WWII-era seaplane tenders were on their way out of the US Navy by the time of the Vietnam War. However one, USS Albemarle, would have a second life as a US Army floating repair base during that conflict.
(Launching of the WWII US Navy seaplane tender USS Albemarle.) (Associated Press photo)
(The ex-USS Albemarle being converted into USNS Corpus Christi Bay (T-ARVH-1) at Charleston Naval Shipyard.)
(USNS Corpus Christi Bay during the Vietnam War.) (photo by Bob Brandt)
seaplane tenders in general
Like other navies of the upcoming second world war, the US Navy had high hopes for large seaplane tenders in the 1930s. Smaller seaplanes would be used for scouting, while a myriad of missions were envisioned for big “flying boat”-types.
Before 1941 it was thought of as unfeasible to secure, build, equip, and man new airstrips for big land-based naval warplanes….the logistical and transportation bandwidths were just not there. Instead, medium and large seaplanes would be served by new large seaplane tenders as the “forward edge” of US Navy aviation, doing not just reconnaissance but ASW missions, anti-shipping strikes, and even strategic bombing of enemy cities – all without the need for ashore airstrips, and able to move around as the war progressed.
(The two Curtis class large seaplane tenders fitting out after launch. In the foreground is USS Albemarle (AV-5) – the future USNS Corpus Christi Bay – and across the pier USS Curtis (AV-4), further along with 5″ guns already fitted.)
The US Navy was by no means unique in this mindset, and the Imperial Japanese Navy also foresaw a mission for ships of this type.
For certain, “flying boat”-type seaplanes (especially the Catalina) played a useful role during WWII. However they were not as ubiquitous or critical as had been envisioned before the war.
(USS Albemarle with Catalinas during WWII.)
The aircraft carrier became the dominant warship during WWII, and carrier-based planes supplanted the short range roles envisioned for small and medium-sized seaplanes. Shipyards in the Allied nations cranked out flattops faster and in much higher numbers then had been thought possible.
US Navy construction battalions (SeaBees) proved adept at quickly “turning around” captured Japanese airstrips for use by larger land-based warplanes, or even building them from scratch. The United States further refined this with the Argus and ACORN systems. An Argus team was a pre-staged radio and radar unit deployed as soon as a captured airfield was made ready. ACORN was even more elaborate; it was essentially an “airbase in a can” with pre-staged construction, security, communications, mechanic, searchlight, and administrative units; basically everything but planes and the dirt under the runway. By this, the niche large seaplane tenders would have filled was instead done by land-based larger naval warplanes.
Finally, while something like the PB2Y Coronado of the late 1930s would have naturally always already been at a major disadvantage, German and Japanese land-based fighters grew in range and firepower so much during WWII that the gap became a chasm and it was simply not viable to use seaplanes in many of their pre-war envisioned roles.
The “interim type” seaplane tenders had no real future and were quickly decommissioned.
(The mothballed USS Pocomoke (AV-9), an “interim type”, was decommissioned less than a year after WWII ended and never reactivated.) (photo from Life magazine)
The medium types, particularly the Barnegat class, continued in use first as seaplane tenders and then in other roles: in the USA, as cutters for the US Coast Guard and abroad in other navies, as repair ships, training ships, patrol boat tenders, and other roles; even as makeshift frigates. Some of these were still in use in the 1990s.
(The Barnegat class USS Timbalier (AVP-54) three years after WWII ended, supporting PMB Mariners.)
The US Navy had a lot of money sunk into the two Curtis and four Currituck ships; all of which survived WWII. These large warships would remain in commission.
(The Currituck class large seaplane tender USS Salisbury Sound (AV-13) handling a P-5 Marlin during the Vietnam War. These were useful for coastal patrol and sometimes carried rockets for use against Viet Cong smuggling boats. The four Currituck class ships were similar to the two Curtis class ships before them. An additional pair were cancelled near the end of WWII.)
USS Albemarle during WWII
USS Albemarle (AV-5) was the second of two Curtis class seaplane tenders, a pre-WWII design. The keel was laid in June 1939 and the ship was launched in July 1940. The name had previously been borne by USS Albemarle, a 19th century sail warship and CSS Albemarle, a Confederate ironclad of the USA’s civil war. USS Albemarle commissioned on 20 December 1940, with WWII underway but the United States not yet involved.
