serving TF-77 on Yankee Station until the Wichita (AOR-1) joined the force in early 1969.
Its main deck piled with ammunition and fuel lines spanning a choppy sea, the Sacramento replenishes the aircraft carrier Ticonderoga (CVA-14) on Yankee Station. Note the six fuel hoses and two Burton rigs deployed as the AOE simultaneously supplies black oil, aviation fuel, ammunition, and stores. (U.S. Naval Institute)
The brief summary that follows provides further details on how these ships were deployed and operated during the conflict:
The Camden departed Long Beach 28 May 1968 enroute to her second deployment in Western Pacific. Her first stop was the Naval Supply Depot Seattle, Washington where provisions and stores were loaded. The ship moved to the fuel pier at Manchester for POL (petroleum, oil, lubricants) loadout and then to Naval Ammunition Depot Bangor to complete ordnance loadout. Missiles and special weapons had been previously loaded aboard by Naval Weapons Station Seal Beach. The ship departed Bangor on 10 June for Subic Bay arriving on 26 June.
After completing her load requirements Camden departed Subic Bay for her first "line period" on 2 July servicing Yankee Station, Market Time/NGFS and Sea Dragon. On 11 August the ship again departed Subic Bay for her first line period under the Dedicated AOE Yankee Station Concept. Under this concept the Yankee Station replenishment schedule was divided into a three day cycle with each carrier being serviced every third day. The three carriers were serviced during the first two days with Camden consolidating from an AO and an AE on the third day. Stores and provisions consolidations were scheduled when needed and as the supply ships were available. Although the work load was heavy under the Dedicated AOE Yankee Station Concept, it was relatively easy to plan on each day's events as to times and number of customer ships. Depending upon the desires of the carrier, Camden would either join the formation or remain about 8-10,000 yards away in the direction of the expected replenishment course. Except during the period when speeds in excess of 20 knots were needed for launch and recovery, Camden would remain with the carrier until she took tactical command and assigned the AOE a station for replenishment. This practice allowed the carrier a greater latitude in rendezvous points which were necessarily adjusted to prevent mutual interference with other CVAs, especially during the Monsoon when wind and sea conditions dictated the direction of the replenishment track.7
The Camden was scheduled for a total of six line periods under this concept. All were completed successfully except for the fourth, which was terminated on 26 November following a collision with the Hancock, which resulted in the unexpected transfer of two planes from the Hancock to the Camden's deck. This forced Camden to proceed to Subic Bay in order to offload the unwanted aircraft before steaming to Yokosuka, Japan, to effect repairs. The Camden returned to Subic Bay to complete her last two line periods before departing for Long Beach on 22 February 1969.
Strikedown of Air Ordnance
During the Korean conflict, the problem of rapidly clearing ammunition from aircraft carrier hangar decks was identified as one of the key
Comparison of Ordnance Handling, Korea and Vietnam
Korea Vietnam Ammo transfer Number of UNREP stations 3 4 Rigs 2 Burton
1 Modified Housefall
4 Burton UNREP: Every 4 days Every 3 days Tons transferred 260 450 Tons transferred per hour 126 175 Typical time alongside 2 hours 21/2 hours Ammo strikedown Load configuration Nets and slings Palletized Tons per hour 30 55 Hours per UNREP 8 8 SOURCE: Miller, "Mobile Logistic Support for Aircraft Carriers," 56.
factors limiting the effective transfer of ordnance at sea. The slow "strikedown" and "strikeup" of air ordnance led to the development of a new handling concept based on the advantages of palletization. In April 1957, a large-scale test of this concept was conducted between the Paricutin (AE-18) and the Lexington (CVA-16). This demonstration showed that the transfer of palletized ordnance was one and a half times as fast as net or sling loads of bombs with palletized ordnance being cleared from the hangar deck at twice the rate of nonpalletized cargo.8
When the Sacramento and the Camden deployed to Southeast Asia, they were equipped with the same type of ship-to-ship cargo rigs as had been employed in the Korean War (see table 25). Although most of the ordnance transferred at sea was palletized, none of the carriers was outfitted to strikedown the munitions transferred via this means directly into their magazines. Nevertheless, palletization proved to be a much more efficient means of handling munitions doubling the amount of ammunition that could be handled during UNREP and allowing the hangar deck to be cleared much more quickly.
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