At the end of World War I, US naval planners assessed the naval operations of that conflict and came to the conclusion that a fleet lost 10% of its combat capability for every 1,000 miles (1600 km) it operated away from its base. The implications of this assessment were then compounded by the fortifications clause of the Washington Naval Treaty of February 1922 and expressly forbade the further development of British, Japanese and US bases in the western Pacific. This compelled the US Navy to study the problem of creating a major fleet supply train to allow the Pacific Fleet to project US power far from its permanent bases. This paved the way to innovations in the design of floating dry docks and in the equipment and practices of underway replenishment, as well as prompting the US Navy to create a Service Force as a supply train. Although the number of auxiliary vessels need by the Service Force was very tightly limited in the period between the wars, when budgetary limitations inevitably meant that funding was allocated to warship construction rather than auxiliaries, the US Navy nonetheless gained a significant understanding of what would be required in war and how such a fleet train could be created and mobilised to provide the US Navy’s warships with the ability to operate independently of shore bases and over great ranges and extended periods.

In the first year of the USA’s involvement in World War II from 7 December 1941, the numbers of support vessels available in Admiral Chester W. Nimitz’s Central Pacific Area increased very rapidly from an initial 77 to 358 in December 1942. This made feasible one of the most essential US Navy innovations of the war, the At Sea Logistics Service Group. This began with the reorganisation of Service Squadron 4 at Funafuti atoll in the Ellice islands group as the first floating supply base.

Large rear-area forces

The At Sea Logistics Service Group rapidly developed into the core of the Pacific Fleet’s logistics tail, and by October 1944 it was a full-scale and full-capability floating naval base comprising 34 oilers, 11 escort carriers, 19 destroyers, 26 destroyer escorts, and several fleet tugs. These were grouped into as many as 12 replenishment task units for continuous at-sea rotation, with three or four such units (with between nine and 12 oilers) constituting a replenishment task group. This operated just out of the maximum radius of Japanese land-based warplanes, and each replenishment task unit was relieved by another every few days during active operations, the relieved task unit then steamed to Ulithi atoll in the Caroline islands group to replenish from merchant tankers. Each replenishment task unit also included one escort carrier to deliver replacement aircraft and pilots to forward units, and all were escorted by other escort carriers and destroyers. Tugs were assigned to each replenishment task unit and could be sent into the combat zone to tow crippled warships out of danger.

The US Navy’s underway replenishment capability in the Pacific campaign reached an early apogee with Rear Admiral Donald B. Beary’s Service Squadron 6 which, in the course of the ‘Detachment’ campaign to take Iwo Jima, delivered about 370,000 tons of fuel oil, about 14,000 tons of Diesel oil and 7,126,000 US gal (26970000 litres) of aviation fuel. Over the same period, Service Squadron 4 operated as a complete floating naval base with a complement of tenders, repair ships and concrete barges.

Some shortages

The most serious shortage was that of provisions storeships, which could not always bring forward enough fresh and frozen food for the fighting fleet, and on these occasions dry provisions such as beans and tinned meat had to be substituted for fresh food. Munitions ships were also in short supply, and had to be supplemented with ‘Victory’ ships converted as auxiliary munitions ships. An idea of US Pacific Fleet’s fleet train extraordinary capabilities is indicated by its supply deliveries in the course of the ‘Iceberg’ campaign to take Okinawa: 10.133 million barrels of fuel oil, 323.000 barrels of Diesel oil, 25.573 million US gal (96.804 litres) of aviation fuel, 16,375 tons of bombs and ammunition, 998 replacement aircraft, 220 replacement aircrew, 2,219 tons of refrigerated food, 4,005 tons of dry food, 575 tons of ship’s stores, 15,398 bags of mail, 1,240 passengers and 1,032 replacement personnel.