(USS Albemarle visiting Canada in 1941. The USA was still neutral but Canada was already at war with Germany and Italy. USS Albemarle is already painted in the uncommon and unsuccessful USN Measure 2 camouflage scheme.)
As built, USS Albemarle measured 527’4″ x 60’3″ x 21′ and displaced 8,671t. The ship was steam powered, with four Babcock & Wilcox boilers, two New York Shipbuilding turbines, and two DeLaval reduction gearboxes on two propeller shafts. The top speed was 20kts.
USS Albemarle was armed with four 5″ guns and sixteen 40mm AA guns. The 5″ guns were originally open mounts, later replaced by turrets. During WWII additional 40mm and a dozen 20mm guns were added.
Although a few “flying boat”-types could be craned aboard, USS Albemarle was less of a “seaplane carrier” and more of a mothership. Besides ordnance, aviation fuel, and spare parts; everything else in a US Navy squadron was aboard: training materials, a paymaster, a medical unit, administrative offices, a chaplain, and so on.
(USS Albemarle midway through WWII.)
During WWII, USS Albemarle‘s first mission was to Iceland, where the ship rode out a storm with 100mph winds. The rest of 1942 was centered around the Panama Canal, with USS Albemarle operating in both the Pacific and Atlantic. In 1943 and 1944, the ship operated in the north Atlantic. In 1945, USS Albermarle retrieved US Navy aircraft in Europe made redundant by Germany’s surrender in May. The ship was in the process of transferring to the Pacific fleet when WWII ended altogether in September.
For the two 1946 nuclear tests at Bikini Atoll, USS Albemarle was the main technical ship, servicing the scientific instruments of the test fleet. The ship was about 135 NM away from the actual atomic blasts.
the Seamaster conversion
(USS Albemarle’s envisioned P6M Seamaster and P5M Marlin aircraft. The latter was redesignated P-5 Marlin when the five branches of the military unified their aircraft nomenclature.)
After the US Air Force became an independent branch of the United States military, it held a monopoly on strategic nuclear weapons. While the US Army had smaller tactical-yield weapons, the strategic bombers (and later, the earliest ICBMs) all belonged to the US Air Force.
After the USSR developed its own strategic nuclear arsenal, it was largely felt that a future major war would be very brief and decided by a strategic nuclear exchange. Politically, the US Navy felt disadvantaged by this both in terms of prestige and for future Congressional funding.
The US Navy’s offering was a long-range, jet-powered seaplane. Since they could take off and land on any stretch of suitably calm water, they were immune to a Soviet surprise attack: in times of crisis they could be dispersed quickly to any number of bays, coves, river mouths, etc. It would be impossible to pre-target all these with missiles. The 1950s US Navy called the concept “SSF” or Seaplane Striking Force.
Martin’s P6M Seamaster first flew in July 1955. This “flying boat”-style jet warplane was remarkable. It had a 4-man crew and a 102’7″ wingspan, and was powered by four J75 turbojets in two twin “wing shoulder” nacelles. The Seamaster was subsonic, with a max speed of Mach 0.9 at 20,000′ and slightly less for a realistic cruising speed. It could carry two 30kT atomic bombs to an unrefueled radius of 650 NM.
This combat radius was roughly the distance to Vladivostok from American military bases in Japan and about 50% more than the distance required to hit Leningrad from NATO naval bases in West Germany and Denmark. Targets deeper inside the USSR were obviously even more out of range. For the Seamaster to seriously be viewed as a realistic strategic asset, the US Navy realized that every mission would require multiple refuelings on the inbound and outbound legs.
This would be addressed in several ways. Some Seamasters would be equipped with a “buddy kit” to inflight refuel other Seamasters carrying atomic bombs. The planes would also be refueled at sea by submarines, and by seaplane tenders. The latter would also have the ability to perform maintenance and rest the aircrews.
