Only one battle lasted the entire length of the Second World War.
This battle was critical for the entire European theatre, and its ebb and flow
dictated how the Allies fought everywhere else. We’re talking, of course, about the
Battle of the Atlantic — the most underrated yet most important battle of the ENTIRE war.
We couldn’t do this battle justice in a single video,
so we’ve split it into two episodes. This part will take you through the battle from
1939 up to December 1941, when the United States entered the war.
As soon as war broke out on September 3rd, 1939, the Battle of the Atlantic began. At its heart,
the battle was a blockade — the Allied and German Navies fighting to cut each other off by sea.
The battle was based on a special kind of attrition called “tonnage warfare.” This
was a deadly game, where the British raced to import the supplies they desperately
needed as well as expand their fleet, all while the Kriegsmarine hunted them down.
It might seem strange, but sneak attacks against merchant shipping were permitted under the rules
of war. The cargo ships the Kriegsmarine were hunting were called Merchantmen, and they often
carried radios to report the position of German vessels, as well as light weapons to defend
themselves. This technically made them warships, even though they were crewed by civilian sailors.
The battle went through many stages, each marked by new technologies and strategies deployed by
both sides to gain a tactical edge. Geography also played a major role and was initially advantageous
to the Allies. Before the fall of France in June 1940, the German fleet had to operate from German
waters. This meant that U-boats had to either travel through the perilous English channel,
which was thick with Allied patrols, or steam north-west through the North Sea and around
Scotland, adding weeks to the journey. This all changed when France surrendered,
opening up the Bay of Biscay to the German fleet. Now the Kriegsmarine had a safe base to launch
raids on just about ALL the shipping coming into Britain, and they exploited this to full effect.
They called it the “Happy Time” — 9 months of the most successful U-boat operations ever launched.
Silent and lethal, German Type Seven and Type Nine U-boats sank 282 ships, totalling over 1,480,000
tons, in night attacks. In this early stage of the war, Allied submarine-finding technology was
extremely limited, and the best early-warning system most ships had were their sailors' eyes.
Coordinated by encrypted radio messages, several U-boats would group up in a “wolfpack” and stalk
the waves for merchantmen. Once they had located their prey, the wolfpack would submerge and follow
the unfortunate ships until nightfall. Under the cover of darkness, the U-boats would surface and
strike one at a time. Making each torpedo count was critical, as the U-boats had few reloads.
During the perfect conditions of the Happy Time, three men gained legendary status for
their deeds in the Atlantic. U-boat captains Otto Kretschmer, Gunther Prien, and Joachim Schepke.
Fregattenkapitän Kretschmer of the Type Seven *U-99* got the nickname “silent Otto” for his use
of stealth. Kretschmer once sneaked his way into the middle of an Allied convoy before surfacing
and launching his attack, a deed so unprecedented that the Allies thought he did it by mistake!
Korvettenkapitän Prien of the Type Seven *U-47* sank over 160,000 tons of shipping, and became
a legend after sinking the British battleship *Royal Oak* while she was resupplying in port.
The attack killed the famed Admiral Henry Blagrove and shattered Royal Navy morale.
Kapitänleutnant Schepke of the Type Two *U-19* and the Type Seven *U-100* was a propaganda hero,
having sunk 34 ships for a total of 213,000 tons. For this, he received Germany’s highest
military honour, the Knight's Cross of the Iron Cross with Oak Leaves.
The success of these men didn’t seem to be enough for Kriegsmarine top brass, however.
All but one German Admiral, the submarine fleet commander Karl Donitz, believed wholeheartedly
that the Battle of the Atlantic could be won by surface actions. Donitz’s U-boat war was
seen as a sideshow, even though the submariners were sinking *serious* numbers of Allied ships.
The Kriegsmarine Admirals preferred to stick with what they knew, committing Germany’s four
modern battleships, two obsolete battleships, and six heavy cruisers to surface raiding operations.
They also threw in 13 commerce raiders, which were civilian ships decked out
with weapons and disguised so they could sneak up on Allied convoys.