By the time of the ‘Iceberg’ campaign, the US Navy now had surplus capacity for the delivery of dry provisions, as exemplified by the fact that one such ship remained anchored in Ulithi atoll between 25 February and 13 June 1945 before a use could be found for its dry cargo. This surplus capacity was the result of the fact that the earlier shortage of provisions storeships had finally been rectified, and that ships in combat areas preferred fresh to dry provisions. It should be added, though, that about 100 ships were sunk by kamikaze attack or sent back to the west coast of the continental USA for repairs during the Okinawa campaign, and therefore had no need for supply by the fleet train.


An unintended result of the fleet train system’s efficiency was that it prove more efficient to deliver fresh supplies from west coast ports than to bring supplies forward from rear bases left in the wake of the US forces’ very rapid advances later in the Pacific War.


The Japanese conquest of Timor (II)

September 19, 2016

Switch to guerrilla tactics By the end of February, the Japanese were in control of most of Dutch Timor and the area round Dili in the north-east. The Australians remained in the island’s south and east, however. The 2/2nd Independent Company was trained for stay-behind operations and had its own engineers and signallers, although it […]

Read the full article →

The Japanese conquest of Timor (I)

September 12, 2016

The Battle of Timor resulted in the Japanese seizure of the island of Timor, on which the colonial powers were the Netherlands and Portugal, to the north-west of Darwin in the Australian Northern Territory. The Japanese invaded the island on 20 February 1942 and were resisted by a small Allied force. This Sparrow Force comprised […]

Read the full article →

The Japanese conquest of Hong Kong

August 25, 2016

At the beginning of World War II, Hong Kong was a British possession on the south-west coast of China to the south-east of Canton in the Pearl River estuary. The Chinese had ceded Victoria island to the UK at the end of the 1st Opium War (1839/42), and the New Territories on the mainland were […]

Read the full article →

Japan’s greatest Pacific base – Truk atoll

August 1, 2016

The US geographical (rather than operational) codename for Truk atoll in the Caroline islands group of the central Pacific between 1941 and 1945 was originally ‘Anaconda’ and then ‘Panhandle’. A group of hilly islands, the tips of drowned mountain peaks, surrounded by a large barrier reef with five passes, Truk is a large atoll lying […]

Read the full article →

‘Fathead’ – A Far-Eastern ‘Mincemeat’?

July 11, 2016

The head of ‘GSI(d)’, one of the the British organisations responsible for deception activities in the Far East in World War II and which was merged in January 1944 with the Special Planning Section to create the ‘D’ Division, was Peter Fleming, a well known writer and brother of Ian Fleming, the creator of James […]

Read the full article →

A successful British deception of WWII – the ‘Cyprus Defence Plan’

July 4, 2016

The ‘Cyprus Defence Plan’ was a pioneering and very effective British deception plan, created in the aftermath of the German seizure of Crete in ‘Merkur’. The plan suggested that Cyprus, which could have been Germany’s next target for airborne assault and would offer the Axis powers considerable strategic advantages, was held by forces considerably stronger […]

Read the full article →

Operation ‘Tabarin’ – a far flung British undertaking of World War II

June 6, 2016

In 1938/39 Germany undertook its third Antarctic expedition. Led by Kapitän Alfred Ritscher of the German Navy, the expedition was to find part of Antarctica on which a German whaling station could be established as a way to increase Germany’s production of fat. Whale oil was then the most important raw material for the production […]

Read the full article →

Operation ‘Longshanks’

May 30, 2016

Operation ‘Longshanks’, which was otherwise known as ‘Boarding Party’ and ‘Creek’, was a peculiar British operation against a German merchant ship moored, as a neutral, in the Portuguese enclave of Goa in western India, and took place on 9 March 1943. The operation was undertaken by members of the Calcutta Light Horse, a reserve unit […]

Read the full article →

Operation ‘Postmaster’

May 23, 2016

Occurring on 13 January 1942, this was a British seizure of Axis shipping in Santa Isabel harbour on the neutral Spanish island of Fernando Pó (now Bioko in Equatorial Guinea) in the Gulf of Guinea off the west coast of Africa. The operation was undertaken by the Special Operations Executive’s ‘Maid Honor’ Force, so-named for […]

Read the full article →