Petroleum Warfare Department facts for kids
The Petroleum Warfare Department (PWD) was a special government group set up in Britain in 1940. This happened during World War II when it looked like Germany might invade the country. The PWD's first job was to find ways to use petroleum (oil) as a weapon. They helped create many flame-throwing weapons. Later in the war, the PWD also played a big part in two other important projects: Fog Investigation and Dispersal Operation (known as FIDO), which helped clear fog from airport runways so planes could land safely, and Operation Pluto, which built fuel pipelines under the English Channel to supply Allied forces after the invasion of Normandy in 1944.
Contents
How the Department Started
World War II began in September 1939, but not much fighting happened in Western Europe until Germany attacked France and other nearby countries in May 1940. After France fell and British soldiers had to leave Dunkirk in June 1940, Britain faced a real threat of invasion from Germany.
To prepare for this, Britain worked hard to make its Royal Navy, Royal Air Force, and Army stronger. They also needed to replace all the equipment left behind at Dunkirk. Many new weapons were developed, especially those that didn't need rare materials.
Even though oil from the Middle East had stopped coming, Britain had plenty of oil. Supplies meant for other parts of Europe were filling British storage tanks. Oil for regular cars was strictly limited, not because there wasn't enough, but to stop many cars from gathering in one place.
If an invasion happened, the British would need to destroy their oil supplies so the enemy couldn't use them. By mid-June, gas stations near the coast were emptied or had their pumps turned off. Garages everywhere had to plan how to stop invaders from getting their fuel.
On May 29, 1940, while soldiers were being evacuated from Dunkirk, Maurice Hankey, a government minister, joined a committee. Hankey had a strong idea: use burning oil to stop an invasion. He believed oil shouldn't just be destroyed, but used against the enemy. By late June, Hankey shared his ideas about using oil in war. On June 5, Prime Minister Winston Churchill approved experiments, with Hankey watching over them.
Donald Banks Joins In
Donald Banks was a brave soldier in World War I. After the war, he worked for the government. In 1939, when the war started again, he was free to join the armed forces.
Banks was sent to France with the 50th (Northumbrian) Infantry Division. He got along well with his commander, Major-General Giffard LeQuesne Martel, who liked trying new things. In May 1940, Banks saw a bombed oil tanker burning at sea. He later said, "Masses of the blackest smoke pillared up... in the vast lake of fire... a flame blazed and leapt like an angry volcano." This sight stayed with him and inspired his later work with flame weapons. His division was later evacuated to England.
In July 1940, Banks met with Geoffrey Lloyd, the Secretary for Petroleum. Lloyd shared a big idea from Hankey: "Flame all across Britain... We will burn the invader back into the sea."
Banks thought about Lloyd's ideas and talked to other soldiers. Some were doubtful, but others were excited. Banks, who preferred real fighting to office work, wasn't sure at first. He suggested that oil weapons should be developed locally. But Lloyd insisted, and Banks was ordered to take on special duties. On July 9, 1940, the Petroleum Warfare Department was officially created. It started in three small rooms with only a few staff who didn't have much technical experience.
Flame Traps to Stop Invaders
The PWD got ideas from events during the retreat to Dunkirk. For example, in May 1940, a group of soldiers used vehicles and furniture to block a road in Boulogne. When an enemy tank tried to push through, they punctured petrol tanks and set them on fire. A huge flame went up, forcing the tank to back off. This burning roadblock gave them time to build another one.
The new department quickly set up experiments in Kent. Many early ideas didn't work, but they soon developed the first useful weapon: the static flame trap.
Static Flame Traps
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A static flame trap could cover a road (about 60 to 150 feet long) with fire and smoke very quickly. It was a simple setup of pipes with small holes placed along the road. These pipes were connected to larger pipes that led to a fuel tank placed higher up. The fuel was a mix of 25% petrol and 75% gas-oil, which couldn't be used in enemy vehicles. To activate it, someone just had to open a valve, and a Molotov cocktail (a bottle filled with burning liquid) would ignite the fuel, creating a huge fire. The best places for these traps were where vehicles couldn't easily escape, like a sunken road. They were also carefully hidden, sometimes disguised as handrails.
The pipes and valves were easily found from gas and water companies. Usually, gravity was enough to make the oil spray out, but sometimes pumps were used.
