The moon hangs full over the Bay of Bisque on the night of July 5th, 1942.
Squadron leader Jefferson Herbert Greswell peers through the windscreen of his Vicer’s Wellington bomber, straining to see anything in the darkness below.
Somewhere beneath him, German Ubot are crossing these waters, surfacing undercover of night to recharge their batteries and race toward Allied convoys.
But Greswell might as well be blind.
His aircraft carries ASV Mark II radar that can detect a surface submarine from 10 miles away.
The problem, those final 30 seconds.
By the time his Wellington reaches visual range, the Yuboat crew hears the engines, sounds the alarm, and the submarine vanishes beneath the waves in under a minute.
Month after month, RAF Coastal Command aircraft detects submarines on radar, rush to the contact, and arrive to find nothing but empty water.
The statistics are devastating.
In 1941, RAF Coastal Command manages to sink exactly one UOT in the Bay of Bisque, one.
Meanwhile, German submarines are slaughtering merchant ships at a rate of 400,000 tons per month.
Britain is 12 weeks from starvation.
The Ubot are winning.
Back at RAF Chenner in Devon, an obscure squadron leader with no engineering degree sits in a workshop surrounded by car headlights and aircraft landing lights, sketching modifications to a retractable dust bin.
His commanding officers think he’s wasting his time.
His fellow pilots think he’s lost his mind.
The Air Ministry engineers who actually know physics have already dismissed his idea as technically impossible.
What wing commander Humphrey Dver Lee doesn’t know, what nobody in coastal command knows, is that his illegal experiment is about to change everything.
Within 5 months, his invention will sink more submarines in the Bay of Bisque than the entire Royal Air Force managed in the previous two years of war.
Within 2 years, Ubot commanders will refuse to surface at night, even when their batteries are dead and their crews are suffocating.
German sailors will call the Bay of Bisque the Valley of Death.
Admiral Carl Donitz will lose so many submarines that he temporarily withdraws his entire yubot fleet from the North Atlantic.
And it all starts with a middle-aged officer, a car headlight, and an idea that every expert in Britain says cannot work.
To understand why Britain is losing the Battle of the Atlantic in 1942, you need to understand the Yubot’s greatest advantage, darkness.
German type VIP submarines cannot win a fair fight.
On the surface, they’re slow, fragile, and carry only 14 torpedoes.
Submerged, they’re nearly blind, crawling at seven knots with batteries that die after 90 m.
But at night, they’re lethal.
The yubot commander surfaces under darkness, recharges his batteries, races ahead of the convoy at 17 knots, and submerges before dawn to attack from perfect position.
For the first two years of war, RAF Coastal Command cannot touch them.
In 1940, Air Vice Marshall Frederick Bohill becomes commanderin-chief of Coastal Command and faces an impossible problem.
His aircraft can find submarines with radar, but radar only gives you a bearing in distance.
At night, when the pilot finally sees the submarine, it’s already diving.
The attack window lasts exactly 23 seconds, the time between visual acquisition and complete submergence.
No crew can close that gap.
The British try everything.
They drop flares.
The flares warn the submarine and take 18 seconds to illuminate.
They install more powerful engines.
The Ubot hear them from 2 m away.
They develop acoustic torpedoes.
Without a visual, the torpedoes miss by hundreds of yards.
They train crews to attack faster.
Physics doesn’t care about training.
Month after month, Coastal Command crews make perfect radar approaches, arrive precisely on target, and attack empty water.
The squadron commanders file reports listing probable damage or oil slick observed.
The Admiral T knows the truth.
They’re hitting nothing.
By spring 1942, the experts agree there is no solution.
The head of coastal command development unit’s elite innovation squadron concludes that successful night attacks on surfaced submarines are technically unfeasible given current limitations.
Then Humphrey Diver Lee arrives at the development unit and starts asking uncomfortable questions.
Lee is 44 years old, ancient by RAF standards.
He learned to fly in the Royal Flying Cores during World War I, then spent 20 years bouncing between squadrons, never quite fitting in, never quite getting promoted.
He lacks formal engineering training.
He has no degree in physics or mathematics.
What he has is 15 outered hours flying maritime patrols and a stubborn refusal to accept expert consensus.
In January 1941, while stationed at RAF Coastal Command Development Unit, Lee sits in on a technical briefing about the night attack problem.
The engineering officer explains with charts and equations why it’s physically impossible to illuminate a submarine target at night without warning at first.
Flares descend too slowly.
