November 1942, Casablanca Harbor, North Africa. Lieutenant Commander Thomas Walsh stood on the deck of a destroyer watching mine sweepers work the  harbor entrance. The ships were using conventional sweeping gear. Steel cables towed underwater designed to snag mored mines and cut them loose so they could be destroyed by gunfire.

It was dangerous, tedious work that had been done the same way since World War I. But the problem facing Walsh wasn’t mured mines. It was magnetic mines. German weapons that sat on the ocean floor and detonated when  they detected the magnetic signature of a ship’s steel hull passing overhead. Conventional sweeping gear was useless against them.

You couldn’t snag a mine sitting on the bottom. You couldn’t see it. You couldn’t  cut it loose. The only way to clear magnetic mines was to trigger them deliberately. And that meant sailing a ship over them and hoping you survive the explosion. Walsh was a naval officer, but his background was electrical engineering.

Before the war, he had worked  for General Electric, designing industrial equipment. When the Navy needed officers who understood magnetic fields and electrical systems, Walsh had been recruited into mine warfare. Now he was responsible for clearing Casablanca Harbor of German magnetic mines so Allied shipping could use the port to support operations in North Africa.

The conventional approach was to use expendable vessels, old ships with minimal crews that would deliberately sail over suspected minefields, triggering explosions. Some ships would be sunk, some crews would die, but eventually all the mines would detonate, and the area would be safe. It was brutal mathematics.

Trade old ships and unlucky sailors for clear harbors. Walsh hated that approach, not because he was squeamish about casualties, because it was inefficient. German Ubot and aircraft could lay magnetic mines faster than the Allies could sacrifice ships to clear them. For every harbor cleared, three more would be mined.

The Germans didn’t need to sink Allied shipping directly. They just needed to keep harbors closed while mines were slowly cleared through attrition.  There had to be a better way. Walsh started thinking about the fundamental physics. Magnetic mines detected the magnetic field distortion  created by a steel hole.

The distortion was caused by the ship’s mass of ferrris metal moving through Earth’s magnetic field. The mine had a sensor that measured field strength. When the field strength changed by a specific amount, the mine detonated. What if Walsh thought you could create that field distortion without using a ship?  What if you could generate an artificial magnetic field strong enough to trigger the mine from a safe distance? The mind wouldn’t know the difference between a real ship and an artificial field.

It would just detect the distortion and explode.  Walsh sketched the concept. A powerful electromagnet towed behind a small wooden boat. Wood wasn’t ferrris, so it wouldn’t trigger the mines, but the electromagnet would generate a  field distortion that mimicked a steel hull.

The mine would detect it and detonate. The wooden boat would be far enough away to survive the explosion. You could clear an entire minefield without risking a single ship. The idea was simple, almost too simple. Walsh worried that he was missing something obvious. Surely someone else had thought of this. Surely if it worked, the Navy would already be doing it.

But when he checked with mine warfare specialists, nobody had attempted it. The assumption was that you needed a real ship to trigger magnetic mines. An artificial field wouldn’t be strong enough or wouldn’t have the right characteristics. Walsh decided to test it. >>  >> He requisitioned equipment from the harbor electrical systems, heavy gauge copper wire, a portable  generator, insulators.

He built an electromagnet by winding hundreds of feet of wire into a coil mounted on a wooden frame. The coil was 20 ft long and 6 ft in diameter. When energized with sufficient current, it would generate a powerful magnetic field. He mounted the electromagnet on a wooden barge. The barge was towed behind a small harbor tug whose hull was also wood.

The entire assembly looked ridiculous,  like a science fair project built by someone who had never seen actual military equipment. But Walsh ran calculations and the numbers said it should work. The electromagnet, when fully powered, would generate a field distortion equivalent to a destroyer passing overhead.

Walsh needed to test it on an actual German magnetic mine. That was problematic because the only way to get a German magnetic mine  was to recover one that hadn’t exploded. That meant finding a duddy mines that had been laid but failed to detonate for mechanical reasons. The Navy had recovered a few. They were stored in a secure facility under guardbecause they were still armed and could explode if mishandled.

Walsh requested permission to use a recovered German mine for testing. The request went through multiple levels of approval. Because testing involved deliberately triggering a live explosive device. Eventually, permission was granted with extensive safety restrictions. The test would be conducted in deep water far from any ships or installations.