Later versions were more advanced. They could be ignited from a distance. One system used oil pressure to squeeze glycerine onto potassium permanganate, which would then catch fire by itself. Another method used two small tubes with acetylene and chlorine gases. When these gases mixed, they would ignite. This system could be turned on and off. The flame fougasse (explained below) later offered a remote electrical ignition that was instant but could only be used once.
About 200 static flame traps were installed, mostly by oil company workers.
Mobile Flame Traps
Besides the fixed traps, mobile units were also made. The main design used a 200-300 gallon tank on the back of a lorry. It had a petrol-powered pump and 75 feet of armored rubber hose. Two nozzles could shoot flames 60-70 feet.
Because pumps were scarce (they were needed for fighting fires from bombings), a simpler mobile trap was also designed. This used several 12-inch wide, 12-foot long metal drums filled with 43 gallons of fuel. These could be carried on a vehicle and quickly set up. They would be placed along a road, with a hose leading to a nozzle. A pull string opened a valve, and Molotov cocktails provided the fire.
Flame Fougasse
The PWD soon got help from Henry Newton and William Howard Livens, who were known for designing mortars in World War I.
Livens had worked on flame-throwing weapons before. One of his ideas for the PWD was simple but effective: blowing up a barrel of oil on the beach. This impressed many high-ranking officers, who quickly moved away from the test site! The work was dangerous. Livens and Banks almost got hurt when an electrical short circuit accidentally set off some weapons.
These experiments led to the "flame fougasse." This was a 40-gallon steel drum buried in an earthen bank, with only its front end showing. An explosive at the back of the drum would rupture it, shooting a jet of flame about 10 feet wide and 30 yards long. This weapon was named after an old medieval weapon called a fougasse, which used gunpowder and rocks. The flame fougasse was shown to important leaders like Clement Attlee and Maurice Hankey in July 1940.
Other versions included the "demi-gass," a barrel placed horizontally that would flip towards the target, and the "hedge hopper," which would bound over hedges or walls, making it easy to hide.
About 50,000 flame fougasse barrels were given out. Most were set up in 7,000 "batteries" (groups of barrels) mainly in southern England and Scotland. A common setup was a four-barrel battery.
Tricky Waters: Burning the Sea
Operation Lucid
The PWD also looked into burning enemy barges before they could reach the English shore. One idea was to explode a ship full of oil. This was tested with a tanker called Suffolk, which was blown up with 50 tons of oil. Another idea was to use a special matting to hold oil in place on the water, creating a long flaming ribbon. These ideas didn't become real defenses.
However, the Suffolk test led to a bigger idea: burning invasion barges while they were still in port. This plan, called Operation Lucid, started in June/July 1940.
Three old tankers were quickly turned into fire ships, loaded with over 2,000 tons of oil and explosives. The operation was tried several times in September–October 1940, but bad weather, unreliable ships, and even a mine damaging a destroyer stopped it. By November, the invasion threat had passed, and Lucid was put aside.
The "Burning Seas" Story
From the very beginning, the PWD experimented with "setting the sea on fire." They knew this weapon would not only destroy the enemy but also create fear.
Interestingly, a plan was made to spread a rumor that such a weapon already existed, even before the first tests were successful. This was a clever trick, a "bluff," and it became Britain's first major propaganda success of the war. Propaganda is like spreading information (sometimes true, sometimes not) to influence people.
The rumor was that a bomb could spread a thin layer of liquid on the water and then set it on fire. This story was whispered in neutral cities like Stockholm and Lisbon in July or August 1940. Soon, captured German pilots confirmed that the rumor was widely known.
The Germans even started experimenting with burning floating oil themselves. On August 18, they set 100 tons of oil on fire, which burned for 20 minutes. This was almost a week before the British had their first successful test!
In Europe, the "burning seas" story grew. It even included tales of a German invasion attempt that was stopped by burning oil on the water. An American war reporter in Berlin heard these stories. He noticed many German soldiers with burns arriving on hospital trains and wondered if the rumors were true. It's likely these soldiers were hurt in British bombing raids on ports, but the rumors made it sound much worse.
The British got better at spreading these "inspired rumors," called SIBS. New SIBS included stories of "thousands of floating German corpses" and fish feeding on them. In October, the RAF even dropped leaflets in German, French, and Dutch with phrases like "the sea smells of petrol here" and "see how well the captain burns!" These leaflets reinforced the rumors of a failed invasion.