(The Gato class submarine USS Guavina (SS-362) sank a small Japanese warship and thirteen Japanese merchants during WWII. It was selected for the Seamaster project and renumbered (SSO-362) as an “oiler submarine” after the refueling deck seen above was installed.) (photo via navsource website)
(It was also considered to utilize leftover WWII Ashland class amphibious assault ships to complement submarines and seaplane tenders. This 1957 photo shows USS Ashland (LSD-1) conducting a proof-of-concept test with a Marlin substituting for the Seamaster.) (photo via navsource website)
On 6 February 1956, USS Albemarle was selected for the Seamaster project. The decommissioned ship was at that time in the Brooklyn Inactive Group in NYC. The conversion was carried out by Philadelphia Naval Shipyard.
The conversion was extensive. The entire stern transom area and rear deck was cut off, to fit a ramped-type runup into a semi-open aft docking bay. A Seamaster could be secured for maintenance or refueling in this manner. Seamasters could also be refueled offboard via hoses. Two of the three heavy WWII cranes were eliminated. Two of the 5″ main guns from WWII were removed. Some, but not all, of the WWII 40mm positions were eliminated as were all of the 20mm AA guns.
On 21 October 1957, USS Albemarle recommissioned in the new configuration, prepared to support the Seamaster project. In January 1958, USS Albemarle made a voyage to the Caribbean, and then to the eastern Atlantic later in the year.
By 1959 USS Albemarle was well-suited and ready to support Seamasters. However this was not to be.
Besides cost overruns and crashes of the first two planes, the SSF concept fell victim to changing military technology. Several months after USS Albemarle recommissioned, the US Navy completed design work of a strategic nuclear missile and USS George Washington (SSBN-598) was ordered. In April 1959, the UGM-27 Polaris submarine-launched ICBM was tested successfully.
(USS George Washington spelled the end of the strategic jet seaplane concept.)
Polaris was much longer-ranged, flexible, higher-yield, and infinitely more survivable than any seaplane would ever be, and filled the same strategic nuclear niche.
Also at the same time the Seamaster was being developed, the first Forrestal class aircraft carriers commissioned. These large warships could operate new naval strike jets capable of carrying tactical nuclear weapons in a psuedo-strategic role if required, and could obviously also undertake any variety of conventional war missions.
The first batch of 24 P6M-2 Seamasters was reduced to 18, of which deliveries began in early 1959. The US Navy was still supportive of the SSF concept and repurposed it to Congress as a long-range airborne minelayer. The Seamasters were now to be formed into one single squadron, seemingly defeating a lot of the logic behind the wide-dispersal concept.
In August 1959, the entire Seamaster program was cancelled. The United States spent $400 million on it ($3.56 billion in 2020 dollars) and inclusive of the rebuilds of USS Albemarle and the submarines, nearly $4.5 billion in modern terms on the whole SSF concept.
Now decades later, military historians often ponder the Seamaster in a “…what were they possibly thinking?” way, but the 1950s US Navy took the SSF concept very seriously. Even at the end, the cancellation was unexpected. Eight P6M-2 Seamasters were already accepted and another three building, and the squadron was 24 weeks away from being certified as combat-capable. Training was well underway and the cancellation was so sudden, that a few officers traveling with orders-in-hand for Seamaster duty only learned of it when checking in to their new duty station.
The rebuilt USS Albemarle now had no mission. Homeported in Norfolk, VA; the ship made sporadic sea time along the east coast for the remainder of 1959 after the Seamaster cancellation and was then used as a “flag-showing” ship in the Caribbean during 1960. Future prospects were dim, as the US Navy already had sufficient resources to support the P-5 Marlin.
USS Albemarle decommissioned on 21 October 1960 – only three years to the day, exactly, after being recommissioned. The conversion by then was considered a mistake. The ex-USS Albemarle remained in the Atlantic Fleet’s reserve until August 1962, at which time the US Navy notified Congress that there was no foreseen future use for the ship. Consequently, on 1 September 1962, the title for the ex-USS Albemarle was transferred from the Pentagon to the US Maritime Administration for long-term layup. The ship was towed to the James River, VA “ghost fleet” anchorage.
conversion to ARVH and the Vietnam War
(US Army concept model of USNS Corpus Christi Bay which was differed only in minor details from the finished conversion.)