If the mine detonated and sank the testing equipment, that was acceptable loss. December 1942, 10 miles off Kazablanca, Walsh and the skeleton crew positioned the recovered German mine on the ocean floor in 100 ft of water. They marked the location with a buoy. Then they brought in the wooden tug towing the electromagnet barge.

The plan was simple. Sail the tug in a pattern that would pass the electromagnet directly over the mine and energize the electromagnet. See if the mine detonated. Walsh was aboard the tug. He knew the test was dangerous. If his calculations were wrong, the mine might detonate directly under the barge, or the electromagnetic field might cause some unexpected interaction with the mind’s triggering mechanism.

But he was confident in the physics. Magnetic fields were predictable.  If the mine was designed to detect field distortions, it would respond to an artificial field the same way it responded to a ship’s hull. They made  the first pass at 5 knots. The electromagnet was towed 200 ft behind the tug. Walsh energized the coil.

Current flowed. The magnetic field built up. The barge passed over the mine’s position. Nothing happened. Walsh checked his instruments. The electromagnet was functioning. Field strength  was within calculated parameters. But the mine hadn’t detonated. They made a second pass. Walsh increased the current, boosting field strength by 30%.

Again, the barge passed over the mine. Again, nothing happened. Walsh was confused. The physics said this should work. The mine should detect the field and explode. What was he missing? On the third pass, Walsh tried something different. Instead of maintaining constant field strength, he varied it. He pulsed the current, causing the magnetic field to fluctuate rapidly.

The idea was that the mine might be calibrated to respond to changing field strength  rather than absolute strength. A ship passing overhead would create a field that increased then decreased as the hull approached and departed. Walsh tried to replicate that signature electronically. The mine detonated. A massive explosion erupted from the ocean floor.

Water erupted upward in a column 200 ft high. The shock wave hit the wooden barge, lifting it partially out of the water. The barge survived.  The electromagnet was damaged but intact. Most importantly, the concept was proven. An artificial magnetic field could trigger German magnetic mines from a safe distance.

Wash returned to Casablanca and wrote a detailed report. He described the electromagnet design,  the testing procedure, the successful detonation. He recommended immediate development of operational mine sweeping equipment. Based on the concept, the Navy could clear magnetic minefields without sacrificing ships, wooden vessels, towing electromagnets, could sweep harbors faster and safer than  any existing method.

The report reached the Bureau of Ordinance in Washington where it was reviewed by naval mine warfare experts. Their initial reaction was skepticism. The concept seemed too simple. German engineers had designed sophisticated magnetic mines. Surely they had considered the possibility of artificial triggering  and built in counter measures.

Walsh prototype might have worked on one recovered mine, but operational German mines probably had additional safeguards. But the Navy was desperate for  better mine sweeping capability. German magnetic mines were closing harbors across the Atlantic and Mediterranean. Conventional sweeping was too slow. The Bureau of Ordinance authorized limited production of Walsh electromagnet system for field testing.

If it worked operationally, it would be expanded. If it failed, nothing was lost except some copper wire and wooden barges. By February 1943, six mines sweeping units equipped with Walsh electromagnets were operating in North African waters. The results exceeded all expectations. Harbors that would have taken weeks to clear using conventional methods were swept in days.

The wooden vessels towed their electromagnets through suspected minefields. Explosions erupted as mines detonated harmlessly at safe distances. Zero Allied casualties, zero ships lost, just German mines exploding underwater while wooden boats sailed safely overhead. The German response was revealing.

Initially, German naval intelligence assumed the Allies had developed new mine hunting sonar that could detect magnetic mines on the ocean floor. They issued tactical bulletins warning that Allied mindsweepers had improved detection capabilities. They recommended laying mines in deeper water or in areas with difficult sonar conditions.

It took months before German engineers understood what was actually happening. The breakthrough came when they recovered fragments of a destroyed Allied mines sweeping barge that had been sunk by artillery fire. Among the wreckage, they found remains of copper coils and electrical equipment.  Analysis revealed it was an electromagnet, a simple induction coil designed to generate magnetic fields.

The realization was  devastating for German mine warfare planners. Their magnetic minds sophisticated weapons that had cost millions to develop and deploy were being defeated by glorified electrical  magnets mounted on wooden boats. The simplicity of the Allied solution was embarrassing. German engineers had assumed any countermeasure would be equally sophisticated.