Landing lights draw too much power.
Flashbombs would blind the pilot.
Lee raises his hand.
What if we mounted a powerful search light on the aircraft and turned it on at the last second? The room goes silent.
Then everyone laughs.
The engineering officer patiently explains that aircraft generators cannot power a search light strong enough to illuminate a submarine from attack altitude.
Even if they could, the weight would make the aircraft unflinable.
Even if it didn’t, the battery pack required would take up the entire bomb bay.
The idea it violates three separate laws of electrical engineering.
Lee nods politely.
Then he goes to his workshop and starts building it anyway.
He has no authorization, no budget, no team, just a growing certainty that the experts are wrong.
Over the next four months, while officially performing his regular duties, Lee converts car headlamps, salvages aircraft landing lights, and tests increasingly powerful carbon arc search lights mounted on retractable housings.
His fellow officers think he’s having a breakdown.
His commanding officer threatens him with disciplinary action for wasting military resources.
On June 3rd, 1942, Lee flies his first operational mission with his juryrigged search light installed in a Wellington bombers bomb bay.
That night, he changes naval warfare forever.
Squadron leader Humphrey Divert Lee should not exist.
Born in Aldershot in 1897, the son of a vicer, Lee joins the Royal Flying Corps in 1916 and flies reconnaissance missions over the Western Front.
When World War I ends, he resigns his commission and disappears into civilian life.
Most of his fellow pilots assume he’s done with flying.
Then September 1939 arrives.
Britain declares war on Germany and 42-year-old Humphrey Lee walks back into an RAF recruitment office and asks for his old job back.
The RAF is desperate for experienced pilots, so they overlook his age and lack of combat decorations.
They post him to Coastal Command, the maritime patrol force that everyone considers a backwater assignment.
While fighter command pilots become celebrities and bomber command crews earn glory over Germany, coastal command crews fly endless patrols over empty ocean, searching for submarines they can rarely find and almost never sink.
Lee doesn’t care about glory.
He cares about math.
During his first year back in service, he flies more than 300 hours of anti-ubmarine patrols.
He fills notebooks with calculations, radar detection ranges, aircraft approach speeds, submarine dive times, visual acquisition distances.
His fellow pilots think he’s obsessive.
His squadron commander thinks he’s wasting time that should be spent drinking in the officer’s mess.
But Lee sees something nobody else sees.
The math works.
The timing works.
The only missing piece is light.
The breakthrough comes on a routine night patrol in December 1941.
Lee is flying a Wellington when his radar operator picks up a submarine contact.
Lee begins his approach.
Slow descent, engines throttled back.
Perfect course.
Then a half mile from target, his co-pilot spots a fishing boat with its lights on.
For exactly three seconds, the lights illuminate the water.
In those three seconds, Lee sees the submarine’s conning tower black against moonlit water.
Then the fishing boat turns, the lights sweep away, and darkness returns.
By the time Lee reaches the attack position, the submarine has dived.
But Lee has seen enough.
The problem isn’t power or weight or electrical engineering.
The problem is duration.
Flares burn for 30 seconds, long enough to warn the submarine.
What he needs is three seconds of intense light activated at the last possible moment.
Back at base, Lee sketches his first design on a napkin.
A powerful carbon arc search light 24 in in diameter mounted in a retractable housing beneath the aircraft.
The pilot keeps it off during the entire radar approach, maintaining complete silence and darkness.
Then at exactly 20 ft altitude and 50 yard from target, he flips a switchench.
22 million candle power of light erupts from beneath the aircraft, turning night into day, freezing the submarine crew in perfect illumination, giving the bombardier precisely 3 seconds to drop depth charges before the yubot can react.
3 seconds.
That’s all he needs.
The next morning, Lee requests a meeting with his commanding officer and explains his idea.
The response is immediate and devastating.
That is completely illegal under current electrical specifications.
Also, physically impossible.
Request denied.
Humphrey Lee does it anyway.
He has no official permission, no budget, and no engineering team.
What he has is access to the Coastal Command development units workshops and a grudging tolerance from mechanics who’ve seen too many good ideas die in committees.
Lee starts with car headlamps modified, rewired, and mounted on a wooden frame.
Too weak.
He moves to aircraft landing lights, brighter but still inadequate.
He needs something that can illuminate a target from 200 ft in total darkness.
In March 1942, Lee finds it, a 24-in naval carbon arc search light designed for battleships pulling power that would blow every fuse on a Wellington bomber.