The German command knew the stories weren't true, but the propaganda was aimed at their soldiers who might have to invade England. Berlin was forced to officially deny the rumors. Even in the UK, the stories spread, causing confusion and questions in parliament. This "burning sea" lie was a big propaganda win for Britain. It likely led to many myths about a German invasion being stopped by sea-burning bombs, like the famous Shingle Street Mystery.
Flame Barrage
Despite the propaganda, the PWD continued to work on actually setting the sea on fire. Early tests were not great, but Geoffrey Lloyd didn't give up. On August 24, 1940, at the Solent, 10 tanker wagons pumped oil down pipes into the water. The oil was set on fire, creating a huge wall of flame. The heat was so intense that people watching had to move back. It was dramatic, but the conditions were perfect: calm, warm water and light winds.
Many more experiments followed, with lots of setbacks. Pipes were torn up by storms, and engineers were hurt by beach mines. They found that cold temperatures made ignition harder, and waves quickly broke up the oil into small, ineffective patches.
On December 20, 1940, senior generals watched a demonstration, but it was very disappointing. Only a few small pools of oil burned in the cold, cloudy weather. Banks called this day "Black Friday" for the PWD.
General Alexander suggested moving the pipes above the high tide line. After several months, this worked: oil was sprayed and burned over the water, not on it. In February 1941, military leaders approved installing 50 miles of flame barrage along the coast.
However, General Brooke wasn't convinced. He worried about the wind, the smoke screen it created (which might help the enemy), and how easily it could be bombed. Also, materials were scarce. So, the plans were cut back again and again. In the end, less than 10 miles of flame defense were completed in places like Deal, St. Margaret's Bay, and Studland Bay.
Portable Flamethrowers
During World War I, the British had developed flamethrowers, but work stopped and records were lost.
Work restarted in 1939, looking into how to design valves, nozzles, and fuels. Other people were also working on portable flamethrowers for the Army. The PWD developed a simple "Home Guard flamethrower."
Home Guard Flamethrower
This wasn't a flamethrower in the usual sense, but a small, semi-mobile flame trap. From September 1940, 300 Home Guard units received a kit: a 50-65 gallon barrel, 100 feet of hose, a hand pump, and instructions. The barrel was put on an 8.5-foot long hand cart made from wood and old car wheels. The nozzle was simple, made from gas pipe and a food can to keep a flame going. It was filled with a 40/60 fuel mix.
The Home Guard flamethrower was light enough for five or six men to wheel it. It would be used in ambushes with Molotov cocktails. The hand pump could shoot a flame up to 60 feet for about two minutes.
Harvey Flamethrower
The Harvey flamethrower came out in August 1940. It was made from common parts like farm equipment wheels and compressed air cylinders. It had a steel cylinder holding 22 gallons of creosote and a compressed nitrogen bottle. All this was mounted on a sack truck (like a trolley). A 25-foot armored hose connected to a 4-foot long lance with a nozzle. Paraffin-soaked cotton provided the ignition. It could shoot a jet of fuel for about 10 seconds, up to 60 feet. Like the Home Guard flamethrower, it was for ambushes. The operator could direct the flames from behind cover, like a brick wall.
Marsden Flamethrower
The Marsden flamethrower, probably from June 1941, was a backpack unit. It held 4 gallons of fuel, pressurized by nitrogen gas. A flexible tube connected the backpack to a "gun" operated by a lever. It could give 12 seconds of flame, divided into many short bursts. It was heavy and awkward. Only 1,500 were made, and few were actually used.
Neither the Harvey nor the Marsden flamethrowers were popular with the Army. Most ended up with the Home Guard. The Marsden was replaced in 1943 by the "lifebuoy" flamethrower, named for its round fuel tank.
Vehicle-Mounted Flamethrowers
Cockatrice
The PWD also oversaw the development of flamethrowers mounted on vehicles. The first prototype, called Cockatrice, was shown in August 1940. Reginald Fraser, a car company director, developed a flamethrower that shot petrol with a thicker outer layer. He thought this would stop the fire from going back to the fuel tank.
Fraser built an experimental vehicle on a Commer lorry chassis. A demonstration of this vehicle was "terrifying." It shot a mix of diesel oil and tar about 100 yards, with a flame 30 feet wide, using 8 gallons of fuel per second. It often "appalled and horrified" generals and admirals.