During the Vietnam War (1960 – 1973) the US Army flew over 11,800 individual helicopters in theatre. Obviously not all were in use at the same time; none the less during the late 1960s / early 1970s there were thousands of being flown in South Vietnam at any given moment.
Never before in history had a nation deployed such a huge rotary-wing force halfway across the world. At the same time, helicopters themselves had matured compared to the little piston-engined designs of WWII and the Korean War. Even the UH-1 Iroquois (aka Huey), which was the most basic and (by far) the most numerous kind, had a turboshaft engine, modern flight instruments, and fully-metal airframe.
Normally, depot-level maintenance of helicopters was done at the Army Aeronautical Depot Maintenance Center (ARADMAC) at Corpus Christi, TX. This facility was established in 1961, when 15 disused acres and buildings of the US Navy’s WWII Corpus Christi training airbase was transferred to the US Army. At its peak, ARADMAC was the largest helicopter repair facility on Earth.
(ARADMAC during the Vietnam War era.)
Mid- and top-level repairs and upkeep of the massive helicopter force in South Vietnam was a huge headache for the United States by the mid-1960s. To even get helicopters there to begin with required a long sea journey aboard one of the converted WWII aircraft carriers.
(A US Army UH-1 Iroquois prepared for shipment aboard the converted WWII aircraft carrier behind it. Helicopters always shipped unrotored. The US Army experimented with different anti-salt spray measures: here, doped fabric; later blown plastic and finally peel-off plastic which was deemed best.)
Helicopter maintenance facilities in South Vietnam were established but were limited in what they could accomplish. Repairs were limited to the training level of soldiers there, and a lot of the special technical gear was not really amenable to being shoved around quonset huts and tents. These forward helicopter bases were already overstretched doing normal low-level day-to-day work.
(Example photo of US Army helicopter maintenance in South Vietnam. Here, a Huey’s rotor blade is being removed.)
As was the nature of the Vietnam War, helicopter staging areas made very tempting targets for irregular harassment by Viet Cong mortar teams.
There was another, political, aspect in that every dollar spent to establish semi-permanent or permanent American military buildings in South Vietnam implied the war being an open-ended affair with no light at the end of the tunnel.
When a US Army helicopter took damage, or was at its flight-hour limit for high-end upkeep; the entire process had to be reversed: the helicopter had to be made ready for sea shipment again, space aboard one of the “seatrain” chartered freighters or one of the converted WWII carriers (themselves wearing out fast) had to be found, and the helicopter shipped across the Pacific and through the Panama Canal to ARADMAC in Texas. After the repairs at Corpus Christi were done, the process repeated itself yet again as the helicopter went back to the war zone.
All of this was incredibly expensive, both in freight dollars and more importantly, in time. Repairs that actually only took a week of real-time labor ended up taking two months.
What was desired was a non-permanent way by which many or most of ARADMAC’s abilities could be duplicated in South Vietnam.
This concept was not altogether new. Late in WWII, the US Army foresaw the need to support B-29 Superfortress bombers and their P-51 Mustang escorts as the “bomber line” inched across the Pacific closer to mainland Japan. Six project “Ivory Soap” units were established, aboard ships with trained mechanics and pre-staged repair parts.
(Shipboard service to the propeller of a land-based warplane by the US Army’s 2nd Aircraft Repair Unit – Floating during WWII.)
At the start of the 1960s, the US Army considered a concept called FAMF (Floating Aircraft Maintenance Facility), a relocatable way to support aircraft far abroad. The early concept mentioned “…in Asia”, as it looked more and more likely that the USA’s involvement in the former French Indochina was going to deepen.
The FAMF concept gained support and in the early 1960s, Army Materiel Command established a top-level Project Management Office called “Project Flat-Top”. As might be guessed, “Flat-Top” originally envisioned acquiring and converting a mothballed WWII US Navy small aircraft carrier.
(As a representative example the mothballed WWII escort carrier ex-USS Salerno Bay (CVE-110) in Boston during 1961.) (photo via Christian Science Monitor newspaper)
Although the office’s name remained, this idea was soon abandoned. The Army’s “de-mothballing” costs of a WWII escort carrier would be prohibitive, and some of the reactivated ship would be superfluous to what the FAMF was supposed to be.