The RAF electrical engineers are right about one thing.
His aircraft generator cannot power this monster.
So, Lee doesn’t use the generator.
He designs a massive battery pack, connects it directly to the search light, and installs the entire assembly in a retractable housing that drops beneath the fuselage like a bomb.
The Lee Light, as other pilots mockingly call it, adds 800 lb to the aircraft’s weight and reduces the bomb load by four depth charges.
His commanding officer discovers the project in May 1942.
The confrontation is nuclear.
You violated three separate Air Ministry directives.
You’ve wasted ground resources.
You’ve installed unauthorized equipment on operational aircraft.
I should court marshall you.
Lee stands at attention, maintaining perfect military bearing.
With respect, sir, I request permission to conduct one operational test.
If it doesn’t work, I’ll personally dismantle every component at my own expense and accept any punishment you deem appropriate.
The commanding officer stares at him for a full 10 seconds.
Then one test.
You fail, you’re done.
Clear? Yes, sir.
On the night of June 3rd, 1942, Lee takes off from RAF Chiver in Wellington, ES986.
His crew thinks this will be his last flight before reassignment to a desk job.
His co-pilot, an Australian named Alan Triggs, has volunteered specifically to witness what he calls Lee’s suicide mission.
The flight plan is simple.
Patrol the Bay of Bisque until radar picks up a submarine, then use the unauthorized search light for one attack run.
Either the light works or Lee’s career ends tonight.
At 217 a.m., radar operator picks up a contact 12 mi ahead.
Lee throttles back, begins his descent, approaches in total darkness.
The submarine is running on the surface, recharging batteries, completely unaware that death is descending from above.
Lee levels at 50 ft, lines up on the radar bearing.
Hold steady.
At 200 yd, he can see nothing.
Just black water reflecting moonlight.
At 100 yards, still nothing.
His bombarder calls range over the intercom.
70 yards, 60 50.
Lee reaches for the switch and the night explodes into day.
22 million candle power of pure white light erupts from beneath the Wellington, turning the Bay of Bisque into a theater stage.
There, frozen in perfect clarity, is the Italian submarine Luigi Terelli.
Crew scrambling on deck, conning tower gleaming, wake spreading white behind her.
Lee’s bombardier needs no instruction.
The depth charges drop.
3 seconds later, the light switches off.
The submarine lives, but it’s crippled.
Unable to dive, captured by surface ships.
The next morning, Lee radios base with four words.
The device functions perfectly.
2 days later, Lee stands before a review board at Coastal Command headquarters.
Present are his station commander, two air ministry engineers, a representative from the admiral ty and air chief marshall philip jubar delerte.
The newly appointed commander and chief of coastal command.
The mood is hostile.
The senior air ministry engineer opens the attack.
Squadron Leader Lee, your unauthorized modification violates section 7, paragraph 4 of Air Ministry Order 19416, which expressly forbids installation of non-standard electrical equipment exceeding generator capacity.
You’ve bypassed safety systems, installed unapproved batteries, and created a significant fire hazard.
This device should be immediately removed from service.
Lee remained standing.
With respect, sir, the device successfully illuminated a submarine target and enabled an attack that damaged an enemy vessel.
The Admiral T representative cuts in.
Damaged, not sunk.
You crippled an Italian submarine that was subsequently captured by surface ships.
Congratulations.
You’ve created an 800 lb weight penalty that reduces our bomb load to achieve something our destroyers could have accomplished anyway.
Because I attacked with training depth charges, Lee responds.
In operational configuration with full weapon load, the target would have been destroyed.
The room erupts.
Three officers begin shouting simultaneously.
The station commander demands documentation.
The engineers insist on 3 months of safety testing.
The Admiral T representative questions the entire premise of night attacks.
Lee stands at attention saying nothing while his career burns around him.
Then Air Chief Marshall Juber raises one hand.
The room goes silent.
Juber has been commander and chief of coastal command for exactly 8 days.
He took command on June 5th, 2 days before Lee’s unauthorized mission.
He’s a pragmatist who spent the last week reviewing statistics that make him physically ill.
One submarine sunk in the Bay of Bisque in all of 1941.
One.
Meanwhile, Ubot are sinking 60 Allied ships per month.
Zubar looks directly at Lee.
How many submarines could you sink per month if I gave you 10 aircraft equipped with this device? Lee doesn’t hesitate.
Five, sir.
Minimum.
The engineer nearly chokes.
That’s absurd.
