D-Day: The conundrum of supplying fuel
to the Allied liberators

The Allied invasion of Nazi-occupied Europe on D-Day was the largest amphibious landing operation in history.

Soldiers going ashore
at Normandy

6 June 1944 was the date on which a massive Allied military, air and naval force began the long-awaited invasion and liberation of Nazi-occupied Europe.

Although the Allies had launched a bombing campaign against Germany and had reached Italy, the only way to defeat Germany was to cross the English Channel to liberate the occupied countries and invade Germany itself.

Allied forces were drawn mainly from Great Britain, Canada and the United States. Others came from Australia, Belgium, Czechoslovakia, France, Greece, the Netherlands, New Zealand, Norway and Poland.

The raw figures are astonishing:

  • 156,000 troops or paratroopers were put ashore; 73,000 from the US, 83,000 from Great Britain and Canada. Around 3,000 were from Australia which was engaged in fighting the Japanese closer to home territory at the same time. Australia’s main contribution was in the air. Between 2,000 and 2,500 Australian airmen served in dozens of RAF and 10 RAAF squadrons.
  • 195,700 naval personnel were used in Operation Neptune, led by 53,000 U.S. and 113,000 British troops.
  • By the end of June 11, 326,547 troops, 54,186 vehicles and 104,428 tons of supplies had been put ashore.
  • 11,590 Allied aircraft flew 14,674 sorties on D-Day. Of those, 127 planes were lost. Some 2,395 aircraft and 867 gliders took part in the airborne assault.
  • 6,939 vessels were in the fleet: 1,213 combat ships; 4,126 landing ships/craft; 736 support ships; 864 merchant ships.

The number of casualties was similarly astounding; a high price was paid to eventually put an end to German aggression in Europe, beginning on D-Day.

Casualties refers to all losses: killed, wounded, missing in action and prisoners of war. An accurate casualty count may never be known but research by the US National D-Day Memorial Foundation produced these figures:

  • US casualties on D-Day: 2,499 dead, 3,184 wounded, 1,928 missing, 26 captured.
  • Other Allied casualties on D-Day: approximately 2,700 British, 946 Canadians. (Fourteen Australians were killed on D-Day – two RAN and 12 RAAF).
  • German casualties: 4,000-9,000.
  • Total killed, wounded or missing in the Battle of Normandy (June 6-25) for both sides: 425,000.
  • French civilians killed in Normandy: 15,000-20,000, mainly from Allied bombing.
  • Today, 27 cemeteries hold the remains of more than 110,000 dead, including 9,386 Americans, 17,769 British, 5,002 Canadians, 650 Poles, and tens of thousands of Germans.

Logistics nightmare

The massive supply operation at Omaha Beach
during the Allied invasion at Normandy.

Supplying the front lines of the liberating force after the invasion was a logistics nightmare. Taking vital goods – particularly fuel – across the English Channel was fraught with danger. German bombers could swoop at any time with catastrophic results. Conventional tankers and ship-to-shore lines were not the answer.

The havoc that could be wreaked by German planes was in the mind of the planners. A touch of genius was required.

British engineers had just such an inspiration: Lay a pipeline under the water across the English Channel.

“Operation PLUTO” – Pipe Line Under The Ocean – or probably more correctly, Pipe-Line Underwater Transport of Oil – was the chosen strategy.

Although by 1942 the oil industry had laid thousands of pipe miles of across terrain, crossing the Channel to support Operation Overlord (the sea portion was called Operation Neptune) needed a previously unimaginable level of technology.

The scheme was developed by Arthur Hartley, chief engineer with the Anglo-Iranian Oil Company.

To get vital oil supplies across the Channel after the D-Day landings, pipelines were unwound from massive spools to connect pumping stations to French ports.

Hartley proposed using modified submarine telephone cable. The plan got the seal of approval in 1942 from Geoffrey William Lloyd, the Minister for Petroleum, and Admiral Mountbatten, Chief of Combined Operations and then chairman of the Anglo-Iranian oil company.

There were actually two proposals.

