Gathering intelligence proved to be the key factor in the battle of the Atlantic.  It enabled the prediction of the location of the menacing submarines enabling the rerouting of convoys away from danger.  For the vulnerable merchant seaman carrying vital supplies both for the war effort and the nation this was essential to survive.  

 

In fact, this was not something new to WW2, intelligence gathering, and code deciphering had also played a major part in WW1 (centred around room 40), but this was not just limited to Britain but many other countries to.  In fact, Poland had managed to reproduce the enigma machine and read some German messages prior to WW2 and their work was a key factor going forward into the war perhaps influencing the great minds of Turing and Welchman (amongst many others) and their work on deciphering the Enigma.  Incidentally a common trait across all these intelligent and mathematical minds seems to have been a love of chess.

 

Other key members of the code breaking at Bletchley (although there were many more):

 

•Edward Travis Operational Head from 1942 onwards

•Harry Hinsley solved German intercepts

•Hugh Alexander head of the cryptanalyst of German naval messages

•Gordan Welchman whose device accelerated cryptanalysis

•Alan Turing head of hut 8 decrypting naval enigma codes

 

Turing was assigned hut 8 at Bletchley responsible for the naval side of enigma deciphering, the German naval use of the enigma differed to that of the army or Luftwaffe being that it was perhaps more secure.  The Germans also used water soluble ink on documents as an additional security mechanism.  Turing was inspirational in the bombe, the machine that tested for possible enigma solutions which in turn resulted in the first computer to built at Bletchley with the heavy involvement of all codebreakers.

 

 

© IWM (MH 27178)

 

Conel Hugh O’Donel Alexander, called Hugh was an inspirational member of Turing's team in fact his chief assistant.  Many other high intellectuals were gathered assisting both Turing and Welchman but great minds also needed a touch of good fortune to help a big break through come together.

 

Most people are familiar with the machine named the Enigma and are aware that it was used to encipher and decipher data in order that messages could be sent securely.  The enciphered data was sent via radio normally in morse code in the case of submarines usually at periscope depth (around 40 feet down).  The enigma machine was created by Arthur Scherbius.  The Germans put great faith in this machine and the naval communications including those from U-boats were therefore made through it.  As Donitz (German admiral who eventually succeeded Hitler for a short period) insisted on constant communication on all operational matters was to go through him, breaking the code would be greatly beneficial to the allies.

 

Also, most people are aware of the work at Bletchley Park which helped decipher these codes, but there of course is a bigger picture and lots of parties came together in order to make this all work and help win the battle of the Atlantic.

 

The Germans relied heavily on weather ships in order to plan bombings on the UK and to plan for various battles.  By their nature these ships and subs which were also required to give weather reports and were out on patrol for lengthy periods which therefore meant they carried long term enigma codes and much valued intel.  It came to the attention of Harry Hinsley in hut 4 (naval section) at Bletchley Park that these would therefore be a valuable source of intel and he founded the idea of capturing the keying books which held the enigma codes from German weather ships.

 

The start of the breakthrough

 

Although there had been several instances of vital intelligence being seized prior to this event (please see table of key events) the lack of enigma machine was causing issues.

 

With mounting losses at the hands of the U-boats and at that time an inability to replace ships at the rate they were being lost, a series of key events were about to unfold that would undoubtedly have a great impact on the course of the war.

 

 

Capture of the Enigma

 
Little did convoy OB 318 and Escort 3 Commander Joe Baker-Cresswell on HMS Bulldog (destroyer) know but they were then not only traversing the dangerous open seas, but about to be etched in into the pages of history for evermore.  

U-94 was the first sub to attack the convoy, and after creeping between the convoy columns torpedoed and sunk the British steamer Ixion and the Norwegian Eastern Star before diving deep into the murky waters running the gauntlet between the various depth charges dropped in retribution by the escort.  With slight damage the U-boat slipped away making its escape but that was not the last the convoy would see of U-boats.
 
U-110 commanded by Lemp (whose actions earlier in the war sinking the Athenia arguable the catalyst for the Atlantic battle) was prowling and was looking for an opportunity to use the classic technique of slipping in between the columns of the convoy and causing carnage.
 
Joe's escort was due to leave the convoy on the day when Lemp attacked the Esmond, this would be the start of some very historic moments that would change the course of the war in the Atlantic.  His escort made hast in pursuing U-110 dropping deadly depth charges.
 
Taking out the electronics of the sub it was in peril, leading it to eventually having to surface with the crew onboard having to make their escape without paying attention to protecting the secrets that were held in the sub.
 
The boarding party was led by sub lieutenant David Balme from the Bulldog and with many of the subs crew already in the sea and armed with pistols, rifles and grenades and gas masks for safety they went forward with gusto to their mission.
 
In fact, they discovered that all the crew had fled the sub and were in the process of being rescued (by HMS Broadway and Aubretia) obscuring them from the events that were now proceeding in gathering intel, in fact this is a vital and critical point as it meant no one knew what was about to be discovered.
 
