Thread by @usacac

OPERATION OUTWARD

During World War II, particularly throughout the London Blitz, the British used barrage balloons as a means of protecting cities and important ground targets.

These massive, gas-filled balloons would be tethered to the ground via steel cables and allowed to float at around 5000-feet. The balloons could obstruct view of targets below. Luftwaffe pilots had to fly above them or risk maneuvering below them.

During the London Blitz from September 1940 until May 1941, over 100 Luftwaffe aircraft reportedly crashed or were forced to land as a result of these barrage balloons.

On 17 SEPT 1940 a storm hit England and with it came strong winds that freed many of the barrage balloons from their anchors. The balloons were blown over the North Sea with their tethering cables dragging the whole way.

“Within hours, reports of electrical outages in Denmark, Sweden, and Finland began to come in.” 👀

“The balloons’ heavy tethering cables had struck high-voltage overhead electric transmission and distribution lines, and the resulting short circuits caused power outages affecting electrified railroads and even whole cities.”

“One balloon strike resulted in the toppling of the broadcast tower of the Swedish international radio service.”

One report read:

“On Wednesday evening the Swedish west coast witnessed a great ‘invasion’ by foreign barrage balloons… the barrage balloons came over in such numbers that at times the sky was lit up with sparks when the balloon cables touched electric wires.”

British leadership realized that “if wayward balloons could accidentally cause damage to overhead electric power transmission lines, perhaps a purpose-designed and deployed balloon system could do even better.”

Balloon Command was responsible for the barrage balloons. The Air Vice Admiral of Balloon Command wrote in 1940:

“Since the outbreak of war, I have had constant complaints from the electricity distributors regarding the damage done in this country by balloons that have broken away from their moorings.” He suggested “… advantage might be taken of this to impede and inconvenience the enemy.”

Winston Churchill on 19 SEPT 1940, wrote a memo to the War Cabinet:

“We may make a virtue of our misfortune.”

And from this came the idea for Operation Outward, “an offensive weapon scheme that the British hoped would carry the battle to Germany and the occupied countries less expensively and more safely than British night bomber attacks.”

The British Military assumed balloon attacks would be very difficult and very expensive for the Germans to defend against. They were right.

“The balloon cruising altitude was high enough that even if spotted in the daytime, it would exact a significant cost in fuel and wear and tear on the fighter aircraft that were diverted to the task of intercepting and destroying the balloons.”

Captain C. G. Banister, the director of Boom Defence, began testing options for Operation Outward. Boom Defence was an Admiralty group responsible for laying anti-ship and anti-torpedo booms to protect British harbors.

Captain Banister was a strong supporter of the use of balloons as offensive weapons. He proposed a series of trials to determine the best options for balloon size, cable details, weather conditions, and effects of safety features built into power supply lines.

The trials were conducted using surplus latex meteorological balloons (about 8’ in diameter) and the calculations from the trials helped predict that there was between a 10% and 75% chance the cables would come into contact with the intended targets: high-voltage overhead lines.

The trials showed that even if the trailing cable was severed, a balloon could still continue traveling and the remaining portion of the cable could still potentially engage power lines along the way.

Also, balloons could engage more than one power line by continuing to drift from target to target.

(Remember, 10% to 75% chance 😂 so luck was definitely a factor.)

“A balloon’s trailing wire could cause the same kind of phase-to-ground short that would occur from normal peacetime causes such as conductors breaking.”

“These resulted in tripping of circuit breakers and an inconvenient, but usually short-term, resultant loss of power. However, if the trailing wire caused a phase-to-phase event, it could be much more serious.”

The British were working off several assumptions and some known information, such as the fact that German high-voltage electric transmission systems were protected by Petersen coils, which would not tolerate phase-to-phase shorts like those that would be caused by the balloons.

They also knew that the German systems used slower-acting circuit breakers that were not designed for managing phase-to-phase shorts, like those that would be caused by the balloons.

They determined that the German design would result in the destruction of the circuit breakers and transformers, and possibly cause “catastrophic faults, such as wrecking an entire power generating station, which actually happened in 1942.”

They were not concerned about retaliation for Operation Outward, although Hitler was often inclined to retaliate. The British electrical grid had been developed with faster-acting circuit breakers that had already proven they could tolerate contact with errant barrage balloons.

“Further supporting the argument that trailing wires could be an effective weapon was the idea that since the balloons would be released in large numbers…”

“… they would be likely to cause numerous faults in the same area, thereby complicating the task of repair and further diverting valuable resources. Also, even a single balloon could cause multiple disruption events as its long wire dragged along the ground.”

Wartime shortages in England and in Germany meant that damage caused by the balloons could be more impactful than damage caused by a single bomb dropped since the necessary materials for repairs to the electrical systems were in scarce supply.

