Pluto: a Virtual Modelling Project; Introduction The subject of my modelling activities has recently centred on the 1944 Allied invasion of Continental Europe in operation Overlord, and during the research into the preparations for D-Day there was a one line sentence in a publication which caught my attention. This referred to the transportation of the PLUTO pipeline by the railway through Southampton docks. The interesting part was the statement that the pipeline, all 72 miles of it, was carried in one whole on a train of several wagons, and is written in ‘Facts about British Railways 1943’ publication issued by the British Railways Press Office. The sentence is reproduced here: DOCKS: One shipment of special interest which has passed through railway docks consisted of a submarine cable 72 miles long, entirely in one piece. For conveyance by rail to the ship's side ten tube wagons were used. The idea that a huge length of oil pipe could be carried on a train of wagons was so unusual that it became the subject of my next railway modelling project and I set about researching the PLUTO project. From the PRO records this project was known as the Pipeline Underwater Transport of Oil, but is also more commonly known as Pipe Line Under The Ocean. Background The reliable supply of petrol for the advancing Allied forces following the D-Day landings was of the highest priority. Planners knew that the future invasion of Europe would be the largest amphibious landing in history and without adequate and reliable supplies of petrol any advance would at best slow down and at worst grind to a halt. A loss of momentum could jeopardise the whole operation as German forces would have time to regroup and counter-attack. The battle of Normandy would be won by the side who could reinforce faster with more resources. It was thought that conventional tankers and 'ship to shore' pipelines were in danger of cluttering up the beaches, obstructing the movement of men, armaments and materials. Any seaborne supply lines were subject to the vagaries of the weather and sea conditions as well as being easy targets for the Luftwaffe. It was known that oil storage facilities located near the English Channel with supplies for the invasion forces would be vulnerable to attack by the Luftwaffe. To minimise risk to the oil supply a network of pipelines was already under construction and was designed to carry fuel from safer storage and port facilities around Bristol and Liverpool to the English Channel. The idea of a pipeline under the ocean, (the English Channel), was an innovative solution and the supply network at Skanklin on the Isle of Wight and Dungeness would later be linked to the planned PLUTO pipeline. The terminals and pumping stations were heavily disguised as bungalows, gravel pits, garages and even an ice cream shop. Design And Development The Combined Operations Experimental Establishment (COXE pronounced coxy) was involved in many top-secret projects. These included such diverse tasks as waterproofing vehicles, removing underwater obstacles, testing landing craft under a variety of sea and beach conditions and to this was added the supply of petrol to France using underwater pipelines. All these challenges were borne out of a culture that encouraged bold and imaginative solutions to intractable problems - a culture which was encouraged at the highest level when Churchill ordered Roger Keyes, the then Director of Combined Operations, and his successors, to think offensively when many were at the time rightly concerned with the defence of the country. In the early part of 1942 Geoffrey Lloyd MP, who was in charge of the UK's fuel policy, met with the Mountbatten, Chief of Combined Operations (CCO) and others to consider the fuel supply issue. There was no 'of the shelf' solution that did not invite the Luftwaffe to attack shore installations or slow pipe-laying and support vessels. Lloyd approached Sir William Fraser CBE Chairman of the Anglo-Iranian Petroleum Corporation. And they picked up on an idea of Mr Hartley, the Chief Engineer of the Anglo-Iranian Oil Co., to use existing submarine cable technology, minus the core, as the basic building block of a petrol pipeline. Siemens Brothers & Co Ltd., of Woolwich, London, who were experienced in the design and manufacture of such cables, eagerly took up the challenge. It was a complex task and there were many failures arising from twists, kinks, bursts and collapse due to external water pressure and other powerful forces. The acronym HAIS was derived from the names of the designer and builders.
