Saying 'Thanks' to Operation PLUTO

Unreeling pipelines across the English Channel after D-Day gave Allied forces a leg up in fueling final European victory in World War II, but also fostered an essential element of today's deepwater offshore petroleum technology.

Current development of deepwater oil and gas, particularly in the Gulf of Mexico, simply couldn't be accomplished without reeled pipe.

Granted, the industry couldn't do without any of the technologies developed relatively recently for deepwater petroleum operations. But reeled gathering lines and the equipment needed to lay them onto the ocean floor in thousands of feet of water, then linking them with subsea wells, risers, and so forth, are as essential to today's offshore business as the seafloor equipment itself, and reeled pipe applications have grown significantly in scope during the past decade or so.

But for the initial development of reeled pipelines, the industry can thank a little known aspect of the Allied invasion of occupied Europe in June 1944, nearly 61 years ago.

Operation PLUTO (Pipe Lines Under the Ocean) was a wartime British project--first addressed in 1942--to bring motor fuel from Britain 70 miles across the English Channel to two French channel ports. From there, the fuel would go to battleground refill points to keep thirsty war vehicles running as Allied armies pushed into occupied territory.

Historians hold that the late Louis Mountbatten set PLUTO in motion. Mountbatten (later knighted 1st Lord Mountbatten of Burma) was the dashing great-grandson of Britain's Queen Victoria and uncle of Queen Elizabeth II's husband, Prince Philip. A Royal Navy hero who later went on to hold the dubious distinction of being India's last Viceroy, he held several major posts in Britain's armed forces during the war with both Germany and Japan. During the two years leading up to the Normandy invasion, he was Chief of Combined Operations for Allied forces in Europe and was in on setting up invasion-related strategic initiatives

Briefly, when planning the invasion two years before it actually occurred, Allied commanders knew that supplying fuel by sea to invasion forces would be dicey, at best, because at the time there was the potential threat that German aircraft, naval surface vessels, and U-boats could cause major interruptions in cross-channel tanker traffic. Such raids would threaten to cut off or severely interrupt supplies of gasoline and diesel fuel, the life's blood of the invaders' overland transport of war material and fighting men. Besides, they noted, invasion-related bombing and battle damage to French ports would delay offloading from any ocean shipping. It probably would take weeks, even months, to clear the ports for such traffic.

On the other hand, it also was true that fueling trucks and armored vehicles from hand-held, 4-gallon cans unloaded from amphibious vessels on the beach was no more positive an alternative, particularly as forces pushed farther inland.

The most effective way to get fuel to France, they surmised, would be by pipeline.

Building small-diameter underwater pipelines was not a brand-new technology at the time. The petroleum industry had been doing so since the early 20th century to bring oil and gas to shore from over-water wells drilled in Caddo Lake on the Texas-Louisiana border, in Lake Erie, and in Venezuela's Lake Maracaibo, among other areas. What's more, producers had been installing pipelines across bays and inland lakes along the U.S. Gulf Coast since the late 1930s.

But by 1942, the technology of laying underwater pipelines was limited generally to two modes:

  • Assembling the pipeline onshore, joint by joint, and then floating or dragging it into the water in sections, adding pipe as the line snaked farther out from shore.
  • Assembling the entire line over water, and then laying it down to the seafloor progressively--and carefully--as each length of pipe was welded to the end.

  • Either way was fine for protected waters. But frequent, year-round gales in the North Sea area often churn the English Channel into a maelstrom of heavy winds, waves, and dangerous currents. And even in the calmest of seas, the physical and technical problems associated with floating out or building sections of pipeline on the surface across 70 miles of water would be unprecedented. Lowering the line safely to the sea bottom, which sloped to water depths of 250 ft or more at its mid-point, would call for a large number of support vessels and offshore workers, and also would be restricted to near-calm weather conditions. One kink or break in the line would cause serious delays in the pipe laying progress. Worse still, besides taking a lot of time to complete, neither method could even be applied until the Allies had a firm foothold at least a few miles beyond the beach head, and when that might occur was anyone's guess.

    However, the ultimate solution to such challenges came not from military logisticians but from petroleum industry engineers.

    According to most accounts, Mountbatten, considering the issue, picked up an idea put forth by A.C. Hartley, chief engineer for Anglo-Iranian Petroleum Corp. (a predecessor of BP) to lay a cross-channel line that could be unreeled, in a near-continuous fashion, onto the ocean floor.

    Under Hartley's direction, the company's pipeline specialists--who were helping build a 1,000-mile onshore products pipeline in Britain at the time--suggested using submarine cable technology, minus the core, as the basis for the channel line. In essence, the line pipe could be manufactured in several very long lengths, wound around reels, and then deployed rapidly off the back of a ship much the same way submarine power and telephone cables had been installed for nearly a century.

    With the help of fellow engineers from Burmah Oil Co. and Iraq Oil Co. and using the facilities and know-how of normally competitive cable and pipe manufacturers, the PLUTO group eventually developed two types of pipe for the job.

    Siemens, a UK-based cable manufacturer, developed one form--made of lead pipe swathed in insulation, reinforced by steel wire, and coated in tar and yarn. Because it was made chiefly of lead, the line could be reeled and unreeled easily enough without damage.

    At the same time, mainly because there was some doubt as to the wartime availability of lead in large enough quantities, oil company engineers proved, through testing, that regular 3-inch-diameter steel pipe, similarly coated and protected, could be wound around large reels without breaking and--using extreme care and a "straightening" device--could be unreeled to the channel floor in much the same way.

    So, cable and pipe manufacturers in the UK and in the U.S. started producing the pipe needed for what would be multiple product lines. By the eve of the invasion, in mid-1944, the pipe was waiting in southern English ports, wound onto huge reels mounted on specially converted vessels. Operation PLUTO was ready to roll, with lines to be laid from the mainland to the Isle of Wight and then cross-channel to Cherbourg, and from Dungeness in Scotland straight across to Boulogne.

    The start of reeled line deployment was delayed by about a month after D-Day, June 6, 1944, due mainly to delays in capturing Cherbourg and minesweeping operations in the channel. However, after another month or two, the Allies had laid 17 such pipelines of both types across the channel. A total of 34 vessels were employed, manned by 600 men and officers. Once making landfall in France, the reeled lines were connected to onshore distribution systems built progressively as the battle fronts advanced into enemy territory, following behind Allied forces as they pounded German forces back toward their homeland.

    Once fully operational, the PLUTO lines, totaling some 710 nautical miles in combined length, carried 1,350,000 UK gallons (about 37,500 UK barrels) of fuels daily through the two French ports and on into the front-line distribution network. By the May 1945 end of the war in Europe, the lines had carried a combined total of about 172 million gallons (4.7 million barrels) of fuel to fighting forces.

    Pumping continued through July 1945. In the ensuing years, much of the onshore distribution network was removed. In some areas, they removed it much to the consternation of local residents, who had devised ways to tap line sections that still held liquids and thus fueled their personal and work vehicles for free.

    While today's deepwater reeled pipe operations involve much more sophisticated technology, including exotic steel pipe alloys, various pipe-in-pipe configurations and wrappings to promote essential insulation from cold temperatures and high pressures, and seafloor hookups using unmanned submersibles, the "sea dogs" of today's petroleum industry must nevertheless tip their hard hats in gratitude to the doggedness of the people who planned and accomplished Operation PLUTO.