Operation Outward received its initial approval on 4 March 1942, and the first balloons launched on 20 March 1942 – just about 80 years ago.

Initially the request was to launch balloons shortly before blackout hours, but after some arguing between the different organizations involved and it was decided the balloons would launch between 10am and roughly 4pm, depending on weather.

There were several launch sites established, about 50 miles apart, along the southeastern coast of England, which were chosen for their proximity to the coast and also the availability of suitable alternate locations to use for best maximizing available winds.

Remember, these are literally balloons, with no power of their own. The conditions that made launching the balloons suitable were almost entirely weather-dependent. If the weather was particularly windy, the balloons would be “an indiscriminate, unguided weapon.”

“For the weapon to be effective, the winds had to be in the right direction to carry the balloons eastward and occur often enough to make it worth the effort.”

As with the shortage of supplies for repairs, the options for building materials were also scarce so developers had to make do with what was available.

“The Operation Outward payload consisted mainly of two small concentric canisters, the inner one filled with mineral oil and the outer one holding a spool of string and piano wire. There was a time-delay fuse attached to the outer wall.”

“As the balloon was launched, the fuse was lit at a point corresponding to the number of hours of flight desired. After several hours, when the balloon had already started to descend at a leisurely rate of 200 ft/min because of insufficient lift from leakage of hydrogen…”

“… the fuse would burn through a cord holding the trailing wire and cord in place and they would unwind, dropping down beneath the balloon.”

“The trailing cable consisted of 700 ft of 0.125” (3.2mm) diameter, 40 lb. test hemp cord secured to the balloon, and 300 ft of 0.962” (1.8mm) diameter 15-gauge steel piano wire with a breaking strength of about 1000 lbs. attached to the end of the cord.”

“The hemp cord was used to keep the unit weight and cost as low as possible.”

“At the same time that the wire was released, the stopper on the canister holding the ballast oil was pulled out, allowing the oil to slowly drip out.”

“The slow reduction in weight, plus the reduction in load due to the wire being partially supported by the ground, would keep the balloon at a more-or-less constant operating altitude of 1000 ft for the 30-mile run the Admiralty hoped to achieve.”

“The most puzzling objection to their use as an offensive weapon was that ‘attacks of this nature should not be originated from a cricketing country’ suggesting that Operation Outward somehow constituted poor sportsmanship.”

Within 5 months of the start of Operation Outward, the British were launching about 1000 balloons each day from just the main launch site. Each crew would launch about 10 balloons per hour.

“Because of ongoing pressures on obtaining male military personnel for combat duty, Outward balloon launching operations were conducted mainly by the Women’s Royal Naval Service, commonly called WRENS, under the supervision of Royal Marines and noncommissioned officers.”

“...The WRENS conducted themselves well, often working in foul weather conditions and even under enemy attack.”

Operation Outward involved 140 NCO WRENS and 7 Officer WRENS, as well as 6 Royal Navy and Royal Marine officers.

It was dangerous. There was an almost constant risk of a balloon exploding or a fire from the hydrogen used to fill them. Not to mention that some of the balloons were designed to dangle incendiaries.

Luckily, there were reportedly no Operation Outward fatalities among the crews, “although many were burned or got what was termed an ‘instant suntan.’”

“As the balloons rose in the air, some citizens in the area thought they were parachutes, triggering a panic that an invasion was underway until the local police calmed them.”

Regarding the Press and OPSEC, “in wartime Britain the government could issue stop orders, as it did in April 1942 when it demanded that all references about small drifting balloons be stopped.”

“As a result, the British general public knew very little about Operation Outward until the documents were declassified in the 1970s.”

“It was because of this secrecy order that even the people who worked on the project could only receive recognition for having caused the enemy what was termed “… damage equivalent in naval parlance to the loss of a capital ship…”

There was also little known about the German side of things regarding the operation at the time. It was learned after the war that the Germans called them “Störballons” (disturbing balloons).

Some intelligence collected during the war showed reports of “damage from the balloons from occupied France and as far east as Hungary.”

“During the war, it was hard for the British military to collect detailed information on the balloons’ effects. But there were indirect sources, because when balloons happened to stray into neutral territory and cause damage, there was strong diplomatic protest.”

“Thus, the British concluded that if the balloons were doing their job in Switzerland and Sweden, they should be working in Germany as well.”

Of the damage caused by Operation Outward, one of the worst incidents was in mid-July 1942 which resulted in the destruction of a power plant in Böhlen, near Leipzig. “The value of the material loss was estimated… at approx. $4,250,000 in 1942 currency.”

“… the evidence obtained shows that these Operation Outward attacks were a continual menace to the whole German Electric Supply system… The destruction of Böhlen alone however was an ample reward for these operations.”

In all, there were nearly 100,000 balloons launched during Operation Outward and the “result of the operation was out of all proportion to the manpower and material employed.”

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