The idea was that invading paratroopers landing on an airfield would be very vulnerable for about a minute after landing. A fast-moving vehicle with a flamethrower could cover them in fire before it was destroyed. The Cockatrice had a rotating weapon that could aim up to 90 degrees and had a range of about 100 yards. It carried two tons of fuel and used compressed carbon monoxide to push the flame. Sixty "Light Cockatrices" were ordered for protecting Royal Naval Air Stations, based on an armored Bedford QL vehicle. Six "Heavy Cockatrices" were built for RAF airfield defense, using a larger AEC Matador chassis. The Army wasn't very interested, so it wasn't mass-produced.
The Cockatrice flamethrower was also put on small ships. German pilots often attacked coastal vessels by flying very low. The idea was that a vertical flamethrower might stop these attacks. An experiment showed the flame could reach 300 feet vertically! Even though it didn't seem to do much damage, intelligence reports showed that German attacks started happening at much higher altitudes.
The Navy also ordered a version of Cockatrice that could be put on a landing craft. This was called a landing craft assault (flame thrower) or LCA(FT), but it doesn't seem to have been used in battle.
Ronson
The first British vehicle flamethrower for the regular army was the Ronson, named after the cigarette lighter company. Fraser developed it from his Cockatrice designs. The Ronson was mounted on a Universal Carrier, an open-topped, lightly armored tracked vehicle. The British Army initially rejected it because it needed a greater range.
However, Lieutenant-General Andrew McNaughton, commander of Canadian forces in Britain, was very interested. He ordered 1,300 Ronsons on his own! The Canadians later developed the Wasp Mk IIC (see below), which became the preferred model. The Ronson was also attached to the Churchill tank. A Churchill MkII tank was modified in 1942 with two Ronson projectors on the front. Fuel was held in tanks at the back. This design was later simplified to a single projector and called the Churchill Oke. Three Churchill Okes were used in the Dieppe Raid but didn't get to use their flamethrowers in combat.
The Ronson also caught the attention of the United States. They used it to replace the main gun on older M3A1 tanks, calling it Satan. These flamethrower tanks saw action in the Pacific War and during Operation Overlord (the D-Day invasion).
Wasp
By 1942, the PWD improved the Ronson flamethrowers to have a range of 80–100 yards. In September 1942, this improved version was produced as the Wasp Mk I. One thousand were ordered and delivered by November 1943. The Wasp Mk I had two fuel tanks inside the carrier and a large projector gun mounted on top. However, it was quickly replaced by the Wasp Mk II, which had a handier flame projector mounted at the front where the machine gun usually was. This made it easier and safer to aim.
The Wasp Mk II was used in the Invasion of Normandy in July 1944. Wasps were mainly used to support infantry (foot soldiers), while the Crocodile (below) was used with armored units. They were very effective weapons, feared by the Germans. Often, enemy soldiers would stop fighting when Wasps arrived.
Soon, the Wasp Mk IIC, developed by the Canadians, became popular. The Canadians made it so the Universal Carrier could still do its normal jobs while carrying the flamethrower. They moved the fuel tank to the back of the vehicle, making room for a third crew member who could carry a machine gun. This made the Mk IIC much more flexible. By June 1944, all Wasp production switched to the Mk IIC, and older Mk IIs were updated. Many Wasp Mk IICs also got extra armor on the front.
Valentine
George John Rackham, a tank designer, developed a flamethrower called the Heavy Pump Unit. It could shoot liquid at 750 gallons per minute, creating an amazing jet of flame. This unit was mounted on a large lorry chassis. There was also a smaller version on a two-wheeled cart that could be towed. A demonstration of the Heavy Pump Unit impressed the Secretary of State for War. Soon, the PWD was asked for a similar weapon mounted on a tank.
Work began on two prototypes based on the Valentine tank. Both carried fuel in a trailer. One used gas from slow-burning cordite charges to create pressure, giving a range of 80 yards. This system had a projector in a small turret that could be aimed. The other prototype, from the PWD, used compressed hydrogen for pressure, giving a range of 85 yards. This version was simpler and required moving the whole tank to aim. Even so, the PWD system won because it could maintain gas pressure for continuous firing, while the other had to wait between bursts. The two development teams then merged.
Churchill Crocodile
The PWD also worked on a flamethrower for the Churchill tank. Work was slow at first because the Wasp was a higher priority. The first prototype was ready in early 1942. The design used lessons from the Valentine tank prototypes. Fuel and pressure for the flamethrower were carried in an armored trailer, weighing about 6.4 tons. The trailer held two fuel tanks (400 gallons total) and five compressed-air cylinders.
