The Korean War Experience and the Neosho Class
AOs of the Military Sea Transportation Service
When the United States emerged victorious from World War II, the government had become the owner and operator of the largest fleet of merchant ships in the world, with 4,919 built between 1939 and 1945 under the authority of the U.S. Maritime Commission.1 While some of these ships had fallen victim to enemy action, the vast majority remained in the hands of the government as had happened at the end of the First World War. To dispose of these vessels, Congress passed the Ship Sales Act of 1946. In the following year, the navy received a windfall of thirty T2 tankers when ownership of these vessels was transferred from the maritime commission to the Navy Department. All were commissioned as navy oilers (hull numbers AO-111 to AO-142) and assigned to the Naval Overseas Transportation Service. The ships were soon pressed into service transporting refined petroleum products from refineries in the Persian Gulf.
During the war, most of the NSFO (navy special fuel oil), diesel, and avgas consumed by the fleet had originated in refineries located in the Western Hemisphere. The navy turned to the gulf to secure adequate supplies of fuel for the fleet in the oil "pinch" that accompanied the postwar economic boom. The shortage in the continental United States was so severe that when the cities on the East Coast ran low on oil in 1948, the navy was ordered to hand over one million barrels for their use.2 By 1950, 30 to 50 percent of all petroleum products used by the fleet was coming from the Persian Gulf. Each month, navy and chartered tankers moved up to five million barrels of refined petroleum from Saudi Arabia and Bahrain to the Mediterranean and Pacific for use by the Sixth and Seventh Fleets.
The bulk of this oil traveled in vessels allocated to the Military Sea Transport Service (MSTS), easily identified by the blue and gold striping adorning their funnels. The MSTS was born on 1 October 1949 as an amalgamation of the Naval and Army Transportation Services. Although all MSTS ships, equipment, and personnel belonged to the
navy, MSTS was responsible for providing all ocean transport wherever and whenever it was needed by the Department of Defense. As open warfare began in Korea, the demands on MSTS's assets were so great that it began relying heavily on commercial charters to meet its shipping needs. By 1953, 74 percent of its budget was paid directly to private shipping interests and it had become a hybrid mix of navy and civil service personnel, subject to both naval and civil service regulations.3
Underway Replenishment during the Korean War
In the years immediately following World War II, the navy, once again, became the victim of rapid demobilization. While facing the task of supporting the United States on a global basis, it had to contend with the problems of internal reorganization, an uneasy peace, and a nationwide desire to forget the war and any talk of being better prepared for the next. The financial and personnel cutbacks were so severe in the postwar period that the navy found itself temporarily forced to abandon mobile logistic support as a practice. By default, the overseas base once again found itself responsible for providing logistic support to the fleet. The situation was not altered until the outbreak of the Korean War. Once war began, Service Squadron 3 (ServRon 3), established ten days after war hostilities commenced, began to reconstruct a mobile logistic support capability. The same ships that had served so faithfully during the previous war were taken out of the Reserve Fleet and pressed into use. The doctrine of replenishment at sea had to be relearned by the fleet and old skills retaught to new hands. Fortunately the time between the wars was brief, and mobile logistic support was made readily available as soon as the ships of the service force could be reactivated.
Although units of the Seventh Fleet had been refueled and armed in port during the first days of action, the need to keep the carriers on line and close to the source of action brought a rapid return to resupply at sea. Despite a shortage of oilers and ammunition ships in commission, underway replenishment was quickly begun. The first of these operations was initiated on 23 July 1950 when Task Force 77 refueled at sea south of Cheju Do.4 By year's end, fleet oilers of ServRon 3 had met the ships of the Seventh Fleet on seventy-two occasions and had completed no less than 100 carrier, 11 battleship, 50 cruiser, and 546 destroyer fuelings. Underway replenishment (UNREP) was not limited to fuel alone as ammunition ships (AEs), primarily the Mount Katmai (AE-16) and the Paricutin (AE-18), transferred a total of 7,665 short tons of ammunition to the task force during this same time period.5
Although the forces employed in Korea were smaller than those employed in the Second World War, in some respects the logistic effort surpassed that of the longer, world-encompassing conflict. The
aircraft sortie rate was higher, combat employment of carriers was on a more continuous basis, and the amount of ordnance expended was greater. From June 1950 until July 1953, naval aviators flew 275,912 sorties to expend 176,929 tons of bombs, 271,890 rockets, and 73,888,000 rounds of ammunition while making over 850,000 runs on targets.6 Although the total number of sorties of naval aircraft were less than the totals in all theaters of World War II, more than 74,000 tons of bombs and 60,000 rockets were dropped on the enemy. The at-sea logistic effort required to support these expenditures was one of the unheralded achievements of the Korean War.