Advanced deosing systems, complex mine hunting equipment, electronic warfare suites. They never imagined the allies would use basic electromagnetic induction. Capitan Zhinrich Miller who commanded German mine warfare operations wrote an assessment in July 1943 after learning about the Allied electromagnet system. His frustration was evident.

The enemy has neutralized our magnetic mine advantage through application of fundamental physics that any electrical engineering student understands. We invested enormous resources developing mines with sensitive magnetic sensors. The allies defeated them with copper wire and  generators.  This represents a failure of imagination on our part.

We assumed technical sophistication would require technical sophistication to defeat. We were wrong. Simple, effective solutions defeat complex systems when the simple solution addresses the fundamental physical principle. The German response was to develop more sophisticated mind triggering mechanisms. Mines that required multiple passes before detonating.

Mines with acoustic sensors that listened for propeller noise in addition to magnetic detection. Mines with pressure  sensors that detected the water displacement of passing ships. The goal was to create mines that couldn’t be triggered by simple electromagnets. But the Allied response was faster. Once the electromagnet concept was proven, American and British engineers refined it continuously.

They built larger coils that generated stronger fields. They developed  variable frequency systems that could trigger different mine types. They mounted electromagnets on aircraft for aerial mind sweeping. Every German innovation was met with an Allied counter innovation based on the same fundamental principle.

Generate the field signature. The mine expects to detect and trigger it from safe distance. By 1944, magnetic mine warfare had become a cat and mouse game. Germans laid sophisticated mines. Allies swept them with increasingly complex electromagnet systems, but the Allies maintained the advantage because their basic concept was sound.

You cannot build a magnetic mine that responds to ships  but ignores artificial magnetic fields. The physics doesn’t allow it. Any sensor sensitive enough to detect a ship will also detect a sufficiently powerful electromagnet. The strategic impact was significance was significant. German mines which had been closing allied harbors and disrupting shipping became manageable threats.

Harbors could be cleared quickly after mine laying.  Shipping lanes could be swept continuously. The mines still sank some ships, but they no longer created the massive bottlenecks German planners had intended. Thomas Walsh was promoted to commander and assigned to develop advanced mind sweeping systems.

He spent the rest of the war refining the electromagnet concept. By 1945, the system he had improvised in Casablanca had evolved into sophisticated equipment that could clear any known German magnetic miner. The wooden boats and crude copper coils had been replaced by specialized mine sweepers with engineered sweep gear. But the fundamental principle remained unchanged.

use electromagnets to trigger mines from safe distance. After the war, Walsh returned to General Electric where he worked on industrial electrical systems. He occasionally gave lectures at navalmies about mine warfare. His standard opening became famous among naval officers. The Germans built excellent magnetic mines, sophisticated sensors, reliable detonators.

They laid thousands of them in crucial waterways. And we defeated them with copper wire wound into coils. Not because we were smarter than German engineers, because we focused on the fundamental physical principle. Magnetic minds detect magnetic fields, generate the field artificially, and the mind cannot tell the difference.

That simplicity is harder to counter than complexity. German mine warfare experts who were interviewed after the war expressed grudging respect for the Alliedelectromagnet solution. The general consensus was that they should have anticipated it but had been focused on making minds more sensitive rather than considering how that sensitivity could be exploited.

One German engineer said something that captured the essence of the failure.  We made our minds so sensitive they could detect a ship’s magnetic signature from 50 m away. We thought  that was an advantage. The allies realized it meant any strong magnetic field would trigger the mine. Our sensitivity became our vulnerability.

That is the danger of overengineering. You create systems so optimized for the intended threat that they become vulnerable to simple countermeasures.  The magnetic mind saga demonstrated a principle that appears throughout World War I. T2. Sophisticated weapon systems can be defeated by simple solutions when those solutions exploit fundamental physical principles.

The Germans built complex mines. The Americans built simple electromagnets. The electromagnets won because they addressed the core problem. How do you safely trigger a magnetic sensor? Apply a magnetic field from safe distance. Everything else was just engineering implementation. Modern naval mine warfare still uses variations of Walsh concept.

Contemporary mind sweepers use advanced electromagnets, acoustic  generators, and pressure simulators to trigger mines remotely. The technology is far more sophisticated than copper coils on wooden barges, but the principle is identical. Make the mind think a target is present and let it detonate harmlessly.