The connection between the trailer and the tank was very strong, allowing the tank to move in many angles. An armored hose carried fuel to a projector mounted where the hull machine gun usually was. This meant the gunner could use the same sight for both. The tank's normal operations were not limited, and it kept its main gun. The trailer did make the tank less maneuverable, but it could be quickly detached.
The Crocodile flamethrower had a range of up to 120 yards. The pressure had to be built up on the trailer just before use, as it couldn't be maintained for long. It used 4 gallons of fuel per second. Refueling took at least 90 minutes. The fuel could burn on water and set fire to woods and houses. It could also shoot a 'wet' burst of unlit fuel into trenches or buildings, then ignite it with a second 'hot' burst.
In 1943, Percy Hobart saw a Crocodile. Hobart was in charge of the 79th Armoured Division, which created many special armored vehicles ("Hobart's Funnies") for the Normandy invasion. Hobart pushed for the Crocodile's production, and sixty were ready just in time for D-Day.
Pipeline Under the Ocean (PLUTO)
Operation Pluto (Pipe-Lines Under The Ocean) was a secret project to build oil pipelines under the English Channel between England and France. This was to supply fuel for the Allied invasion of France (Operation Overlord).
In April 1942, plans for the invasion were being made. Thousands of vehicles would need huge amounts of fuel. Geoffrey William Lloyd, the Minister for Petroleum, asked Lord Louis Mountbatten if the PWD could help. Mountbatten replied, "Yes, you can lay an oil pipeline across the English Channel." Pipelines were needed because oil tankers could be slowed by bad weather, attacked by German submarines, and were needed for the war in the Pacific.
Laying a pipeline during an invasion was very difficult. The pipe had to withstand huge pressure from 600 feet of seawater and high internal pressure from the pumped oil. It also had to be flexible but strong enough to resist currents and rocks. Everything had to be prepared in great secrecy. Pipe laying couldn't start until the invasion began and had to be finished quickly.
HAIS Pipeline
On April 15, 1942, Arthur Hartley, an engineer, learned about PLUTO's challenges. Hartley suggested using a modified underwater power cable. This idea was adopted and became known as the HAIS pipeline. It had an inner lead tube surrounded by layers of paper, cotton, and jute yarn, protected by steel tape and steel wires. The design was improved after tests, adding more steel tape layers and making the lead pipe without a seam. In March 1943, a 30-mile HAIS pipeline was successfully laid between Swansea and Ilfracombe, supplying petrol for over a year. The pipe's internal diameter was increased to 3 inches to pump three times more petrol.
A company called Callenders produced HAIS pipeline sections. The lead pipe was made in 700-yard sections, then tested under pressure. Special workers, Frank and Albert Stone, were hired to make the critical joints by welding. Each joint took about two and a half hours. They worked 18-20 hour shifts and had to keep their work secret.
As the pipeline was made, it was coiled into huge 60-foot diameter, 10-foot high coils. About 250 miles of HAIS pipe were made in the UK, and another 140 miles in the US.
Four ships were converted to carry and lay HAIS pipeline. The larger ships, HMS Latimer and HMS Sancroft, could carry two lengths of pipe (enough for the 70-mile distance to Normandy). Smaller ships laid pipes from Kent to the Pas de Calais. Special barges laid pipes in shallow water from the ships to the shore.
Special couplings were designed to join pipe lengths at sea in about 20 minutes. These couplings had thin copper discs that would burst when the fuel pumps started, allowing oil to flow.
HAMEL Pipeline
An all-steel pipe, called HAMEL, was also developed as a backup. This was a 3-inch steel tube, similar to onshore pipelines. Engineers noticed how flexible long lengths of steel pipe were and thought sections could be welded together to make a very long pipe. Special welding machines were used to make thousands of strong joints.
Because the steel pipe couldn't be easily twisted, it couldn't be coiled in a ship's hold like the HAIS pipe. So, a special barge, HMS Persephone, was fitted with a large wheel to wind and unwind the pipe without twisting. This ship laid pipes from the British mainland to the Isle of Wight, which served as a test and a vital link in the oil network.