The U-boat Happy Time coincided with the surface raiders’ greatest successes. The most successful
was the heavy cruiser *Admiral Scheer*, which decimated an Allied convoy on November 5th, 1940.
The *Admiral Scheer* sank five merchantmen with her six-inch and 11-inch guns before the convoy
scattered. The rest of the merchantmen were saved by the heroic sacrifice of the lightly-armed
escort ship HMS *Jervis Bay*, which charged the German heavy cruiser, creating a distraction.
The greatest Kriegsmarine surface raid was also the last.
The legendary battleship *Bismarck* set out with the Heavy Cruiser *Prinz Eugen* on May 18th,
1940. They were going after merchant shipping, but the British HMS *Prince of Wales* and HMS *Hood*
intercepted them off the Icelandic coast. The British fired first... and missed. *Bismarck’s*
devastating return-fire smashed into *Hood* and blew apart her aft ammunition storeroom. *Hood*
exploded and went to the bottom within three minutes, taking her crew of 1,418 with her.
The battle-damaged *Bismarck* set a course to occupied France for repairs.
She never made it. Crippled by a carrier airstrike, the mighty battleship was pounded
to oblivion by two British battleships and an entire flotilla of destroyers.
The sinking of the *Bismarck* represented a huge propaganda victory for the Allies and finally
demonstrated to the Kriegsmarine Admirals that surface raiders just couldn’t match the U-boats.
The sinking of the *Bismarck* on May 27th, 1940,
was the end of Germany’s surface battles in the Atlantic.
What took Germany the loss of their best ship to realise,
the Allies had recognised right from the start of the war — that U-boats were their most
serious threat. The British Prime Minister Winston Churchill agreed, stating in his memoirs:
“The only thing that ever really frightened me during the war was the U-boat peril.”
In the face of the U-boat peril, Britain and her allies pulled together.
From October 1940, all merchant shipping across the Atlantic was put under military control.
Merchantmen were grouped up in large convoys with several escorting destroyers and corvettes,
with some convoys growing to 50-plus ships. Canadian shipbuilding was also
kicked into fifth gear, making many more merchantmen and escorts available.
Large convoys with many escorts were far tougher prey than the smaller,
lightly-armed convoys used previously. This alone would have been enough to keep wolfpacks away,
but the Allies had another invention: a short-wave radar set. Designated the Type-271,
this radar could detect a surfaced U-boat five kilometres away. On a dark night,
having a radar in the convoy meant ships had early warning of an impending U-boat attack.
The Allies realised the impact on convoy survivability the Type-271 radar was having and
decided to put their geniuses to work improving it. The result was HF/DF, known as “Huff-Duff.”
Instead of emitting radio waves like the Type-271, Huff-Duff listened to radio messages sent
between the U-boats of a wolfpack and told the operator the direction those signals came from.
Donitz liked to receive constant updates from his U-boats to coordinate their actions in
the wider battle, but this gave away the silent hunters' most precious advantage.
Every time they sent Donitz a report, they were broadcasting their position to the Allies.
Huff-Duff couldn’t read messages; it only indicated which direction they came from.
In fact, during the early part of the war, British command believed the German Naval Code,
nicknamed Enigma, was utterly unbreakable.
They were proven wrong by the mathematical genius and computer pioneer Alan Turing.
With very few clues, Turing and his team at Bletchley Park used mathematical modelling and
statistics to figure out how the Enigma machine worked. Turing then combined this model with
codebooks captured from a sinking U-boat to invent a system for decoding Kriegsmarine radio messages.
Still not satisfied, Turing then built a computer to speed up the decryption process.
The upshot of all this “big-brain time” work was that from summer 1941 onwards, the Allies
could read the Kriegsmarine's radio signals. Every time a U-boat reported its position,
as Donitz requested they constantly did, the Allies knew where it was. This was an absolute
gamechanger for the Battle of the Atlantic, and the entire war in Europe.
. Every time a U-boat reported its position, as Donitz requested they constantly did, the
Allies knew where it was. This was an absolute gamechanger for the Battle of the Atlantic,
and the entire war in Europe.