Early designs for the HAIS pipe were for a 2 inch bore pipe of hardened lead with 2 layers of 2 mm steel strip reinforced with galvanised steel wire. Sections were 'bench tested', a preliminary design specification was settled upon and about 1100 yards were manufactured for 'field' testing. In May 1942 HAIS pipe was laid across the Medway by the Post Office cable laying ship Alert and fuel was pumped successfully at a pressure of 600 lbs. per square inch. From observations and data collected the programme of experimentation and modification continued and by June of 1942 they were ready for deep water trials which were conducted in the Clyde estuary. These tests proved the need to pressurise the pipe during manufacture and laying operations to prevent distortion and collapse. The pipes were filled and pressurised with water for transportation. The design, manufacture and testing of couplings to join sections of the HAIS flexible pipe together also presented complex problems. The aim was to achieve leak free joints in a relatively straightforward process that was quick to complete and which did not require highly qualified engineers and sophisticated equipment. Siemen's were entrusted with the design, testing and manufacture of the couplings and the training of personnel. Each length of pipe was sealed at both ends and pressurised during the manufacturing process using 'copper bursting discs.' Within the coupling the two pipe ends were only an inch or so apart and when the full operating pressure was applied the discs burst open allowing the free flow of petrol. The final specification of the HAIS pipeline was for a flexible pipe comprising an inner lead pipe of 3" diameter, two layers of prepared paper tape, 1 layer of bitumen prepared cotton tape, 4 layers of mild steel tape, jute bedding, steel armour wires and an outermost layer of jute servings. Each mile of pipe used 24 tons of lead, 7.5 tons of steel tape and 15 tons of steel armour wire and smaller amounts of lighter materials. file:///C:/Users/IBM_AD%7E1/AppData/Local/Temp/msohtml1/01/clip_image001.jpg Diagram 1: Inland Pipe Network and Location of PLUTO pipelines. Hundreds of miles of pipeline were needed and there were concerns over the supply of lead and the time available for manufacture of the original design of HAIS. The two senior engineers (Hamick & Ellis) working on the project had experience of laying 3" steel pipelines and recalled that these were also flexible when laid in long lengths. This was welcome news and a parallel project was set up to find a second solution using steel pipes. For security reasons the two distinct systems were known as HAIS, a flexible multi layered lead based pipe and HAMEL a steel pipe. These projects took the initials of the designers and manufacturers. It was essential in war time to use terminology that would convey nothing to the enemy. As a fall back the use of the words pipe or pipeline was forbidden and all concerned were encouraged to think of cables. Both systems had to be capable of laying down their pipes on the sea-bed in a fast single procedure. The HAIS pipe would be coiled on board the cable laying vessel and fed out as the vessel progressed across the Channel and the HAMEL pipe would be coiled around huge drums towed behind a tug-like vessel and fed out as they drum rolled along.
file:///C:/Users/IBM_AD%7E1/AppData/Local/Temp/msohtml1/01/clip_image002.jpg file:///C:/Users/IBM_AD%7E1/AppData/Local/Temp/msohtml1/01/clip_image004.jpg Diagram 2: Internal Construction of PLUTO pipes. Detailed specification; lead tube internal bore 3.05 ins, minimum thickness 0.175 ins coated with petroleum residue compound, two layers of 10 mm prepared tape two ins wide, one layer of bitumen prepared cotton tape 2.25 ins wide applied with slight overlap, four layers of unvarnished cold rolled mild steel strip 2 ins wide by .022 ins thick, coating of petroleum residue compound, one serving of tarred jute yarn, 57 galvanised mild steel wires each 0.192 ins and separately compounded, coating of compound, two servings of tarred jute yarn compound between layers and overall and finally a coating of whitewash. The outside diameter was about 4.5 ins, maximum bursting pressure was 4,350 lbs/sq in, weight per mile approximately 47 tons - 54.25 tons when filled with pressurised water. Manufacturing the Pipelines. One company with a huge involvement in the manufacture of the HAIS pipeline was W T Henley of Gravesend. An idea of the vastness of the project is conveyed by the fact that Henley's alone used 8,000 tonnes of lead and 5,600 tonnes of steel wire and strip, as well as large quantities of other materials. Transporting and handling these huge bulks under war conditions was an enormous task and great credit is due