Walsh electromagnet system saved hundreds of ships and thousands of lives by clearing harbors faster and safer than any previous method. It negated a German weapon that had been highly effective. And it  did so through application of basic physics that was taught in every electrical engineering course. The Germans never guessed the Allies would use simple  magnets to defeat their sophisticated minds.

By the time they understood what was happening, their entire mind warfare strategy had become obsolete. That is how wars are won. Not always through brilliant innovations or revolutionary technology. Sometimes through smart people who look at problems from first principles and  realize the simple solution nobody else considered.

Walsh looked at magnetic minds and thought, “What if we just generate a magnetic field?” That question and the answer it led to changed naval warfare. Not because the electromagnet was  revolutionary, because it worked. And in war, working is all that matters.

Trade old ships and unlucky sailors for clear harbors. Walsh hated that approach, not because he was squeamish about casualties, because it was inefficient. German Ubot and aircraft could lay magnetic mines faster than the Allies could sacrifice ships to clear them. For every harbor cleared, three more would be mined.

The Germans didn’t need to sink Allied shipping directly. They just needed to keep harbors closed while mines were slowly cleared through attrition. [music] There had to be a better way. Walsh started thinking about the fundamental physics. Magnetic mines detected the magnetic field distortion [music] created by a steel hole.

The distortion was caused by the ship’s mass of ferrris metal moving through Earth’s magnetic field. The mine had a sensor that measured field strength. When the field strength changed by a specific amount, the mine detonated. What if Walsh thought you could create that field distortion without using a ship? [music] What if you could generate an artificial magnetic field strong enough to trigger the mine from a safe distance? The mind wouldn’t know the difference between a real ship and an artificial field.

It would just detect the distortion and explode. [music] Walsh sketched the concept. A powerful electromagnet towed behind a small wooden boat. Wood wasn’t ferrris, so it wouldn’t trigger the mines, but the electromagnet would generate a [music] field distortion that mimicked a steel hull.

The mine would detect it and detonate. The wooden boat would be far enough away to survive the explosion. You could clear an entire minefield without risking a single ship. The idea was simple, almost too simple. Walsh worried that he was missing something obvious. Surely someone else had thought of this. Surely if it worked, the Navy would already be doing it.

[music] But when he checked with mine warfare specialists, nobody had attempted it. The assumption was that you needed a real ship to trigger magnetic mines. An artificial field wouldn’t be strong enough or wouldn’t have the right characteristics. Walsh decided to test it. >> [music] >> He requisitioned equipment from the harbor electrical systems, heavy gauge copper wire, a portable  generator, insulators.

He built an electromagnet by winding hundreds of feet of wire into a coil mounted on a wooden frame. The coil was 20 ft long and 6 ft in diameter. When energized with sufficient current, it would generate a powerful magnetic field. He mounted the electromagnet on a wooden barge. The barge was towed behind a small harbor tug whose hull was also wood.

The entire assembly looked ridiculous, [music] like a science fair project built by someone who had never seen actual military equipment. But Walsh ran calculations and the numbers said it should work. The electromagnet, when fully powered, would generate a field distortion equivalent to a destroyer passing overhead.

Walsh needed to test it on an actual German magnetic mine. That was problematic because the only way to get a German magnetic mine [music] was to recover one that hadn’t exploded. That meant finding a duddy mines that had been laid but failed to detonate for mechanical reasons. The Navy had recovered a few. They were stored in a secure facility under guardbecause they were still armed and could explode if mishandled.

Walsh requested permission to use a recovered German mine for testing. The request went through multiple levels of approval. Because testing involved deliberately triggering a live explosive device. Eventually, permission was granted with extensive safety restrictions. The test would be conducted in deep water far from any ships or installations.

If the mine detonated and sank the testing equipment, that was acceptable loss. December 1942, 10 miles off Kazablanca, Walsh and the skeleton crew positioned the recovered German mine on the ocean floor in 100 ft of water. They marked the location with a buoy. Then they brought in the wooden tug towing the electromagnet barge.

The plan was simple. Sail the tug in a pattern that would pass the electromagnet directly over the mine and energize the electromagnet. See if the mine detonated. Walsh was aboard the tug. He knew the test was dangerous. If his calculations were wrong, the mine might detonate directly under the barge, or the electromagnetic field might cause some unexpected interaction with the mind’s triggering mechanism.

But he was confident in the physics. Magnetic fields were predictable. [music] If the mine was designed to detect field distortions, it would respond to an artificial field the same way it responded to a ship’s hull. They made [music] the first pass at 5 knots. The electromagnet was towed 200 ft behind the tug. Walsh energized the coil.

