A U-Boat in the Royal Navy (Part 2)

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U570 Beached

Part 2 – Testing, Secrets & Honour

When Hitler learned the news of U-570’s capture he was understandably furious and declared that the U-Boat was now the most dangerous submarine of the war because of the secrets it could reveal. The British were eager to secure the vessel in port for fear of their war prize being lost to the weather or an enemy attack. To protect against the Germans sinking U-570 the RAF flew continuously around the U-Boat and her escort. U-570 was towed successfully to Iceland arriving at Þorlákshöfn on 29th August 1941. It was decided that the U-Boat should be beached (see above image) as it was feared that the damage sustained in the RAF’s attack would make docking dangerous. The plan was to assess and hopefully repair the damage enough to make her seaworthy and then take her back to the UK. In the meantime Jochiam-Rahmlow and his crew were interned and interrogated.

The job of making the submarine seaworthy again was given to Leiutenant Geroge Colvin, himself a submarine commander having commanded HMS Sunfish. In his report he described the conditions he encountered;

The submarine was then lying broadside on to the surf and listing heavily to starboard… The interior of the submarine was unlit and was in a chaotic state; leaks of oil and water from the broken gauge glasses of internal tanks had combined with vast quantities of provisions, flour, dried peas and beans, soft fruit, clothes, bedding, and the remains of scores of loaves of black bread to form a revolting morass that in places was knee-deep. It was subsequently discovered that in this ship the crew’s W.C. had been converted into a food locker and overturned buckets of excrement added to the general noisome conditions.

—Lieutenant GR Colvin, RN, Ex-German Submarine “U 570” – Report of Proceedings (3 October 1941)

Much to the surprise of the British engineers who went aboard the actual extent of the damage the U-Boat had sustained had been vastly overestimated. The British had assumed that since the U-Boat crew decided to surrender that the damage was quite extensive but aside from a few cracked pipes and a leak in the ballast tanks the vessel was in reasonably good shape. Colvin did make one important note in his report and that was that no damage control efforts appeared to have been undertaken. Colvin and his compatriots began to believe that the U-Boat crew had given a rather poor show of themselves; something that flew in the face of the perception of U-Boat crews being cold and calculated even under pressure. The interrogation of the crew revealed the chaotic situation the inexperienced crew found themselves in that resulted in the decision to surrender.


It was established by interrogation of prisoners that, at the moment of the attack, confusion reigned within the U-Boat. The detonation of the depth charges, the smashing of instruments, the formation of gas, thought by the crew to be chlorine gas, and the entry of a certain amount of water apparently convinced Rahmlow that his boat was lost, for he ordered the crew to don life-jackets and mount the conning tower.

Colvin’s team successfully refloated the vessel, cleared much of the mess and restored lighting. It was then pulled off the beach and was towed along the coast to the British naval base at Hvalfjörður where she was docked to the depot ship HMS Hecla for more substantial repairs. While these repairs were underway British Intelligence agencies swooped in on their latest find, analysing everything down to individual screws in the bulkhead in search of weaknesses that could be exploited. Although not in the war yet two U.S. Navy officers arrived to take a look at it but suspected that the most important parts i.e. the coding machines had been removed already.

The two officers reported;

A large cabinet had been removed from the forward corner of the control room by admiralty personnel soon after the capture and sent to England. . . . In view of the vagueness of the information on the site as to the exact nature of this instrument it is considered important that accurate information be obtained from the Naval Attaché London.

There was some truth in this as the Admiralty did indeed remove some components of the decoding device but U-570’s contribution to cracking the fabled Enigma code was quite small as Jochiam-Rahmlow’s crew had quite effectively destroyed a great deal of it before capture.


Repairs took almost a full month to the point where the vessel was declared seaworthy albeit without its ability to dive due to damage to a hydroplane and on the 29th September 1941 U-570 left Iceland under its own power and with a substantial escort. The Royal Navy prize-crew manning the vessel was lead by Colvin as he now had extensive experience of the workings of the vessel. It was reported that during the journey to Britain an RAF Hudson flew over the U-Boat and signalled with its lamp that the crew claimed ownership. Whether this crew had anything to do with capturing the U-Boat is unclear but it was a morale boosting gesture for both sailors and aircrew. The captured U-Boat arrived at the Vickers shipyard at Barrow-in-Furness where she was to be put in drydock for an even more detailed examination and the careful disarming and removal of her torpedoes as these too were of interest to intelligence agencies. Her arrival was a golden opportunity for the British propaganda machine eager to give the bombed-out British public news of any kind of triumph. British Pathe news filmed the arrival of the submarine on October 3rd 1941.

While the news certainly raised spirits among the British public there was a small group on British soil who were infuriated by it. Grizedale Hall in Cumbria is a large country house in the idyllic Lake District but between 1939 and 1946 it was known as the “U-Boat hotel” as it housed a large number of German U-Boat officers including the U-Boat ace Otto Kretschmer. These were committed Nazis many of whom had narrowly escaped death as their U-Boats sank beneath them.


It was against this backdrop that three of U-570’s officers found themselves when they reached Britain to begin their time as Prisoners of War. Interestingly, Jochiam-Rahmlow was sent to a different camp which left his second officer, Bernhard Berndt, the most senior member of the group. The reception from the other PoWs was hostile to say the least and when Berndt tried to explain what had happened the other prisoners decided to put the three of them on trial in a Court of Honour. The court, illegal under the rules of a British internment camp and therefore kept a secret from the guards, also put Jochiam-Rahmlow on trial in abstentia. Berndt tried to explain the chaos and panic experienced by the very rookie crew but the defence fell on deaf ears. He and Jochiam-Rahmlow were found guilty of cowardice but what their punishment was to be exactly is uncertain as on the night of the 18th October 1941 Berndt escaped. The more romantic claims made about the escape attempt have it that Berndt intended to return to U-570 and destroy her through sabotage in order to redeem himself. It is more likely however that he feared for his life following the guilty verdict reached by the court.

Either way his escape was short lived as he was caught by members of the Home Guard who intended to take him back to Grizedale Hall. When he learned of this Berndt attempted to escape again. This time he was less than successful and was shot by his captors running away. He died instantly and in doing so became the only casualty of the entire U-570 affair.

Part 3 – The Royal Navy’s U-Boat (Coming Soon)


7 responses to “A U-Boat in the Royal Navy (Part 2)

  1. A fascinating account. I’ve heard of similar courts happening in these camps and the outcome a forgone conclusion. Never good. Do we know what the eventual outcome was for the U-boat once examined? Was it scrapped or returned to sea. Be interesting to see.

    Liked by 1 person

  2. Pingback: A U-Boat in the Royal Navy (Part 3) | Defence of the Realm

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  4. Pingback: A U-Boat in the Royal Navy (Part 1) | Defence of the Realm

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