to the suppliers whose ready co-operation made these vital supplies available. Glovers Cables, located in Manchester's Trafford Park Industrial Estate take the first manufacturing machines and used a conveyor belt system to build the 72 miles on continuous HAIS flexible pipe. The conveyor and its cable hauling units formed an unmistakable landmark that extended from the end of Glovers works and delivered the cables to either a cable-ship berthed on the Manchester Ship Canal alongside Trafford Park, or coiled the unwieldy cable alongside the canal wharf for later shipment. Also involved in the production was British Insulated Callender's Cables (BICC) of Erith, Kent, England ... but even this was not enough to meet the demand so USA firms ( General Electric, Phelps-Dodge, Okonite Callenders and General Cable) were drafted in. Of the 710 miles of PLUTO pipeline manufactured 140 miles came from the USA. The production of the HAMEL steel pipe started at Woolwich in September 1943 and a number of lengths had been completed a year later, one of which was 40 miles long and weighing in at 2,200 tons. Many regarded PLUTO as yet another wild fantasy of Combined Operations H.Q. but concerns were alleviated to some extent by the concurrent use of 'Tombola,' a conventional tanker-ship to shore storage system. This was set up on the Normandy ports at Port-en-Bessin and at Ste. Honorine, two miles further to the west, and was fully operational by June 14 1944.
Operational Use. The land based installations in the UK were in place in readiness for the invasion and Operation PLUTO formally started on 12 August 1944, more than two months after D-Day. As the Allies advanced, the pipeline was extended from Mont Cauvin towards Carentan. In August Pluto Minor was connected to the major system coming from the Isle of Wight via Cherbourg. The main 'Pipeline Under the Ocean' operation was initially based on Cherbourg and the laying process, over the 70 miles from the Isle of Wight to the Cherbourg peninsula, took as little as 10 hours. However, on the approaches to the beach, there was an unforeseen difficulty which catapulted ordinary individuals into dealing with issues well beyond their normal experience and sometimes drawing on long-forgotten solutions. One such concerned pulling the HAIS pipe up the beach at Cherbourg. A mobile winch was needed and when the engineers calculated the power required there was much shaking of heads and dark muttering that no such device existed. There was however a most unlikely solution from an earlier age as information taken from a 1965 article by Captain J.F. Hutchings explains. ‘It appears that a naval officer charged with the task of getting the pipelines across the Channel was having difficulties getting the pipes ashore. The officer recalled a boyhood memory of watching two steam powered ploughing engines at work. A phone call to the Ministry of Agriculture & Fisheries resulted in six engines being allocated to the PLUTO project. It appears that engines were sent to Sandown, Thorpes Bay, Lepe at the entrance to Beaulieu River on the mainland opposite Cowes, Hengistbury Head near Bournemouth for the PLUTO training exercise area, and one to France which was given the name STEVE - a Fowler class BB1 with works No 15220, built in 1918. The engine's modified hauling drum exerted a 14-ton pull to bring the pipes ashore.’ By the time the two HAIS flexible pipelines and two HAMEL steel pipelines were pumping petrol the Allied armies were well on their way to Belgium. When the Allied advance had progressed to the Belgium frontier the length of the supply lines needed to be shortened. Another set of 11 HAIS pipelines and 6 HAMEL pipelines were laid in a swept channel two miles wide between Dungeness and Ambleteuse near Boulogne in a operation called Dumbo. In all about 500 miles of pipeline were laid in an average laying time over the 30 mile stretch of about 5 hours. In January 1945 the system delivered a disappointing 300 tons but by March this had increased to 3000 tons and later still to 4000 tons. This amounted to over 1,000,000 gallons per day giving a total of 172,000,000 gallons delivered in total up to the end of hostilities. During the operation to lay the cables an HQ ship, several cable ships, tugs, trawlers and barges were employed on this specialised work - a total of 34 vessels with 600 men and officers under Captain J.F.Hutchings. Captain Harry Butcher, Naval Aide to Eisenhower, said: ’ it would in itself be regarded as a considerable enterprise in normal times’. Churchill said that “Operation Pluto was a remarkable feat of British engineering, distinguished in its originality, pursued with tenacity and crowned with complete success. This creative energy helped to win the war.”