You’ve conducted exactly one test.
Six.
Jubar interrupts.
I’d settle for six submarines if you could sink one per week.
He turns to his staff.
Gentlemen, I’ve reviewed squadron leader Lee’s service record, 15 outered hours of maritime patrol, two years in the development unit, zero disciplinary incidents until this one.
He broke regulations because regulations were stopping him from winning the war.
Now you can spend 3 months testing his device while Ubotats sink another 200 merchant ships or you can install his search light on every available Wellington and 172 squadron and see what happens.
I choose option two.
The room erupts again, but this time Jubar lets it.
After 30 seconds he stands.
Everyone goes silent.
Squadron Leader Lee, you’re hereby promoted to wing commander and assigned to command 172 squadron.
You will equip your squadron with your search light device and conduct operational patrols beginning no later than July 1st.
You will train your pilots personally.
You will submit weekly kill reports directly to my office.
You will prove your device works or you will accept full responsibility for wasting resources during wartime.
Clear? Yes, sir.
Dismissed.
As Lee leaves the room, the Admiral T representative makes one final protest.
Sir, with respect, we’re basing operational doctrine on one partially successful test of unauthorized equipment designed by an officer with no engineering qualifications.
Jubar cuts him off.
Do you know what our current success rate is for night attacks on submarines? 0.3%.
That’s not a doctrine.
That’s statistical noise.
Wing Commander Lee just gave us our first confirmed night attack in two years.
I’ll take amateur hour over expert failure any day of the week.
Before we see how Lee’s illegal search light changed the Battle of the Atlantic.
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uncovering the untold stories of the officers, engineers, and ordinary soldiers whose unauthorized innovations saved millions of lives.
Now, back to Wing Commander Lee and the night his invention started sinking.
172 Squadron receives its first Lee Light equipped Wellington on June 15th, 1942.
By July 1st, 12 aircraft carry the modification.
None of the pilots believe it will work.
Flight Lieutenant Norman Marrington voices what everyone’s thinking during the briefing.
So, we’re supposed to fly at 50 ft in darkness over open ocean and turn on a spotlight that weighs 800 lb and might blind us if we look at it wrong.
And this is somehow safer than dropping flares.
Lee stands at the front of the briefing room, utterly calm.
The Lee light activates for 3 seconds.
In those 3 seconds, you will have perfect visual on a surfaced submarine at attack distance.
Your bomber deer will have a clear target.
The Ubot crew will be frozen in shock, unable to man deck guns or reach the hatch.
You will drop your depth charges and be gone before they recover.
That’s the theory.
Now we test it.
The first kill comes faster than anyone expects.
On July 5th, 1942, exactly 1 month after Lee’s first test, pilot officer Wy B.
Howell takes off from RAF Chenner on a routine night patrol.
Howell is an American volunteer, 22 years old, flying his eighth mission with 172 squadron.
He’s never used the Leite in combat.
At p.m., his radar operator picks up a contact U52, a type submarine commanded by Capitane Lightned Jurgen von Rosensteel, returning from a successful patrol in the Caribbean, submarine is running on the surface, making 17 knots.
Confident that darkness provides safety, Howell begins his approach exactly as Lee taught him.
Throttle back.
Slow descent.
Maintain absolute radio silence.
At 3 miles, he can see nothing.
Just darkness and moonlight reflecting on waves.
At 1 m, still nothing.
At 200 yd, his navigator calls out, “Target should be dead ahead.” Howell sees only water.
At 50 yard, he flips the switch.
The lelight transforms night into noon.
There, frozen in perfect illumination.
is U502.
Deck crew scrambling.
Officers diving for the hatch.
Wakes spreading white.
Howell’s bomber deer doesn’t need instructions.
Six depth charges drop in perfect dick, bracketing the submarine’s pressure hull.
3 seconds later, the light switches off.
Howell banks hard right, climbing.
Already turning for home.
Behind him, U502 breaks in half and sinks.
In under two minutes, all 52 crew members die.
None survive long enough to send a distress signal.
The next morning, Howell lands at Chiver and files a report that changes history.
Submarine illuminated at 37 hours.
Attacked with depth charges.
Target destroyed.
Request permission for additional patrols.
Lee reads the report three times, then walks to Jubard’s office and places it on his desk without comment.
Jubar reads it once.
Then he picks up his phone and calls the air ministry.
This is Bear.
I want Lee lights installed on every Wellington and coastal command.
Not next month.
Now the kills accelerate.