Underway replenishment of fuel, ammunition, and stores allowed the carriers of Task Force 77 to remain on station in the Sea of Japan for up to three days at a time throughout the conflict. On the fourth day the carriers rendezvoused with the replenishment force in the lee of Ullung Island about one hundred miles south of the 39th Parallel to top off with fuel and replace the huge stocks of ordnance expended by aircraft during the intensive air strikes needed to support the hard-pressed ground forces. This avoided what would otherwise have been a 1,600- to 1,700-mile roundtrip to the carrier base in Yokosuka, Japan.7
One loaded oiler was kept on station in the operating area at all times during the campaign to supply the fuel needs of the task force on a continuing basis. In addition, at least two other fleet oilers were usually assigned to the fueling group, one functioning as a standby tanker while the other shuttled to the advance base at Sasebo, Japan, for more fuel. The role of fueling standby and shuttle tanker was alternated between the three oilers. After three days in the operating area as the on-station oiler, an oiler then spent one day returning to port, and one day refilling before returning to the operating area where it relieved a second shuttle oiler becoming the standby ship. Fleet oilers normally cruised fully loaded at 15 knots, though they sometimes operated for protracted periods at their maximum speed of 18 knots fully loaded.8
As operations progressed, it quickly became evident that the limiting factor in the time needed for refueling at sea was the rate at which gasoline could be transferred to the Essex-class carriers. The introduction of jet aircraft--two of the four squadrons carried by the large carriers were now jet powered--had dramatically increased the amount of aviation fuel consumed during the air operations routinely conducted by the carriers. Although these aircraft had been modified to burn avgas, the only aviation fuel then carried aboard ship, they gulped fuel at a rate four times greater than their propeller-driven cohorts! Yet when war broke out, the delivery of avgas was limited to the same 4-inch diameter hose that had been used in World War II. The aviation fuel problem was so acute during the first six months of fighting that on at least two occasions the pumping time
needed to fill the depleted gasoline tanks on board the Valley Forge (CV-45) exceeded five hours. The frequency of gasoline replenishment required by the fast carriers was so great that it limited the normal replenishment rate of these carriers to one day out of three, thereby reducing the average availability by one-third. This was considered excessive "in view of the trend in close [air] support and interdiction operations [which] required aircraft on station around the clock." A temporary solution was attained by authorizing the addition of a second 4-inch hose line to gear carried by the oiler. This doubled the rate at which avgas could be discharged and reduced the time needed for replenishment, but did not solve the basic problems of avgas distribution since safety considerations involving this highly volatile fuel continued to impose severe limitations on tank pressures and linear flow rates for high-octane gasoline. This contributed, no doubt, to the adoption of HEAF (later JP-5) jet fuel, a much less volatile fuel similar to kerosene. It was better suited for jet aircraft and made fuel handling much easier for the replenishment ships.9
Ammunition proved less of a problem because the carriers of Task Force 77 were fitted with three transfer rigs instead of the one rig used in World War II. After working with the same ammunition ship for several replenishments, the carriers found that they were able to receive ammunition at the rate of 125 tons an hour during fair weather operations in daylight hours. It took only two hours alongside to transfer the 250 tons of ordnance--the amount generally needed to be taken aboard every four days.10
Thus, by 1952 it had become possible to replenish the entire fast-carrier task force in the space of nine hours, although it was usually an all day operation that took ten to twelve hours to complete. This was followed by many more hours of hard work on the carriers "striking down" ordnance to clear the hangar deck so that planes could be respotted and air operations resumed. Slow strike down of air ordnance quickly became one of the critical limitations of underway replenishment as was the pumping time to transfer the copious amounts of avgas consumed by the air group. Nighttime replenishment, once considered so dangerous as to be impracticable because of the need to darken ship, was now a routine operation and it became standard practice for the first ships to come alongside the tankers before daybreak. (The advent of radar and the realistic appreciation of its use by the enemy had brought a relaxation of darken-ship requirements and the use of screened lights.)