The Model With the specification data of the pipeline it was possible to model on paper how the pipeline could be loaded and transported by railway. The data is tabulated below and it can be seen that the total weight of a 72 mile pipeline is 3,600 tons. Table 1: PLUTO Pipeline specifications. Actual Dimensions Ft/mile Inches ton/mile Miles Feet Tons total length of pipe 72 miles 5,280 72 380,160 outside diameter of pipe 4.5 0.375 weight of pipe per mile 50 3,600 The train of wagons to transport the pipeline is summarised in the table below and shows that the 10 tube wagons from the original statement would have to carry 360 tons each. The first column uses the 10 wagon for 72 miles of pipe as the starting point. The numbers o flayers required, in row 7, is clearly unrealistic for safe loading onto a normal railway wagon. However, by increasing the number and capacity of wagons in the next five columns the numbers start to look more achievable. It is assumed that the normal tube wagons of 1944 are of 30 or 40 foot length and 21-25 tons capacity. In the final column we find that we can carry 3,600 tons of 72 miles of pipe on sixty 60 foot long wagons with 60 tons capacity. Table 2: Railway Transportation Capacity Data. Capacity of Railway Wagons weight per wagon (total weight/number) 360 360 180 120 90 72 60 wagon length (Feet) 30 40 40 50 60 60 60 number of wagons 10 10 20 30 40 50 60 wagon width (feet) 9 9 9 9 9 9 9 length of total train (feet) 300 400 800 1500 2400 3000 3600 one layer of pipe (feet) (see Note 1) 690 890 1780 3270 5160 6450 7740 number of layers required 551 427 214 116 74 59 49 pipe stowage cross section (sq ft) 103 80 40 22 14 11 9 The pipeline is a continuous length of 380,000 feet, and I have assumed that it would be laid onto the wagons in the following manner. Diagram 3: Plan of wagons and arrangement of pipe layers. file:///C:/Users/IBM_AD%7E1/AppData/Local/Temp/msohtml1/01/clip_image001.gif Taking into account the width of the wagon of 9 feet, sixty 60ft wagons can accommodate one layer of pipe to give a total of 7,740 feet, and with 49 layers the entire pipeline can be carried in one length. The diameter of the pipe is 4.5 inches and, in the scale diagram below, the 49 layers of pipe could be arranged in 3 stacks on a wagon of 9 foot width. The height of the stacks would be seven feet, although the steel pipe could not be laid in the 9 foot radius of the curvature for the first and last wagon. To lay the HAMEL steel pipelines in one overnight operation across the Channel the pipes were rolled onto floating drums called Conundrums. These were 50 foot in diameter and 60 feet wide so whilst the steel pipes were capable of a curvature of at least 25 feet, it is improbable that they could be laid with nine foot radius curves. The HAIS flexible pipelines were probably much more likely to take a 9 foot radius curve.
Diagram 4: Scale drawing of pipe layers in cross section. file:///C:/Users/IBM_AD%7E1/AppData/Local/Temp/msohtml1/01/clip_image001.gif Summary and Conclusion. The innovators of the pre-invasion preparations have clearly pushed the boundaries of the available technology to meet the challenges of the day. It was a massive undertaking to launch an amphibious and airborne invasion of a defended coastline. The scope and depth of the preparations to ensure the eventual success of the operation has been an incredible lesson in planning and organisation. The design and manufacture of the PLUTO pipeline was, indeed a masterful project of immense proportions. But, the project to model the transportation of a 72 mile pipeline on 10 railway wagons has proved to be a dead end. The best model which could be aimed for is much shorter flexible pipeline on 10 wagons. References: 1. Combined Ops website: http://www.combinedops.com/pluto.htm: provided much of the text for this article. 2. Archive, The quarterly journal for British Industrial and transport History, Issue 42; was a key source of detailed data. 3. Pluto: WW2’s best kept Secret: Bob Knight, Harry Smith, Barry Barnett; Bexley Council;
