World War II and PLUTO: The Pipeline under the Ocean
By Dr. Brian Blodgett
Faculty Member, Homeland Security, American Military University
After the D-Day landings at Normandy and the initial breakthrough of the Nazi-held Western Front, the Allies found themselves needing a significant amount of fuel for their growing number of military vehicles. Without this influx of fuel oil, the Allies’ advances could slow and even grind to a halt. That would potentially allow the Germans to regroup and counter-attack.
Allied planners quickly ruled out the use of conventional oil tankers with “ship to shore” pipelines. Oil tankers would not only clutter the beaches and obstruct the movement of men, weapons, and materials, they would also be easy targets for the German Luftwaffe.
Two years earlier, in early 1942, Geoffrey Lloyd, chief of the UK’s fuel policy, met with Lord Mountbatten, the head of Britain’s Combined Operations, and others. They conceived of the idea of connecting the existing thousands of miles of British pipelines to new pipelines that would rest on the bottom of the English Channel and emerge on the European mainland. However, the devil was in the details.
Operation PLUTO Required a New Type of Pipeline
Operation PLUTO, (Pipe-Lines Under the Ocean) required the Allies to construct a new type of pipeline that could span the English Channel. The plan also required disguising fuel depots and pumping stations along the English south coast from German attacks.
With great secrecy, existing bungalows, garages and other innocuous-looking buildings along the south coast of England were converted into oil terminals and pumping stations from England’s oil storage and port facilities around Bristol and Liverpool.
The underwater pipelines, however, created a much bigger challenge. Knowing that there would be a need for tens of thousands of gallons of fuel to transit those pipelines, PLUTO became the lifeblood of the Normandy invasion.
Preliminary Pipe Was Based on Submarine Cable Technology
The preliminary pipe design was based on existing submarine cable technology. It involved a three-inch bore pipe of hardened lead surrounded by two layers of prepared paper tape, one layer of bitumen prepared cotton tape, four layers of mild steel tape, jute bedding, steel armored wires and an outermost layer of jute servings reinforced with galvanized steel wire. Tests proved the pipe could hold the necessary 600 pounds per square inch (psi) of pressure and much more.
In June, a deep-water trial was completed successfully on the Clyde estuary. The test also demonstrated the need for an internal pressure of 100 psi at all times, from manufacture to laying the pipe to prevent cable distortion or collapse. Another discovery was that existing cable-laying ships were not large enough nor was the loading and pipe-laying gear powerful enough. So several merchant ships were converted for pipe-laying duties.
Each mile of pipe required 24 tons of lead, 7.5 tons of steel tape, and 15 tons of steel armored wire and smaller amounts of other materials. Due to a potential shortage of lead, the Allies produced a steel pipe that was cheaper than lead but more fragile.
The final diameter of the pipe was four and a half inches and weighed over 47 tons empty. To keep the pipe from developing kinks, twists and collapse, the pipe was filled with pressurized water, which increased the weight of the pipeline to over 54 tons. One coil of pipe, which was normally between 30 and 50 miles long, weighed between 2,500 and 4,000 tons.
The pipes were only part of the requirements; the most critical component was the need for leak-free joints to link the pipes. It took over two years, working 18 hours a day, to manufacture the needed 1,300 one-inch joints.
Laying the Pipe
The modified ships were able to carry a huge spool of coiled lead pipe. As they crossed the Channel, the pipe uncoiled and sank to the bottom. For the more fragile steel pipe, large floating spools were towed behind a group of three tugboats.
Two PLUTO routes of pipelines connected England to the European mainland. DUMBO’s 30 miles of pipe ran across the Strait of Dover from Dungeness, England, to Ambleteuse, France. A second route, known as BAMBI, consisted of 70 miles of pipe running from the Isle of Wright to Cherbourg, France. “In total, 500 miles of pipeline connected the French coast across the Channel to England, and along the overland pipeline to oil terminals near Liverpool.”
By March of 1945, one million gallons of fuel passed through the pipes each day. By the end of the war, an estimated 172 million gallons of fuel oil had crossed the English Channel undetected by the Germans due to the Allies’ deception plans and their aerial domination of the Western front. After the war, British Prime Minister Winston Churchill declared, “Operation PLUTO is a wholly British achievement and a piece of amphibious engineering skills of which we may be proud.”
About the Author
Dr. Brian Blodgett is an alumnus of American Military University who graduated in 2000 with a master’s of arts in military studies and a concentration in land warfare. He retired from the U.S. Army in 2006 as a Chief Warrant Officer after serving over 20 years, first as an infantryman and then as an intelligence analyst. He is a 2003 graduate of the Joint Military Intelligence College where he earned a master of science in strategic intelligence with a concentration in South Asia. He graduated from Northcentral University in 2008, earning a doctorate in philosophy in business administration with a specialization in homeland security.
Dr. Blodgett has been a part-time faculty member, a full-time faculty member and a program director. He is currently a full-time faculty member in the School of Security and Global Studies and teaches homeland security and security management courses.