Instead the “Flat-Top” office studied a variety of other mothballed WWII types: LSTs, seaplane tenders, and cargo ships. Of these the seaplane tender was most ideal.
As the ex-USS Albemarle had just decommissioned, and the hull had no further interest by the US Navy, it was selected.
MSTS / MSC during the Vietnam War
The ex-USS Albemarle‘s title, which was then in custody of the US Maritime Administration, transferred back to the US Navy on behalf of Military Sea Transportation Service (MSTS). MSTS was founded in 1949 as part of the Department Of The Navy (but, not actually part of “the” active US Navy) to put all of the five armed forces various sea shipping assets under one umbrella. MSTS was renamed Military Sealift Command (MSC) in 1970; the name it retains today.
MSTS / MSC ships are not commissioned warships and thus, are prefixed United States Naval Vessel (USNS) instead of USS. Per legislation they were unarmed. They were crewed by civilian sailors and captained by a Ship’s Master of the US Merchant Marine. During the Vietnam War, MSTS / MSC ships were a mix of newer civilian merchants and converted WWII ex-US Navy types.
(As an example ship USNS LeRoy Eltinge in South Vietnam during the 1960s. This MSTS vessel had previously been USS General LeRoy Eltinge (AP-154) during WWII.)
The MSTS / MSC headquarters in South Vietnam was located in this late-19th century waterfront Saigon building, the “Dragon House”, address 1 Trình Minh Thê St. It was formerly a civilian French freight company (Messageries Impériales, hence the “MI”) during the Indochina War and during WWII, a logistics station of the Imperial Japanese Navy.
As a sidenote, as of 2020 this building (now #1 Nguyên Tat Thành St) still exists; now a small museum of Ho Chi Minh’s life. The Vietnamese restored the building to the pre-WWII appearance, removing the American radio antennas and opening up both floors of lanai which were windowed in during the Vietnam War.
During WWII, a “total war”, loss of merchant shipping was certainly viewed as part of the conflict. During the Vietnam War, Military Sealift Command’s civilian-manned presence in what was essentially a war zone became something of a legal grey zone for the American military.
(The ex-USS Albemarle being transformed into USNS Corpus Christi Bay at Charleston.)
In 1964 “Project Flat-Top” was awarded $11 million to convert the ex-USS Albemarle into the first FAMF. The work was carried out by Charleston Naval Shipyard, SC and was to be completed no later than 1 January 1966.
On 27 March 1964 the ship was renamed USNS Corpus Christi Bay, in a nod to ARADMAC in Corpus Christi. The new hull designation was T-ARVH-1.
All of the Seamaster conversion work was un-done. The ride-up stern area was blanked off with a flat transom.
The one remaining WWII crane was removed. Any remaining WWII weapons, and their rangefinders, magazines, and support gear; were removed. A pair of identical 20 ton cranes, smaller and more compact than the WWII design, were installed as seen below. There were also two smaller cranes forward.
The aft end of the ship was built up into a 24′ deep working area, topped by a 50’x150′ helipad. It was served by a hatch big enough for a whole helicopter to be craned down into the work area, and also by a small freight elevator.
(The aft working area and main helipad being constructed.)
(The large hatch being constructed.)
The forward deck had a much smaller basic helicopter landing area, called the “admin pad”. It was not connected to the main repair areas aft and was used by helicopters not involved in repair activities.
(The “admin pad” and two secondary cranes. This photo was taken during the post-conversion sea trials; a loose anchor was not normally carried on deck.)
During the conversion, all remaining WWII electronics were stripped off, as were any related to the Seamaster project. The main mast was fitted for two radars; externally similar but operating in different frequency bands. One was capable of basic nautical search but both were optimized for air traffic control. The top of the mainmast held a huge periodic log-style antenna called the “Three Four”, which was for transmit-only high frequency radio.
(The two new radars and the big “Three Four” HF radio antenna.)
Atop the forward superstructure a small air traffic control tower was built. It occupied the spot previously used by the gunnery director for the 5″ guns during WWII; now all removed.