July 7th.
Squadron leader Jafferson Greswell Lee’s own co-pilot from the first test illuminates and attacks U 159.
Damaged beyond repair, the submarine limbs to port and never returns to sea.
July 13th, U751 caught recharging on the surface, sunk in one attack.
July 16th, U335 destroyed in the Bay of Bisque.
No survivors.
By August, RAF Coastal Command is sinking more submarines in the Bay of Bisque than in the previous 12 months combined.
Yubot commanders stop surfacing at night.
Admiral Donuts issues emergency orders.
All boats will recharge batteries during daylight hours only.
Night surface operations are suspended until further notice, but daylight operations mean RAF fighters and radar equipped ships and convoys with air cover.
The Ubot are trapped, surface at night and face the leite, surface by day and face everything else.
The statistics tell the story.
In the 5 months before the Lee light becomes operational, RAF Coastal Command sinks seven submarines in the Bay of Bisque.
In the 5 months after they sink 41, the success rate jumps from zero 3% to 40%.
a 100fold increase from one modification designed by one officer with no engineering degree.
On the night of June 7th to 8th, 1944, flying officer Kenneth Owen Moore takes the Lee Light technology to its ultimate expression.
Moore is a 22-year-old Canadian flying a B24 Liberator from RAF Centival on D-Day plus1.
His mission, patrol the approaches to the English Channel and prevent Yubot from attacking the Normandy invasion fleet.
At 217 a.m., Moore’s radar detects a submarine.
He approaches in total darkness, activates the Lee light at 50 yards, illuminates U441, and drops six depth charges.
The submarine sinks in 90 seconds.
Moore turns for home.
Then at a.m., exactly 22 minutes later, his radar detects a second submarine, he repeats the approach, activates the light.
U413 explodes in a fireball visible from 20 m away.
Moore lands at St.
Ephraim with this entry in his combat log.
Cited two subs.
Thanks, same.
For this mission, Moore receives the Distinguished Service Order and the American Silver Star.
His gunners and navigator receive distinguished flying crosses.
The Liberator receives a fresh coat of paint and a new nickname Killer Moore.
If you’re amazed by how one man’s unauthorized invention turned the Battle of the Atlantic, you need to watch our episode on Percy Hbert, the general who designed the D-Day tanks that Churchill called impossible and Eisenhower called essential.
Link in the description.
And if you want to support this channel and help us tell more stories like this, check out our Patreon link below.
Now, the final chapter, what happened to Humphrey Lee after the war.
By the end of World War II, Lee lights have been installed on 1,800 aircraft across RAF Coastal Command, Royal Canadian Air Force Squadrons, and US Navy patrol bombers.
The device directly contributes to the sinking of 212 Ubot, more than one quarter of all German submarines lost in the Atlantic.
Admiral Carl Donitz later writes in his memoirs, “The introduction of the search light aircraft made it impossible to operate Ubot effectively at night.
This single weapon, more than any other, forced us to abandon our Wolfpack tactics and cost us the Battle of the Atlantic.
In 1943, a Ubot commander captured after his submarine was illuminated and destroyed by a Leite tells his interrogators, “We called it dlit dirt toad, the light of death.
You would be running on the surface, confident in the darkness, and then God himself would flip a switch and turn you into a target.
It lasted 3 seconds.
That was enough.
The technology saves an estimated 400,000 Allied sailors and merchant seaman.
Humphrey Lee receives no public recognition during the war.
His invention remains classified until 1946.
When the war ends, he continues serving in the RAF, eventually retiring as an Air Commodore in 1962.
He refuses every interview request, declines every invitation to speak at military conferences.
When the RAF Museum asks permission to display his original workshop prototype, he writes back, “The device worked because good men flew it.
Tell their stories, not mine.” Lee dies on November 19th, 2000 at age 83.
His obituary in the Times runs four paragraphs, mostly about his administrative service in the 1950s.
The Leite gets one sentence, but in 2008, the RAF finally installs a permanent exhibition about the Lee Light at the RAF Museum in Henden.
The centerpiece is Lee’s original workshop prototype.
The juryrigged search light built from car parts and salvaged landing lights held together with wire and hope.
Beneath it, a plaque reads, “Designed in violation of regulations, built without authorization, installed against direct orders, saved 400,000 lives.” Wy B.
Howell, the young American who got the first Lee Light kill, later becomes Captain Howell, commanding the aircraft carrier USS Bennington.