In the first, a three-inch flexible lead pipe would be used to cross almost 70 mi (112 km) from the Isle of Wight to Cherbourg (more than 46 tons of lead, steel tape and armored wire were required for each mile). They were known as HAIS pipes.

These cables were a development of existing underwater communications cables by Siemens Brothers, in conjunction with the National Physical Laboratory (NPL),

A cross-section of the lead pipe

The first pipeline from Isle of Wight to Cherbourg was laid on 14 August 1944. No existing communications cable laying ship could do the job and a civilian passenger vessel, London, was the first to be modified to accommodate a huge spool around which the new pipe would be coiled.

In the second plan, three-inch (7.6 cm) steel pipe, which had proven to be flexible and durable in the oilfields of Iraq and Burma, would be used. Welders assembled 20-foot (6 m) sections of steel pipe into 4,000-foot (1219 m) lengths. They were known as HAMEL pipes.

The second approach proved more successful.

The pipeline was wound on to huge floating “conundrums” (Cone-ended drum) that looked like giant cotton reels and were designed to spool the pipes off the drum when towed. Five conundrums were commissioned – they were 30 feet (9 m) in diameter and fabricated in Scunthorpe, erected in Tilbury Docks and launched into the Thames. Each weighed 250 tons and had a combined capacity to carry up to 60 nautical miles of HAMEL pipes.

A "conundrum" is made ready

The deployment systems each weighed 1,600 tons and were pulled by three tugboats from the British site at Dungeness to the French port of Boulogne, 31 miles (50 km) away. As the spools unwound, the pipe settled to the bottom of the English Channel.

Ultimately, using both methods, 17 pipelines were put in place to supply thousands of litres of fuel to Boulogne. Dumbo was the codename given to the pipeline that ran across Romney Marsh to Dungeness and then across the English Channel to France.

By the time the two HAIS flexible pipelines and the two HAMEL steel pipelines to Cherbourg were pumping petrol, the Allied armies were moving west towards Paris and Belgium. Eleven new HAIS pipelines and 5 HAMEL pipelines were laid in a swept channel 2 mi (3.2 km) wide between Dungeness and Ambleteuse near Boulogne to shorten the route.

Map: Ashley T. Walker for the Library of Congress

The initial performance of the PLUTO pipelines was disappointing and didn’t immediately contribute much to the Allies’ advances. During the period from June to October 1944, PLUTO carried on average only 150 barrels per day, just 0.16% of the Allies’ total daily consumption.

In January 1945, 305 tonnes (300 long tons) of fuel was pumped to France per day, which increased to 3,048 tonnes (3,000 long tons) per day in March, and eventually to 4,000 tons (almost 1,000,000 Imperial gallons) per day. In total, over 172 million imperial gallons of petrol had been pumped to the Allied forces in Europe by VE-day (Victory in Europe Day, 8 May 1945), providing a critical supply of fuel until a more permanent arrangement was made.

A total of 34 vessels with 600 men and officers were involved in the pipeline operation.

Another important aspect of the system was the protection of the pumping stations on land. Camouflage was the answer.

All installations in British were disguised to prevent the Germans identifying them as part of the fuel operation. Terminals and pumping stations in Dungeness and Greatstone were disguised as bungalows, gravel pits, garages, a golf club and even an ice cream shop.

How the pumphouses were disguised

A house on the south coast of England, requisitioned by the British Army, and used to house pumping equipment

Some new buildings were erected, but 27 existing seaside bungalows and houses on Dungeness and Greatstone were used.

In England, the PLUTO pipelines were supplied by a 990 miles (1,600 km) network of pipelines to transport fuel from ports including Liverpool and Bristol. In Europe, the pipelines were extended as the troops moved forward, and eventually reached as far as the Rhine.

After the war, the lines were decommissioned and many salvaged for their lead.

Sir Winston Churchill at the unveiling of the plaque to commemorate the laying of the PLUTO pipelines described it as being “crowned by complete success”.

The pipelines were the forerunners of all flexible pipes used in the development of offshore oil fields.

Sources: Various web sites dedicated to D-Day history.

Book: PLUTO: Pipe-Line Under the Ocean by Adrian Searle




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