(Close-up and location of the ATC tower.)
The internal repair area aft had 26 “production shops” and 16 “support shops”. These could accomplish most any kind of repair that a helicopter would ever need.
(One feature in the metals shop was a heat treat over where metal parts manufactured aboard the ship could be made ready for immediate use.)
The shops varied greatly. There were engine test cells where helicopter turboshafts could be run up onboard. There transmission repair facilities, a hydraulics shop, a sheet metal shop, a gunsmith, a foundry, an electronics shop, and so on. Repairs were not necessarily limited by spare parts, as the ship could manufacture some items from scratch.
But primarily, spare parts were used when possible. More than 20,000 kinds of aviation-related spare parts were carried.
(Some of the thousands of spare parts being onloaded in Texas prior to the ship departing for Vietnam.)
There was a laboratory where the purity and viscosity of lubricants and hydraulic fluids could be tested.
One notable item aboard USNS Corpus Christi Bay was a IBM 360/20 computer. Computers aboard warships were then in their infancy, and this was one of the more (by early 1960s standards) powerful computers ever sent to sea then.
This computer was 16 bit and had a 32 KB core memory. For reference, the above jpg picture file of the computer is larger than the computer itself’s core memory. None the less, during the Vietnam War it was a useful advancement.
The crew level of the ship was drastically reduced from WWII. As USS Albemarle the US Navy manning was 100 officers and 1,035 enlisted sailors. Now as USNS Corpus Christi Bay, the ship had a MSTS/MSC captain, 128 civilian sailors, and a maximum of 361 US Army soldiers. Most of the living spaces and some of the work areas were now air conditioned.
(The sick bay had a surgery room and was staffed by an Army doctor trained in aeromedicine.)
(USNS Corpus Christi Bay had a ship’s cobbler who could mend combat boots of helicopter crews.)
More than 180,000 helicopter blueprints were carried, along with a library of technical books. Some of the onboard shops were wired up with a closed-circuit tv network, whereby the shop could request a central blueprint librarian retrieve a particular drawing and project it onto the monitor. Essentially a stone age LAN (local area network), this setup was not as successful as hoped.
(Although it would be anchored for its core mission, USNS Corpus Christi Bay still had to be capable of open seas navigation. This is the post-refit bridge.)
On 12 January 1966 all conversion and work-up efforts were completed and USNS Corpus Christi Bay was ready for use in the Vietnam War.
(The converted ship relighting boilers in drydock.) (photo from All Hands, the US Navy’s magazine)
(Following the Civil War, the US Navy instituted the Board Of Inspection & Survey, or INSURV, for all military vessels. This is an ultra-rigorous inspection done every five years or when a ship recommissions. The above photo shows USNS Corpus Christi Bay’s INSURV team comparing FAMF specifications with the stack of shipyard work receipts. The ship passed its INSURV.)
(USNS Corpus Christi Bay passes under US Highway 181 during sea trials after the conversion.)
During the post-conversion sea trials, it was found that the ship was excessively topheavy. This is not hard to believe, just by looking at the huge new aft section which was high above the centre-of-gravity. Several tons of concrete ballast were poured into the bilges to rectify this.
(Pleasure boats pass USNS Corpus Christi Bay in its namesake body of water. The ship visited Texas to onload spare helicopter parts prior to sailing for Vietnam.)
(At sea during the post-conversion workup.)
the Vietnam War
USNS Corpus Christi Bay departed for South Vietnam in 1966. Aboard were 308 US Army soldiers of the 1st Transportation Battalion – Aircraft Maintenance (Seaborne).
The initial Army contingent was almost all volunteers specifically for this mission, and over a third were career soldiers with at least 10 years in uniform already. Some were sent to a special high-intensity training program at Ft. Benning, GA while the ship was conducting sea trials.
Per legislation at that time, as a MSC ship USNS Corpus Christi Bay itself mounted no weapons but the US Army contingent aboard was not restricted by this and had M14 rifles and M1911 sidearms.
The ship was also fitted for carriage of one “J-boat”, one of a US Army series of motorboats varying in details. During the Vietnam War they were used as inport patrol boats. For USNS Corpus Christ Bay, the ship was usually anchored far enough offshore in Vietnam that Viet Cong swimmers were not really a concern and the J-boat was infrequently used in its intended role.