For longer distances, a 30-foot diameter floating drum was designed, called HMS Conundrum. Long sections of pipe were welded together and wound onto this drum, like thread on a bobbin. The Conundrum could carry up to 80 miles of pipeline and six were built.
Towing a Conundrum was tricky at first. Donald Banks, who wasn't a sailor, suggested that the tugs' wakes were pushing the Conundrum backward. Separating the tugs improved performance, and a third small tug helped with steering.
An onshore pipeline system already existed in Britain, feeding oil from tankers to airfields. PLUTO was connected to this system at Lepe. From there, a HAMEL pipe went under the Solent to the Isle of Wight, then overland to Shanklin.
Pluto in Action
The invasion of Normandy began on June 6, 1944. Fuel was initially brought ashore in thousands of jerrycans. Ship-to-shore pipelines, called TOMBOLA, were laid as fuel use increased.
PLUTO was supposed to lay its first pipeline 18 days after D-Day, but this didn't happen. It took longer to capture Cherbourg, and the port was heavily damaged and mined. The first cross-Channel pipe, a HAIS, was laid on August 12 by HMS Latimer, but it was damaged at the last minute. Two days later, another attempt failed. The first HAMEL pipeline attempt on August 27 also failed because of barnacles on the Conundrum. Problems continued with connecting pipes to the shore, causing leaks and abandoned pipes.
Finally, on September 18, a HAIS pipe was successfully connected and tested. Four days later, fuel pumping began, delivering 56,000 gallons daily. On September 29, a HAMEL pipeline was also connected.
Only one HAIS and one HAMEL pipeline were successfully laid. While they helped, the delays meant PLUTO didn't deliver fuel when it was most needed. What it did deliver was small compared to the fuel brought in by ships. Even this partial success didn't last long: both pipelines failed in early October. By then, the Allies had captured the deep-water port of Le Havre and were deep into France. Attention shifted to a shorter route across the Channel to Calais.
Pipe to Pas de Calais
A pumping station called DUMBO was set up at Dungeness in Kent. This station received oil from other British ports. The pipeline route was chosen to make the enemy think the oil was going to the area between Hythe and Folkestone, suggesting an invasion at the Pas-de-Calais. Pumps were hidden in seaside homes, and pipes were covered in the shingle (small stones) of the headland.
The first HAIS pipe was laid on October 10. Lessons from earlier problems helped them overcome the difficulties of connecting to the shore. However, bad weather and less official enthusiasm slowed progress. Fuel pumping didn't start until October 27. By December, only four HAIS pipes were working, delivering just 700 tons of fuel daily.
HAMEL pipes were harder to bring ashore, especially in bad weather. This was solved by adding lengths of HAIS pipe to the ends of HAMEL pipelines as they were wound onto a conundrum, making shore connection much easier.
Seventeen pipelines were laid from Dungeness to Boulogne, with up to 11 working until the end of the war. This route could deliver 1,350,000 gallons per day and often delivered over 1,000,000 gallons daily. While impressive, this was still only about 10% of the fuel transported across the Channel, and it came too late to affect the main campaign. The pipelines weren't designed to last long; steel HAMEL pipes usually failed within weeks due to friction with the seabed, and HAIS pipes lasted a little longer.
PLUTO faced bad luck, like delays in capturing Cherbourg, and it was hard to turn test results into real-world success fast enough. Still, it was an amazing technical achievement under very tough conditions.
Recovery After the War
PLUTO stopped working in July 1945, a few months after the war in Europe ended. Because the pipes were a danger to ships, the Royal Navy cut them and removed sections near the shore. Starting in August 1946, the former HMS Latimer was used to salvage the pipes. They used a grapple to find a pipeline and pull it onto the ship.
HAIS pipes were in good condition, and their high lead content made them valuable. Each pipe could be cut once and coiled in the ship's hold. The recovered lead was melted into ingots, the wires were straightened and used as rebars (for concrete), the steel tapes were flattened for cardboard boxes, and the jute was burned as fuel.
The HAMEL pipes were also valuable but less flexible, so they had to be cut into shorter lengths on the ship's deck. Cutting both types of pipes was dangerous because they still contained petrol. The contaminated petrol was recovered and cleaned, yielding about 66,000 gallons of useful fuel.
The salvage operation lasted three years. Of the 25,000 tons of lead and steel originally used, 22,000 tons were recovered.