The 1952 Conference on Mobile Logistic Support
The magnitude of the problems encountered while attempting to keep the ships of Task Force 77 supplied at sea while on station in the Sea of Japan resulted in the call for a special conference on mobile logistics. This meeting was convened at the request of the CNO in Washington,
General Characteristics of the AO-143 Class (as Proposed)
Characteristics: Displacement 36,000 tons Length 655 feet Speed fully loaded 20 knots Replenishment speed 17 knots Can transfer simultaneously: 720,000 gph-Black 200,000 gph-Avgas 180,000 gph-HEAF 120,000 gph-Diesel Fueling stations: 8 Replenishment stations: 2 midship Fueling at sea cranes being considered. Typical [CV] replenishment would use: 2-7" hoses-Black 360,000 gph 1-7" hose -HEAF 180,000 gph 1-6" hose -Avgas 100,00 gph
SOURCE: "Report of Committee No. 2," Conference on Mobile Logistic Support, 19 May 1952, CNO-1952 File, Command Files Post 1 January 1946, Operational Archives Branch, Naval Historical Center, Washington, D.C.
D.C, on 28 April 1952. The conference opened with presentations given by the Ship Characteristics Board, the Logistics Research Unit, the commander of the Service Force, Atlantic Fleet (ComServLant), and representatives of his counterpart in the Pacific (ComServPac). The attendees then broke into three working groups to study a series of specific questions about mobile logistic support.11
The issue of carrier replenishment was taken up by Committee No. 2, which was charged with evaluating matters pertaining to AOs, AORs, AEs, and CVs. Although the navy had more than enough T3-type tankers to meet its needs for the foreseeable future, it was clear that these ships lacked the speed, cargo capacity, and transfer rates needed to satisfy the demanding logistic requirements of modern air warfare as conducted by the Essex-class carriers on Task Force 77 during the conflict in Korea. No longer hampered by a lack of funds, the navy resurrected plans to build a new fleet oiler--the first to be designed from the keel up since the Kanawha was laid down in 1913. Thus, the first item on the committee's agenda concerned the general characteristics proposed for the new ship designated as the AO-143 class. The committee was asked to evaluate its characteristics with particular attention being paid to the proposed refueling data. These are shown in table 22.
The committee agreed that the projected design was highly satisfactory, although it recommended that the adoption of cranes be delayed until after the installation of the first unit scheduled for placement aboard an existing oiler in January 1953 be proven. Other recommendations made by the committee included:
- The necessity of altering existing oilers to increase transfer rates
- The need to standardize on a single refueling method
- The Conecuh conversion
- Characteristics of a new AE design
- Recommendations for new handling methods for ammunition (use of fork lift trucks, palletization, etc.)
- Improvements in transfer rates from existing AEs
- Continued development of the constant tension rig12
These recommendations were consistent with the objectives set forth by the commander of the Service Force, Pacific Fleet, who summarized the program to improve underway replenishment in the following general terms:
First, to minimize the time required to transfer needed materials, in the proper amounts to the combatant ships of a task force at sea; and second, to reduce the restrictions imposed by weather, sea and visibility conditions when such operations can be carried out successfully and with acceptable risk.13
ComServPac was convinced that the optimum performance from issuing ships could only be attained from ships designed from the keel up. So important were the principles of underway replenishment to the concept of "all-oceans" naval operations "that ComServPac adopted the same care and attention in their design as was then accepted as a matter of course in the case of combatant types."14
The Neosho Class AO-143
The fourth Neosho (AO-143) was laid down at the Fore River Shipyard of the Bethlehem Steel Company in Quincy, Massachusetts, on 15 August 1952. She was launched on 10 November 1953 under the sponsorship of Mrs. John S. Phillips, wife of Rear Adm. John S. Phillips who had so gallantly commanded the second Neosho (AO-23) until her tragic loss in the Coral Sea.15
The Neosho and the five others of her class that followed were the first oilers in the U.S. Navy to be engineered specifically for underway replenishment. They were basically similar in design to the Cimarron class except that they were larger and faster. Displacing over 36,000 tons under full load, they carried one-third more cargo than their predecessors and were designed to cruise at 20 knots. The liquid cargo to be carried was 69 percent fuel oil, 28 percent aviation fuel (initially avgas), and 3 percent diesel fuel. Unlike the Cimarron, which had been modified after construction to handle gasoline, the cargo tank arrangement of the new ships was designed expressly to meet the particular needs of this liquid. Since it was undesirable to put saltwater ballast in the tanks normally used to carry gasoline, a design was devised that placed the tanks on the centerline amidships so that
The third oiler to be christened the Neosho. Launched on 10 November 1953, she was the last "straight" oiler to be designed for the U.S. Navy. (U.S. Naval Institute)
ballasting was not required of these compartments. A cofferdam was constructed around the gasoline tanks to prevent contamination and the gasoline tanks were surrounded by black oil and diesel tanks to afford some protection to the highly volatile gasoline. Laying out the cargo tanks in this manner allowed the ship to be kept in proper trim by ballasting only the black oil tanks.16
As the design took shape, it became apparent that it would be "deadweight critical," that is, would be brought down to its design draft by its deadweight items, principally liquid cargo, before its tanks were filled. This excess of volume for cargo permitted a flexibility advantage not usually found in oilers. It allowed the carrying of a design load with wing tanks filled only to the design waterline, thus preventing heel due to runoff in the event of damage. It also permitted the ships to carry greater loads in the event of an emergency.