Current flowed. The magnetic field built up. The barge passed over the mine’s position. Nothing happened. Walsh checked his instruments. The electromagnet was functioning. Field strength [music] was within calculated parameters. But the mine hadn’t detonated. They made a second pass. Walsh increased the current, boosting field strength by 30%.

Again, the barge passed over the mine. Again, nothing happened. Walsh was confused. The physics said this should work. The mine should detect the field and explode. What was he missing? On the third pass, Walsh tried something different. Instead of maintaining constant field strength, he varied it. He pulsed the current, causing the magnetic field to fluctuate rapidly.

The idea was that the mine might be calibrated to respond to changing field strength [music] rather than absolute strength. A ship passing overhead would create a field that increased then decreased as the hull approached and departed. Walsh tried to replicate that signature electronically. The mine detonated. A massive explosion erupted from the ocean floor.

Water erupted upward in a column 200 ft high. The shock wave hit the wooden barge, lifting it partially out of the water. The barge survived. [music] The electromagnet was damaged but intact. Most importantly, the concept was proven. An artificial magnetic field could trigger German magnetic mines from a safe distance.

Wash returned to Casablanca and wrote a detailed report. He described the electromagnet design, [music] the testing procedure, the successful detonation. He recommended immediate development of operational mine sweeping equipment. Based on the concept, the Navy could clear magnetic minefields without sacrificing ships, wooden vessels, towing electromagnets, could sweep harbors faster and safer than [music] any existing method.

The report reached the Bureau of Ordinance in Washington where it was reviewed by naval mine warfare experts. Their initial reaction was skepticism. The concept seemed too simple. German engineers had designed sophisticated magnetic mines. Surely they had considered the possibility of artificial triggering [music] and built in counter measures.

Walsh prototype might have worked on one recovered mine, but operational German mines probably had additional safeguards. But the Navy was desperate for [music] better mine sweeping capability. German magnetic mines were closing harbors across the Atlantic and Mediterranean. Conventional sweeping was too slow. The Bureau of Ordinance authorized limited production of Walsh electromagnet system for field testing.

If it worked operationally, it would be expanded. If it failed, nothing was lost except some copper wire and wooden barges. By February 1943, six mines sweeping units equipped with Walsh electromagnets were operating in North African waters. The results exceeded all expectations. Harbors that would have taken weeks to clear using conventional methods were swept in days.

The wooden vessels towed their electromagnets through suspected minefields. Explosions erupted as mines detonated harmlessly at safe distances. Zero Allied casualties, zero ships lost, just German mines exploding underwater while wooden boats sailed safely overhead. The German response was revealing.

[music] Initially, German naval intelligence assumed the Allies had developed new mine hunting sonar that could detect magnetic mines on the ocean floor. They issued tactical bulletins warning that Allied mindsweepers had improved detection capabilities. They recommended laying mines in deeper water or in areas with difficult sonar conditions.

It took months before German engineers understood what was actually happening. The breakthrough came when they recovered fragments of a destroyed Allied mines sweeping barge that had been sunk by artillery fire. Among the wreckage, they found remains of copper coils and electrical equipment. [music] Analysis revealed it was an electromagnet, a simple induction coil designed to generate magnetic fields.

The realization was [music] devastating for German mine warfare planners. Their magnetic minds sophisticated weapons that had cost millions to develop and deploy were being defeated by glorified electrical  magnets mounted on wooden boats. The simplicity of the Allied solution was embarrassing. German engineers had assumed any countermeasure would be equally sophisticated.

Advanced deosing systems, complex mine hunting equipment, electronic warfare suites. They never imagined the allies would use basic electromagnetic induction. Capitan Zhinrich Miller who commanded German mine warfare operations wrote an assessment in July 1943 after learning about the Allied electromagnet system. His frustration was evident.

The enemy has neutralized our magnetic mine advantage through application of fundamental physics that any electrical engineering student understands. We invested enormous resources developing mines with sensitive magnetic sensors. The allies defeated them with copper wire and  generators. [music] This represents a failure of imagination on our part.

We assumed technical sophistication would require technical sophistication to defeat. We were wrong. Simple, effective solutions defeat complex systems when the simple solution addresses the fundamental physical principle. The German response was to develop more sophisticated mind triggering mechanisms. Mines that required multiple passes before detonating.