(The J-boat is visible here alongside the starboard crane by the small freight elevator. The huge hatch on the flight deck is also visible. This photo also shows the big periodic log HF radio antenna from above.)
USNS Corpus Christi Bay arrived at Cam Ranh Bay on 2 April 1966. The ship was nominally under the 34th Aviation Support Group at Tan Son Nhut AFB but was basically its own thing.
(USNS Corpus Christi Bay in Cam Ranh Bay in 1966.)
Contrary to what one might imagine, the least desirable repair route was flying whole helicopters onto the ship. Instead it was preferable to extract components or sub-components at bases ashore, and then transport them aboard. The most expeditious method was using helicopter shuttles; but more common was to bring them out by an amtruc (wheeled 15-ton amphibious truck) or a “mike boat” (converted WWII landing craft). Often a spacing barge was tied alongside USNS Corpus Christi Bay, to which the amtruc or boat moored so the crane operator had better visibility.
(CH-47 Chinook delivering helicopter components needing repair.)
(Taken during 1966, this photo shows a UH-1 Iroquois of the 101st Airborne unloading items needing repair. The stand-up forklift could make tighter turns aboard ship than a 4-wheeled forklift.)
(USNS Corpus Christi Bay with a barge moored alongside.)
The ship did occasionally tie up in South Vietnamese ports, but this was done sparingly. It did expose the ship to increased danger, while offering no real benefit to bringing things aboard.
(USNS Corpus Christi Bay pierside at Ða Nang with a Huey leaving the “admin pad”.)
About a dozen of the US Army contingent were “sand crabs” assigned and barracked ashore. Especially at Vung Tao, this was useful for pre-staging helicopter components to be repaired so they were sent to the ship in the most beneficial order. The US Army installed a AN/TRC-24 system aboard USNS Corpus Christi Bay while it was in-country. This allowed the ship a short-range 12-channel FM voice link with US Army bases ashore.
(Aviation components being serviced aboard USNS Corpus Christi Bay.)
The skill level and creativity aboard were so great that USNS Corpus Christi Bay branched out from repairs and developed and manufactured “on the spot” flash suppressors for machine guns aboard US Army helicopters, and a type of skid shoe for OH-6 Osage helicopters.
In late 1969, the US Army detachment aboard was stunned to receive an order from the Army Audit Agency recalling USNS Corpus Christi Bay to the United States. The vague reasoning was that during the 1967 fiscal year, the ship had supposedly failed to attain a Pentagon “goalpost” of parts repaired. The ship remained in use in South Vietnam while the recall was vehemently appealed against. It was eventually rescinded. Even today it is difficult to imagine what the AAA was possibly thinking wanting to pull such a valuable asset out of the war.
Despite some problems (for example the air conditioning system was never great to begin with and eventually failed altogether) USNS Corpus Christi Bay continued to excel at its mission. Productivity peaked in late 1969 and early 1970, when USNS Corpus Christi Bay repaired, on average, about $3.76 million worth of helicopter parts every month.
(USNS Corpus Christi Bay off of Vung Tau.)
Although the ship’s work never slowed, President Nixon’s efforts to shift more of the war’s burden onto South Vietnam coincided with a change in the nature of US Army helicopter repair needs. American helicopters obviously still needed upkeep, but by 1971 battle-damaged helicopters were declining – this being, they seemed to either be shot down completely or took damage which could be repaired at local forward bases. For example by the end of the year, there was actually a slight surplus of entire Lycoming T53 engines ashore in South Vietnam. Hueys with a broken-down or damaged engine just had the whole thing swapped out instead of a part repaired.
In 1972, the US Army decided that the ship’s mission was at its end. USNS Corpus Christi Bay departed South Vietnam having spent over 6½ years in theatre. On 19 December 1972, USNS Corpus Christi Bay moored at Corpus Christi, TX.
From a tactical military standpoint the FAMF concept was an overwhelming success. There is simply no question to that. On average, 5,000 airframe flight availability-days per year were saved.