They battled to retain the vital intel in their clasp as wave upon wave hit the stricken sub.
 
Piece by piece this valuable haul was passed down a chain to the recovery vessels (broadways whaler).  Then the biggest bounty of all down in the radio room bolted to a table was what they first thought was a typewriter, but this was no typewriter it was almost like gold it was what Bletchley and all that worked there had been waiting for, finally they had the enigma machine.
 
Although an attempt to tow the sub back to base was made this was a step too far and proved impossible.   However, the yield was still great and so vital.  Combined with all the proceeding events that had led to this, it was a pinnacle moment and arguably a turning point that may have saved many lives.  
 

The ongoing battle

 
Important to note like security today you can have a secure password but if you leave post it notes by your computer containing the password then that security is compromised and it was the same scenario then especially with guarding the enigma machine, its keys and codebooks.  It still relies on the humans controlling it and humans make errors and mistakes whether that being lax in the level of encryption used or leaving documents and machines vulnerable to exposure from your enemy.
 
So, for now Bletchley were ahead of the game and messages were being read quickly enabling the re-routing of traffic but this was always going to short lived, it was a war where it was a matter of keeping up especially when the intel recovered involved data that was constantly changing for example the enigma keys only lasted a certain period of time before being changed again.
 
Yet again we would need to turn to capturing intelligence from weather ships, these would be likely to hold longer term key info due to the nature of their work.  Although they did not necessarily have to encrypt communications they had to decrypt or decipher sensitive info such as location etc sent to them so had to carry the info to do so, that info we really needed.  This time it would be the Lauenberg that would prove the provider (in timeline I have created above).
 
Again, the strategy adopted was to rescue the crew aboard other ships so shield them from the info being gathered so they were none the wiser.  After the June keys had expired from the Munchen capture they were lucky enough to get the July keys quite quickly after.
 

Enigma – Additional rotor

 
By February 1942 the Germans had introduced a new rotor to the enigma machine.  This led to an information blackout at Bletchley whilst they struggled to get to grips with deciphering the new enigma.  Reliance was therefore needed in directional finding.  Essentially manned stations (whatever the weather) that would eventually feed right back to Submarine Tracking DF section but the overall the lack of ULTRA info coming from Bletchley during 1942 undoubtedly resulted in more tragedies and lost lives at sea.

October 1942 would finally bring some hope however tinged with tragedy when vital documents were recovered from U-559 but resulted in two lives lost in recovering the much-needed intelligence.  The George cross was posthumously awarded to those that gave their lives and the documents recovered were a short signal book and most importantly the second edition of the Short Weather Cipher.

Eventually with this additional information progress was made on deciphering the four-rotor enigma and this resulted in again being able to reroute the convoys away from danger thus reducing the number of losses in early 1943.

 
US Involvement

 
British and American cryptanalysts had worked together before in WW1 but from 1940 they began to exchange information again.

Both side of the waters would work well together and secretly in their mission to crack the enigma.
 

Suspicions

 
In 1943 between January and February the diversions made to reroute convoys based on intelligence was working well.  Even though Donitz suspected we had intel the thought of the enigma being compromised was dismissed and the blame laid at directional finding being the cause of successful U-Boat evasion.  Thoughts backed up by the German discovery of new radar equipment in a downed allied plane over Rotterdam.
 
Yes, this new radar system (centimetric radar) was much improved and allowed the detection of surfaced subs without themselves being detected but of course we also now know that many combined forces were working tirelessly behind the scenes in the detection and battle of the Atlantic as a whole.
 
Nevertheless, ongoing concerns and suspicious by the Germans about intelligence sources and techniques meant that subs would be given their own enigma keys for additional security.  
 
Although the Germans themselves had some success in reading our encrypted messages it has been suggested that they had struggled to decipher the communications centring around warships and convoys since around June 1943.
 
The battle was certainly cat and mouse.
 
Secret U-Boat Captures

 
There are reportedly several U-boats that were successfully captured and recovered during WW2.

In June 1944 the US successfully captured U-505 and the capture was classified as top secret and kept from the Germans.  All excluding one crew member were captured and concealed in a US POW camp.

After an unsuccessful attempt to tow the U-110 (after successfully capturing the enigma) the British also had some success in recovering U-570 after it was depth charged by a Hudson.  The submarine was towed to Iceland before being recommissioned by the Royal Navy as HMS Graph.
 

Time to reflect

 
It is important to reflect still on the past and history if only to try to attempt and avoid it happening again.  The sceptical side of me knows that war will and does continue as we only know too well looking at recent events.  With regard to intelligence and breaking the enigma we now know that a great deal of gratitude has to be shown to those intellects who worked tirelessly in a secret and unknown world such as Bletchley Park, but we also know that it was a combined effort of many countries (for example the early pre-war enigma work carried out by the Polish).  The US introduction to the war undoubtedly played its part but all across land, sea and air, and there were many acts of heroism and bravery that brought the required information to the fold and hands of ULTRA to all act their part in the victory of the Battle of the Atlantic.