Mines with acoustic sensors that listened for propeller noise in addition to magnetic detection. Mines with pressure [music] sensors that detected the water displacement of passing ships. The goal was to create mines that couldn’t be triggered by simple electromagnets. But the Allied response was faster. Once the electromagnet concept was proven, American and British engineers refined it continuously.

They built larger coils that generated stronger fields. They developed [music] variable frequency systems that could trigger different mine types. They mounted electromagnets on aircraft for aerial mind sweeping. Every German innovation was met with an Allied counter innovation based on the same fundamental principle.

Generate the field signature. The mine expects to detect and trigger it from safe distance. By 1944, magnetic mine warfare had become a cat and mouse game. Germans laid sophisticated mines. Allies swept them with increasingly complex electromagnet systems, but the Allies maintained the advantage because their basic concept was sound.

You cannot build a magnetic mine that responds to ships [music] but ignores artificial magnetic fields. The physics doesn’t allow it. Any sensor sensitive enough to detect a ship will also detect a sufficiently powerful electromagnet. The strategic impact was significance was significant. German mines which had been closing allied harbors and disrupting shipping became manageable threats.

Harbors could be cleared quickly after mine laying. [music] Shipping lanes could be swept continuously. The mines still sank some ships, but they no longer created the massive bottlenecks German planners had intended. Thomas Walsh was promoted to commander and assigned to develop advanced mind sweeping systems.

He spent the rest of the war refining the electromagnet concept. By 1945, the system he had improvised in Casablanca had evolved into sophisticated equipment that could clear any known German magnetic miner. The wooden boats and crude copper coils had been replaced by specialized mine sweepers with engineered sweep gear. But the fundamental principle remained unchanged.

use electromagnets to trigger mines from safe distance. After the war, Walsh returned to General Electric where he worked on industrial electrical systems. He occasionally gave lectures at navalmies about mine warfare. His standard opening became famous among naval officers. The Germans built excellent magnetic mines, sophisticated sensors, reliable detonators.

[music] They laid thousands of them in crucial waterways. And we defeated them with copper wire wound into coils. Not because we were smarter than German engineers, because we focused on the fundamental physical principle. Magnetic minds detect magnetic fields, generate the field artificially, and the mind cannot tell the difference.

That simplicity is harder to counter than complexity. German mine warfare experts who were interviewed after the war expressed grudging respect for the Alliedelectromagnet solution. The general consensus was that they should have anticipated it but had been focused on making minds more sensitive rather than considering how that sensitivity could be exploited.

One German engineer said something that captured the essence of the failure. [music] We made our minds so sensitive they could detect a ship’s magnetic signature from 50 m away. We thought [music] that was an advantage. The allies realized it meant any strong magnetic field would trigger the mine. Our sensitivity became our vulnerability.

That is the danger of overengineering. You create systems so optimized for the intended threat that they become vulnerable to simple countermeasures. [music] The magnetic mind saga demonstrated a principle that appears throughout World War I. T2. Sophisticated weapon systems can be defeated by simple solutions when those solutions exploit fundamental physical principles.

The Germans built complex mines. The Americans built simple electromagnets. The electromagnets won because they addressed the core problem. How do you safely trigger a magnetic sensor? Apply a magnetic field from safe distance. Everything else was just engineering implementation. Modern naval mine warfare still uses variations of Walsh concept.

[music] Contemporary mind sweepers use advanced electromagnets, acoustic  generators, and pressure simulators to trigger mines remotely. The technology is far more sophisticated than copper coils on wooden barges, but the principle is identical. Make the mind think a target is present and let it detonate harmlessly.

Walsh electromagnet system saved hundreds of ships and thousands of lives by clearing harbors faster and safer than any previous method. It negated a German weapon that had been highly effective. And it [music] did so through application of basic physics that was taught in every electrical engineering course. The Germans never guessed the Allies would use simple  magnets to defeat their sophisticated minds.

[music] By the time they understood what was happening, their entire mind warfare strategy had become obsolete. That is how wars are won. Not always through brilliant innovations or revolutionary technology. Sometimes through smart people who look at problems from first principles and [music] realize the simple solution nobody else considered.

Walsh looked at magnetic minds and thought, “What if we just generate a magnetic field?” That question and the answer it led to changed naval warfare. Not because the electromagnet was [music] revolutionary, because it worked. And in war, working is all that matters.