In May 1941 a convoy of fifty merchant ships was in mid Atlantic.

It was moving slowly at 8 knots, about 9mph.

It was protected by a few small naval ships.

Suddenly one of the merchant ships exploded.

A torpedo from a U boat.

Then a second merchant ship exploded.

One of the naval ships spotted a periscope submerging.

They dropped depth charges all round where it had been.

The damaged U boat came to the surface.

The naval ships opened up with everything they had.

HMS Bulldog prepared to ram the U boat.

The U boat crew saw this and abandoned ship.

HMS Bulldog stopped.

If they had abandoned the U boat, maybe it could be captured.

HMS Bulldog lowered a rowing boat with a boarding party.

When they got to the U boat, Lt. David Balme went aboard.

He climbed up the conning tower and looked down the hatch.

He didn’t know if there was anyone still there.

He holstered his pistol and started to climb down the ladder.

He said that moment was the most terrifying of all.

He was completely defenceless, with both hands on the ladder and his back to the interior.

When he got to the bottom of the ladder he began to explore.

It was empty, so he began to strip everything off the U boat.

Maps, codebooks, logbooks, charts.

Even a strange machine that looked a bit like a typewriter.

They sent everything back to HMS Bulldog.

Then they took the U boat under tow.

After a few hours they got a message from the Admiralty.

The U boat must be sunk, now.

No one must know it had been captured.

This was absolutely critical.

So critical in fact that it became one of the biggest secrets of the war.

Actually it was the secret that won the war.

What they had captured was the Enigma machine.

Plus all the rotors and codebooks.

It was crucial that the Germans didn’t find out, because then they’d change the settings on their machines.

But if they didn’t know, the British could intercept all their secret messages about U boat positions, Luftwaffe targets, Wehrmacht movements, everything.

Which is why, for the rest of the war, ten thousand people at Bletchley Park decoded German secret messages daily.

But you may not have heard that version of the story.

You may have heard the Hollywood version.

It was called U571.

It cost $62 million to make, it took in $127 million at the box office and it won an Oscar.

It starred Mathew McConaughey, Jon Bon Jovi, Harvey Keitel, and Bill Paxton.

It was the story about how an American crew captured a U boat and the Enigma machine.

The main flaw in the Hollywood version of course, is the Enigma machine was actually captured in May 1941.


Six months before Pearl Harbour.

Six months before America even entered the war.