One of the most important features influencing the design of this class was the need for a cargo deck--one designed from the outset with the needs of underway replenishment in mind, as opposed to the haphazard additions placed atop the well deck during World War II. In recognition of the need to handle nonliquid cargo, the cargo deck on the new oilers extended from the forecastle to the poop the full beam of the ship and was equipped with two midship transfer stations for moving dry cargo by Burtoning, or highline. The cargo deck, which had a clear fore-and-aft passage to facilitate movement
Fig. 14. Close-in rig
Fig. 15. Spin-wire rig.
of cargo, also provided support for the eight fueling rigs designed to dispense liquid fuels through a newly developed 7-inch lightweight hose. Extra stowage space was provided below decks for additional provisions that could be issued to ships alongside on an emergency basis.17
Fig. 16. Oiler inhaul rig
Improvements to the Fueling Rig
Absent from the recommendations that emerged from the conference on Mobile Logistic Support was any discussion of the possible improvements to the fueling rig, although it was suggested that the fleet standardize on a single method of refueling at sea. This item was brought to the attention of the committee because of the different methods then being employed by the Pacific and Atlantic Fleets. The former preferred to use the Elwood method, also known as the span-wire rig, while the latter preferred the "Elokomin method."18
Developed and implemented in the last months of the Second World War, the Elwood method used a heavy span wire rigged between the two vessels to support the fuel hose (see figs. 14-16) thereby allowing greater separation between the ships than was possible with the close-in, or alongside, method. The increased distance between the vessels permitted greater speed, provided better station keeping, and allowed more maneuverability during the operation. The Elokomin method, developed on board the fleet oiler Elokomin (AO-55) after the end of World War II, was a combination of the Elwood and close-in rigs. The Elokomin method also used a wire span between ships to support the fuel hose, but unlike the Elwood method, the hose and span wire were hauled over to the receiving ship by a winch on the replenishment ship. This made it easier to use with small ships because the oiler supplied the power to pull the hose and support wire across to the
receiving ship. This feature led to its being named the oiler inhaul rig.19
As a result of the ongoing problems that continued to plague the ships of Task Force 77 as they attempted to replenish in the Sea of Japan, the CNO called a meeting at the San Francisco Naval Shipyard in September 1952 to determine what corrective actions could to be taken to improve the existing replenishment systems then in use by Task Force 77 steaming in the Sea of Japan. One outcome of the San Francisco meeting was the establishment of a research project within the Bureau of Ships (BuShips) to develop a fueling rig that could be used in extremely heavy weather.20 Working with the Otis Elevator Company, Chief Boatswain Milton R. Pristach, project officer for the BuShips' Research and Development Program, came up with a counterweight system for tensioning the span wire, which allowed the fueling ships to be separated by as much as 300 feet.21 The unique feature of this system was a lead counterweight that moved up and down inside the kingpost. A prototype of this heavy-weather rig was installed in the Pawcatuck (AO-108) and tested during Atlantic Fleet exercises in October-November 1954 where it was successfully used to fuel destroyers in Sea State 5 conditions with gale winds. As reported by the commander of ServRon 2:
The device and principles were proven sound and practical beyond the most optimistic hopes of operating personnel. . . . It is believed that Fleet oilers with counterweight tensioned 300-foot heavy weather wire-tended rigs at stations 7 and 8, will provide fueling capabilities heretofore unheard of.22
The success of the tensioned fuel rig led to its installation in all fleet oilers commencing in 1956.
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