From a budgetary standpoint, it was also a success in that by the sixth year in theatre, the cost to convert the ex-USS Albemarle had been recouped in terms of the freight costs avoided and the opportunity costs of using that sealift bandwidth for other needs.
a second FAMF
As it was quickly clear that the FAMF concept was valid, the “Flat-Top” office sought a second such ship. The most natural choice was USS Albemarle‘s only WWII sister-ship USS Curtis (AV-4). It had been fitted with an “admin pad” during the 1950s for use in Antarctica, and had decommissioned in 1957.
(The mothballed USS Curtis.)
The US Navy had transferred the ex-USS Curtis‘s title to the Maritime Administration in July 1963, as it (similarly to the ex-USS Albemarle) had no foreseen further usefulness. The “Flat-Top” team found it to have degraded physically much more than anticipated and the reactivation costs would have been prohibitive.
In 1968, the ex-USS Salisbury Sound (AV-13) was instead selected as the next prospective FAMF. This WWII seaplane tender was of the Currituck class which followed the Curtis class, and similar enough that most of the development work of USNS Corpus Christi Bay could be recycled. USS Salisbury Sound had just decommissioned in March 1967.
However in 1969, Army Materiel Command was restructured, and “Flat-Top” was no longer a directly-reporting project management office. This did not eliminate it, but it pushed it down the totem pole in terms of influence. Later that year the US Army stated that no further FAMF funding would be allocated. USNS Corpus Christi Bay would be a one-off.
operation “Hula Hoop-73”
This was the final deployment of USNS Corpus Christi Bay. Along with USNS Wheeling (T-AGM-8), the ship monitored French nuclear tests at the Tuamoto Islands in the south Pacific during 1973. The US Army detachment was not embarked, the ship was simply an available hull.
“Hula Hoop” was actually a series of operations over several years, whenever the French were about to test a nuclear weapon. They typically detonated five or six a year in the 1970s. For the seaborne monitoring part, US Navy ships were free to operate anywhere outside France’s 12 NM limit around the test atoll.
Supposedly a random operational code name, “Hula Hoop” might have referenced the constant orbits the USAF monitoring aircraft flew around the islands.
(Left: NC-135 “Burning Light” nuclear monitoring planes were plastered with scientific blisters, nacelles, pods, and camera ports; and were one of the most difficult types in the 1970s US Air Force to fly. They were based at Kirtland AFB, NM but deployed to Hickam AFB, HI in 1973. Right: A French tactical nuclear weapon detonating over Mururoa Atoll in 1973. Typically loose warheads were suspended from a balloon but occasionally whole missiles or bombs were tested.)
end of the road
There was naturally a desire inside the US Army to retain this useful asset for any future need. However inbetween departing South Vietnam and returning from “Hula Hoop”, USNS Corpus Christi Bay rode out a hurricane which caused internal structural damage. The damage was not severe enough to put the ship in peril, but it was of the nature that if left uncorrected, would worsen steadily with time.
None the less there was a proposal in late 1973 to keep the ship in lay-up at Corpus Christi, TX. However in 1974, with America’s involvement in Vietnam ended and the military facing big budget cuts, this was rejected. The “Flat-Top” office was terminated that same year.
At 23:59 on 31 December 1974, USNS Corpus Christi Bay was removed from the MSC active status rolls. On 8 January 1975 the ship was towed to the Maritime Administration’s Beaumont, TX anchorage where it was stripped of equipment useful for other mothballed WWII warships. In July 1975, the hulk was sold to Brownsville Steel & Salvage. It was towed down the Texas coast and scrapped that year.
(The government’s receipt for the sale of the ship in 1975.)
(A model of the ship unveiled at Corpus Christi Army Depot during the summer of 2018.) (photo via KZTV)
The USA has fought three major land wars since the Vietnam conflict, but there has not been an asset quite like this since. During Desert Storm, US Army helicopters used more advanced ashore facilities in Saudi Arabia combined with a robust airlift effort of helicopter parts. Afghanistan is landlocked so the idea was irrelevant to that war. During the Iraq War, a system similar to Desert Storm was used.
USNS Corpus Christi Bay remains a unique item of the Vietnam War, and a success in its mission.