Fog Investigation and Dispersal Operation (FIDO)
From the start of the war, many aircraft were lost in accidents during foggy landings. Fog was very dangerous, especially for tired or injured pilots in planes low on fuel. On the night of October 16/17, 1940, 73 bombers flew raids. Three were shot down, but ten crashed on landing. Prime Minister Churchill demanded that something be done.
Earlier, Professor David Brunt had calculated that if the temperature of fog was raised by about 5 degrees Fahrenheit, it would disappear. Some tests were done between 1936 and 1939 using burners and a petrol-alcohol fuel mix. While they didn't clear a lot of fog, they showed it was possible. But no more work was done.
As bombing raids increased, more planes flew longer distances, and more accidents happened. Despite Churchill's order, nothing was done to reduce losses from bad weather. Finally, in September 1941, military leaders recommended restarting the fog dispersal work. But the idea met resistance and was postponed.
By September 1942, it was clear that many planes were being lost unnecessarily, and bad weather was limiting operations. The Secretary of State for Air recommended that the PWD try fog dispersal tests. Within 24 hours, Churchill sent a personal message: "It is of the greatest importance to find a means to dissipate fog at aerodromes so that aircraft can land safely. Let full experiments to this end be put in hand by the Petroleum Warfare Department with all expedition. They should be given every possible support."
Lloyd, Banks, Hartley, and other engineers met. Lloyd visited fruit farmers who used heaters to protect crops. Hartley arranged for an empty reservoir to be used for experiments. Walker studied fog on long walks. Experiments quickly began, with large tests at the reservoir and smaller ones in a disused indoor ice rink where different weather conditions could be simulated.
In some early tests, Wasp flamethrowers were used. A Cockatrice fired six 1.5-second bursts in thick fog, clearing the air nearby.
The first special burner, called Four-Oaks, used a petrol and alcohol mix, but it produced too much smoke. On November 4, 1942, a test was done with two rows of Four-Oaks burners. A fireman climbed an 80-foot ladder and disappeared into the fog, only to reappear when the burners were on. However, the Four-Oaks burner made as much smoke as it cleared fog and didn't heat enough. Experiments with coke burners worked better at first, but they couldn't be controlled and caused smoke.
A new burner, Haigas (later Mark I), was developed. Haigas used petrol that was preheated to become a vapor before burning, making it more efficient and less smoky. An experimental system was installed at Graveley, Cambridgeshire, and tested on February 18, 1943. The pilot, Air commodore Don Bennett, said the glare was considerable but not a problem. Graveley became the first working FIDO site, and the system quickly expanded.
The Haigas (Mark I) burner was 50 feet long, made of four connected pipes. The fuel flowed through the pipes, getting heated and vaporized by the burners' heat. This made it burn efficiently without much smoke.
Later burner designs, called Haigill (Mark II to Mark VI), were simpler and more efficient, using only three pipes. Even later, the Hairpin burner was developed. It was set in a special trough in a concrete trench at ground level, making it less in the way of air operations.
It's hard to say exactly how valuable FIDO was. About 700 aircraft landed safely with FIDO working in foggy conditions, and about 2,000 landed with FIDO helping them see the runway in limited visibility. Around 3,500 aircrew may owe their lives to FIDO, and for perhaps 10,000 others, it made a dangerous situation easier. FIDO was briefly used for commercial flights but became unnecessary as new landing systems were developed.
Legacy of the PWD
When the war in Europe was almost won, the work of the Petroleum Warfare Department was widely shared as an example of British cleverness. Newsreels told the public how flamethrower weapons were made to defend the country and how the PLUTO and FIDO projects helped win the war.
The PWD planned a traveling exhibition of its achievements. When the war ended, they changed plans and held a temporary exhibition at the Imperial War Museum. From October 1945 to January 1946, over 20,000 people visited to see details of flame-throwing weapons, the FIDO system, and PLUTO. Donald Banks also wrote a book about the PWD's activities called Flame Over Britain.
Engineer and author Nevil Shute joined the Navy and worked in a weapons development group. Based on his experiences, he wrote Most Secret, a novel about a fishing boat with a Cockatrice-like weapon. The book was written in 1942 but wasn't allowed to be published until 1945.
Today, you can see a PLUTO pump on display at the Bembridge Heritage Centre and at the Isle of Wight Zoo in Sandown. There's also a book called Where PLUTO Crossed the Path that helps people find markers along the pipeline route on the Isle of Wight.
See also