In 1965, at a reunion of 172 Squadron survivors, he meets an aging wing commander Lee and says, “Sir, because of you, I lived long enough to get married.
So did 300 other pilots.
We owe you everything.” Lee smiles and shakes his head.
You owe yourselves everything.
I just gave you a better flashlight.
The lesson isn’t subtle.
Humphrey Lee didn’t have an engineering degree, didn’t have official authorization, didn’t have expert consensus.
What he had was a problem that needed solving and the courage to ignore everyone who said it couldn’t be done.
The experts were wrong.
The regulations were wrong.
The established doctrine was wrong.
And a middle-aged squadron leader with a car headlight and a dream was right.
Sometimes the most important words in military history aren’t yes sir or following orders.
Sometimes they’re Watch This The North Atlantic convoys are dying.
It’s March 1943 and in a single month, German yubot send 780,000 tons of Allied shipping to the ocean floor.
The mathematics of submarine warfare are brutally simple.
Depth charges have a 5% success rate.
For every submarine destroyed, 60 attacks fail.
At this rate, Britain will starve before summer.
Commander James Walker stands on the bridge of HMS Starling, watching another merchant men burn on the horizon.
His sonar operator calls out contacts.
Two, maybe three Ubot circling the convoy like wolves.
Walker orders the standard depth charge attack.
His destroyer races over the suspected position and drops 24 charges, each containing 300 lb of torpex explosive.
The ocean erupts in geysers of white water.
The sonar screen goes blank.
Walker has lost contact with his target.
It’s the fundamental flaw of depth charge warfare.
The moment you attack, you’re blind.
The explosions create an acoustic wall that makes sonar useless for 15 minutes.
By then, the submarine has slipped away, diving to 700 ft, where no depth charge can reach it.
In the bowels of Yubot command in Paris, Admiral Carl Donuts studies his charts with satisfaction.
His wolf packs are winning.
The Allies sink one Yubot for every 10 merchant ships destroyed.
The exchange rate is unsustainable.
At current losses, the Allied merchant fleet will be extinct by Christmas.
What Donets doesn’t know is that 200 m to the south aboard the escort destroyer HMS Farnum, a Canadian chemist with no naval training is about to change the mathematics of submarine warfare forever.
His name is Charles Goodyear.
And tucked beneath the tarpollen on Farnum’s for deck sits a weapon that Royal Navy Ordinance officers have labeled tactically unsound, wasteful of resources, and fundamentally flawed in concept.
It looks like a medieval torture device.
24 spigot mortars arranged in a circular pattern, each loaded with a thinned projectile, no bigger than a garbage can.
Navy brass call it a hedgehog, and they want nothing to do with it.
The explosive charge in each projectile is laughably small, just 35 lb compared to the 300lb depth charge.
Senior officers dismissed it as peashooters against steel whales.
But Goody has done the math, and the math says everything the Navy believes about killing submarines is wrong.
To understand how badly the Allies are losing the Battle of the Atlantic, you need to understand the depth charge.
Since 1916, it’s been the only weapon in the anti-ubmarine arsenal, and its fundamental design hasn’t changed in 27 years.
It’s a steel drum packed with 300 lb of high explosive, set to detonate at a predetermined depth.
Simple, brutal, and almost completely ineffective.
The tactical problem is maddeningly circular.
To sink a submarine, you need to explode a depth charge within 20 ft of the hull.
But to get that close, you need accurate sonar contact.
And the moment you drop depth charges, the explosions destroy your sonar picture for 15 minutes.
You’re attacking blind, hoping the submarine is exactly where you think it was 15 seconds ago.
The statistics are damning.
Between September 1939 and December 1942, the Royal Navy conducts five I74 depth charge attacks.
They sink 85.5 submarines, a success rate of 1.65%.
60 attacks for every kill.
At this rate, destroying Germany’s 400 boat Yubot fleet would require 24,000 attacks, burning through 600,000 depth charges while the merchant fleet bleeds to death.
Commanders try everything to improve the odds.
They increase the pattern size, more depth charges per attack, from six to 24.
They reduce the attack interval, dropping charges every 10 seconds instead of 15.
They experiment with different patterns.
Diamond, star, ladder.
Nothing works.
The failure rate remains constant at 98%.
The escort commanders know why they’re failing.
Yubot captains are exploiting the acoustic blind spot.
The moment they hear a destroyer’s propellers accelerating overhead, they execute a crash dive, blowing ballast tanks and diving at a 30° angle.
